STM32F215xx

STM32F217xx
ARM®-based 32-bit MCU, 150DMIPs, up to 1 MB Flash/128+4KB RAM, crypto,
USB OTG HS/FS, Ethernet, 17 TIMs, 3 ADCs, 15 comm. interfaces & camera
Datasheet - production data

Features . &"'!

® ®
• Core: ARM 32-bit Cortex -M3 CPU (120 MHz
max) with Adaptive real-time accelerator (ART
Accelerator™) allowing 0-wait state execution
performance from Flash memory, MPU, LQFP64 (10 × 10 mm)
150 DMIPS/1.25 DMIPS/MHz (Dhrystone 2.1) LQFP100 (14 × 14 mm)
UFBGA176 (10 × 10 mm)
• Memories LQFP144 (20 × 20 mm)
– Up to 1 Mbyte of Flash memory LQFP176 (24 × 24 mm)
– 512 bytes of OTP memory
•

– Up to 128 + 4 Kbytes of SRAM

• Up to 140 I/O ports with interrupt capability:
– Flexible static memory controller that
– Up to 136 fast I/Os up to 60 MHz
supports Compact Flash, SRAM, PSRAM,
– Up to 138 5 V-tolerant I/Os
NOR and NAND memories
– LCD parallel interface, 8080/6800 modes • Up to 15 communication interfaces
– Up to three I2C interfaces (SMBus/PMBus)
• Clock, reset and supply management
– Up to four USARTs and two UARTs
– From 1.8 to 3.6 V application supply + I/Os
(7.5 Mbit/s, ISO 7816 interface, LIN, IrDA,
– POR, PDR, PVD and BOR modem control)
– 4 to 26 MHz crystal oscillator
– Up to three SPIs (30 Mbit/s), two with
– Internal 16 MHz factory-trimmed RC muxed I2S to achieve audio class accuracy
– 32 kHz oscillator for RTC with calibration via audio PLL or external PLL
– Internal 32 kHz RC with calibration – 2 × CAN interfaces (2.0B Active)
• Low-power modes – SDIO interface
– Sleep, Stop and Standby modes • Advanced connectivity
– VBAT supply for RTC, 20 × 32 bit backup – USB 2.0 full-speed device/host/OTG
registers, and optional 4 Kbytes backup controller with on-chip PHY
SRAM – USB 2.0 high-speed/full-speed
• 3 × 12-bit, 0.5 µs ADCs with up to 24 channels device/host/OTG controller with dedicated
and up to 6 MSPS in triple interleaved mode DMA, on-chip full-speed PHY and ULPI
• 2 × 12-bit D/A converters – 10/100 Ethernet MAC with dedicated DMA:
supports IEEE 1588v2 hardware, MII/RMII
• General-purpose DMA: 16-stream controller
with centralized FIFOs and burst support • 8- to 14-bit parallel camera interface
(48 Mbyte/s max.)
• Up to 17 timers
• Cryptographic acceleration
– Up to twelve 16-bit and two 32-bit timers,
up to 120 MHz, each with up to four – Hardware acceleration for AES 128, 192,
IC/OC/PWM or pulse counter and 256, Triple DES, HASH (MD5, SHA-1)
quadrature (incremental) encoder input – Analog true random number generator
• Debug mode: Serial wire debug (SWD), JTAG, • CRC calculation unit
and Cortex®-M3 Embedded Trace Macrocell™ • 96-bit unique ID

August 2016 DocID17050 Rev 13 1/180

This is information on a product in full production. www.st.com
 STM32F21xxx

Table 1. Device summary

Reference Part numbers

STM32F215RG, STM32F215VG, STM32F215ZG

STM32F215xx
STM32F215RE, STM32F215VE, STM32F215ZE
STM32F217VG, STM32F217IG, STM32F217ZG
STM32F217xx
STM32F217VE, STM32F217IE, STM32F217ZE

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Contents

1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

2 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.1 Full compatibility throughout the family . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3 Functional overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.1 ARM® Cortex®-M3 core with embedded Flash and SRAM . . . . . . . . . . . 20
3.2 Adaptive real-time memory accelerator (ART Accelerator™) . . . . . . . . . 20
3.3 Memory protection unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.4 Embedded Flash memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.5 CRC (cyclic redundancy check) calculation unit . . . . . . . . . . . . . . . . . . . 21
3.6 Embedded SRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.7 Multi-AHB bus matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.8 DMA controller (DMA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.9 Flexible static memory controller (FSMC) . . . . . . . . . . . . . . . . . . . . . . . . 23
3.10 Nested vectored interrupt controller (NVIC) . . . . . . . . . . . . . . . . . . . . . . . 23
3.11 External interrupt/event controller (EXTI) . . . . . . . . . . . . . . . . . . . . . . . . . 24
3.12 Clocks and startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
3.13 Boot modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
3.14 Power supply schemes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.15 Power supply supervisor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.16 Voltage regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.16.1 Regulator ON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.16.2 Regulator OFF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.16.3 Regulator ON/OFF and internal reset ON/OFF availability . . . . . . . . . . 28
3.17 Real-time clock (RTC), backup SRAM and backup registers . . . . . . . . . . 29
3.18 Low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.19 VBAT operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
3.20 Timers and watchdogs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
3.20.1 Advanced-control timers (TIM1, TIM8) . . . . . . . . . . . . . . . . . . . . . . . . . 31
3.20.2 General-purpose timers (TIMx) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
3.20.3 Basic timers TIM6 and TIM7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

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3.20.4 Independent watchdog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

3.20.5 Window watchdog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
3.20.6 SysTick timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
3.21 Inter-integrated circuit interface (I²C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
3.22 Universal synchronous/asynchronous receiver transmitters
(UARTs/USARTs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
3.23 Serial peripheral interface (SPI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
3.24 Inter-integrated sound (I2S) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
3.25 SDIO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
3.26 Ethernet MAC interface with dedicated DMA and IEEE 1588 support . . . 35
3.27 Controller area network (CAN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
3.28 Universal serial bus on-the-go full-speed (OTG_FS) . . . . . . . . . . . . . . . . 36
3.29 Universal serial bus on-the-go high-speed (OTG_HS) . . . . . . . . . . . . . . . 36
3.30 Audio PLL (PLLI2S) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
3.31 Digital camera interface (DCMI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
3.31.1 Cryptographic acceleration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
3.32 True random number generator (RNG) . . . . . . . . . . . . . . . . . . . . . . . . . . 38
3.33 GPIOs (general-purpose inputs/outputs) . . . . . . . . . . . . . . . . . . . . . . . . . 38
3.34 ADCs (analog-to-digital converters) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
3.35 DAC (digital-to-analog converter) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
3.36 Temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
3.37 Serial wire JTAG debug port (SWJ-DP) . . . . . . . . . . . . . . . . . . . . . . . . . . 39
3.38 Embedded Trace Macrocell™ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

4 Pinouts and pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

5 Memory mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

6 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
6.1 Parameter conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
6.1.1 Minimum and maximum values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
6.1.2 Typical values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
6.1.3 Typical curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
6.1.4 Loading capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
6.1.5 Pin input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

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6.1.6 Power supply scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

6.1.7 Current consumption measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
6.2 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
6.3 Operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
6.3.1 General operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
6.3.2 VCAP1/VCAP2 external capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
6.3.3 Operating conditions at power-up / power-down (regulator ON) . . . . . . 75
6.3.4 Operating conditions at power-up / power-down (regulator OFF) . . . . . 75
6.3.5 Embedded reset and power control block characteristics . . . . . . . . . . . 76
6.3.6 Supply current characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
6.3.7 Wakeup time from low-power mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
6.3.8 External clock source characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
6.3.9 Internal clock source characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
6.3.10 PLL characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
6.3.11 PLL spread spectrum clock generation (SSCG) characteristics . . . . . . 97
6.3.12 Memory characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
6.3.13 EMC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
6.3.14 Absolute maximum ratings (electrical sensitivity) . . . . . . . . . . . . . . . . 102
6.3.15 I/O current injection characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
6.3.16 I/O port characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
6.3.17 NRST pin characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
6.3.18 TIM timer characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
6.3.19 Communications interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
6.3.20 12-bit ADC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
6.3.21 DAC electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
6.3.22 Temperature sensor characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
6.3.23 VBAT monitoring characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
6.3.24 Embedded reference voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
6.3.25 FSMC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
6.3.26 Camera interface (DCMI) timing specifications . . . . . . . . . . . . . . . . . . 149
6.3.27 SD/SDIO MMC card host interface (SDIO) characteristics . . . . . . . . . 149
6.3.28 RTC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150

7 Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

7.1 LQFP64 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
7.2 LQFP100 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
7.3 LQFP144 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156

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7.4 LQFP176 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

7.5 UFBGA176+25 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
7.6 Thermal characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166

8 Ordering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167

9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168

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List of tables

Table 1. Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Table 2. STM32F215xx and STM32F217xx: features and peripheral counts. . . . . . . . . . . . . . . . . . 15
Table 3. Regulator ON/OFF and internal reset ON/OFF availability. . . . . . . . . . . . . . . . . . . . . . . . . 28
Table 4. Timer feature comparison . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Table 5. USART feature comparison . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Table 6. Legend/abbreviations used in the pinout table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Table 7. STM32F21x pin and ball definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Table 8. FSMC pin definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Table 9. Alternate function mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Table 10. Voltage characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Table 11. Current characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Table 12. Thermal characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Table 13. General operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Table 14. Limitations depending on the operating power supply range . . . . . . . . . . . . . . . . . . . . . . . 73
Table 15. VCAP1/VCAP2 operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Table 16. Operating conditions at power-up / power-down (regulator ON) . . . . . . . . . . . . . . . . . . . . 75
Table 17. Operating conditions at power-up / power-down (regulator OFF). . . . . . . . . . . . . . . . . . . . 75
Table 18. Embedded reset and power control block characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . 76
Table 19. Typical and maximum current consumption in Run mode, code with data processing
running from Flash memory (ART accelerator enabled) or RAM . . . . . . . . . . . . . . . . . . . 78
Table 20. Typical and maximum current consumption in Run mode, code with data processing
running from Flash memory (ART accelerator disabled) . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Table 21. Typical and maximum current consumption in Sleep mode . . . . . . . . . . . . . . . . . . . . . . . . 82
Table 22. Typical and maximum current consumptions in Stop mode . . . . . . . . . . . . . . . . . . . . . . . . 84
Table 23. Typical and maximum current consumptions in Standby mode . . . . . . . . . . . . . . . . . . . . . 85
Table 24. Typical and maximum current consumptions in VBAT mode. . . . . . . . . . . . . . . . . . . . . . . . 85
Table 25. Peripheral current consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
Table 26. Low-power mode wakeup timings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Table 27. High-speed external user clock characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Table 28. Low-speed external user clock characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Table 29. HSE 4-26 MHz oscillator characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Table 30. LSE oscillator characteristics (fLSE = 32.768 kHz) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Table 31. HSI oscillator characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Table 32. LSI oscillator characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Table 33. Main PLL characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Table 34. PLLI2S (audio PLL) characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Table 35. SSCG parameters constraint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
Table 36. Flash memory characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
Table 37. Flash memory programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
Table 38. Flash memory programming with VPP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Table 39. Flash memory endurance and data retention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Table 40. EMS characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Table 41. EMI characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Table 42. ESD absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Table 43. Electrical sensitivities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Table 44. I/O current injection susceptibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Table 45. I/O static characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
Table 46. Output voltage characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

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Table 47. I/O AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

Table 48. NRST pin characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
Table 49. Characteristics of TIMx connected to the APB1 domain . . . . . . . . . . . . . . . . . . . . . . . . . 110
Table 50. Characteristics of TIMx connected to the APB2 domain . . . . . . . . . . . . . . . . . . . . . . . . . 111
Table 51. I2C characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
Table 52. SCL frequency (fPCLK1= 30 MHz.,VDD = 3.3 V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
Table 53. SPI characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
Table 54. I2S characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Table 55. USB OTG FS startup time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Table 56. USB OTG FS DC electrical characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Table 57. USB OTG FS electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Table 58. USB HS DC electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Table 59. Clock timing parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Table 60. ULPI timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
Table 61. Ethernet DC electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
Table 62. Dynamics characteristics: Ethernet MAC signals for SMI. . . . . . . . . . . . . . . . . . . . . . . . . 122
Table 63. Dynamics characteristics: Ethernet MAC signals for RMII . . . . . . . . . . . . . . . . . . . . . . . . 122
Table 64. Dynamics characteristics: Ethernet MAC signals for MII . . . . . . . . . . . . . . . . . . . . . . . . . 123
Table 65. ADC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
Table 66. ADC accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
Table 67. DAC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
Table 68. Temperature sensor characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Table 69. VBAT monitoring characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Table 70. Embedded internal reference voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Table 71. Asynchronous non-multiplexed SRAM/PSRAM/NOR read timings . . . . . . . . . . . . . . . . . 132
Table 72. Asynchronous non-multiplexed SRAM/PSRAM/NOR write timings . . . . . . . . . . . . . . . . . 133
Table 73. Asynchronous multiplexed PSRAM/NOR read timings. . . . . . . . . . . . . . . . . . . . . . . . . . . 134
Table 74. Asynchronous multiplexed PSRAM/NOR write timings . . . . . . . . . . . . . . . . . . . . . . . . . . 135
Table 75. Synchronous multiplexed NOR/PSRAM read timings . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
Table 76. Synchronous multiplexed PSRAM write timings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
Table 77. Synchronous non-multiplexed NOR/PSRAM read timings . . . . . . . . . . . . . . . . . . . . . . . . 139
Table 78. Synchronous non-multiplexed PSRAM write timings . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Table 79. Switching characteristics for PC Card/CF read and write cycles in
attribute/common space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
Table 80. Switching characteristics for PC Card/CF read and write cycles in I/O space . . . . . . . . . 146
Table 81. Switching characteristics for NAND Flash read cycles . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
Table 82. Switching characteristics for NAND Flash write cycles. . . . . . . . . . . . . . . . . . . . . . . . . . . 149
Table 83. DCMI characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
Table 84. SD/MMC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
Table 85. RTC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
Table 86. LQFP64 - 64-pin, 10 x 10 mm low-profile quad flat
package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
Table 87. LQPF100 - 100-pin, 14 x 14 mm low-profile quad flat package
mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
Table 88. LQFP144 - 144-pin, 20 x 20 mm low-profile quad flat package
mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
Table 89. LQFP176 - 176-pin, 24 x 24 mm low profile quad flat package
mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
Table 90. UFBGA176+25, - 201-ball, 10 x 10 mm, 0.65 mm pitch,
ultra fine pitch ball grid array package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . 163
Table 91. UFBGA176+25 recommended PCB design rules (0.65 mm pitch BGA) . . . . . . . . . . . . . 164
Table 92. Package thermal characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166

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Table 93. Ordering information scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167

Table 94. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168

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List of figures

Figure 1. Compatible board design between STM32F10x and STM32F2xx

for LQFP64 package. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Figure 2. Compatible board design between STM32F10x and STM32F2xx
for LQFP100 package. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 3. Compatible board design between STM32F10x and STM32F2xx
for LQFP144 package. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 4. STM32F21x block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Figure 5. Multi-AHB matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Figure 6. Regulator OFF/internal reset ON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Figure 7. Startup in regulator OFF: slow VDD slope,
power-down reset risen after VCAP_1/VCAP_2 stabilization . . . . . . . . . . . . . . . . . . . . . . . . . 28
Figure 8. Startup in regulator OFF: fast VDD slope,
power-down reset risen before VCAP_1/VCAP_2 stabilization. . . . . . . . . . . . . . . . . . . . . . . . 28
Figure 9. STM32F21x LQFP64 pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Figure 10. STM32F21x LQFP100 pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Figure 11. STM32F21x LQFP144 pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Figure 12. STM32F21x LQFP176 pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Figure 13. STM32F21x UFBGA176 ballout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Figure 14. Memory map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Figure 15. Pin loading conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Figure 16. Pin input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Figure 17. Power supply scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Figure 18. Current consumption measurement scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Figure 19. Number of wait states versus fCPU and VDD range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Figure 20. External capacitor CEXT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Figure 21. Typical current consumption vs. temperature, Run mode, code with data
processing running from RAM, and peripherals ON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Figure 22. Typical current consumption vs. temperature, Run mode, code with data
processing running from RAM, and peripherals OFF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Figure 23. Typical current consumption vs. temperature, Run mode, code with data
processing running from Flash, ART accelerator OFF, peripherals ON . . . . . . . . . . . . . . . 81
Figure 24. Typical current consumption vs. temperature, Run mode, code with data
processing running from Flash, ART accelerator OFF, peripherals OFF . . . . . . . . . . . . . . 81
Figure 25. Typical current consumption vs. temperature in Sleep mode,
peripherals ON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Figure 26. Typical current consumption vs. temperature in Sleep mode,
peripherals OFF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Figure 27. Typical current consumption vs. temperature in Stop mode. . . . . . . . . . . . . . . . . . . . . . . . 84
Figure 28. High-speed external clock source AC timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
Figure 29. Low-speed external clock source AC timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
Figure 30. Typical application with an 8 MHz crystal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Figure 31. Typical application with a 32.768 kHz crystal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Figure 32. ACCHSI versus temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Figure 33. ACCLSI versus temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Figure 34. PLL output clock waveforms in center spread mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Figure 35. PLL output clock waveforms in down spread mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Figure 36. FT I/O input characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Figure 37. I/O AC characteristics definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

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Figure 38. Recommended NRST pin protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

Figure 39. I2C bus AC waveforms and measurement circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
Figure 40. SPI timing diagram - slave mode and CPHA = 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
Figure 41. SPI timing diagram - slave mode and CPHA = 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
Figure 42. SPI timing diagram - master mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Figure 43. I2S slave timing diagram (Philips protocol)(1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
Figure 44. I2S master timing diagram (Philips protocol)(1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
Figure 45. USB OTG FS timings: definition of data signal rise and fall time . . . . . . . . . . . . . . . . . . . 120
Figure 46. ULPI timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
Figure 47. Ethernet SMI timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
Figure 48. Ethernet RMII timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
Figure 49. Ethernet MII timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
Figure 50. ADC accuracy characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
Figure 51. Typical connection diagram using the ADC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
Figure 52. Power supply and reference decoupling (VREF+ not connected to VDDA). . . . . . . . . . . . . 127
Figure 53. Power supply and reference decoupling (VREF+ connected to VDDA). . . . . . . . . . . . . . . . 128
Figure 54. 12-bit buffered/non-buffered DAC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Figure 55. Asynchronous non-multiplexed SRAM/PSRAM/NOR read waveforms . . . . . . . . . . . . . . 132
Figure 56. Asynchronous non-multiplexed SRAM/PSRAM/NOR write waveforms . . . . . . . . . . . . . . 133
Figure 57. Asynchronous multiplexed PSRAM/NOR read waveforms. . . . . . . . . . . . . . . . . . . . . . . . 134
Figure 58. Asynchronous multiplexed PSRAM/NOR write waveforms . . . . . . . . . . . . . . . . . . . . . . . 135
Figure 59. Synchronous multiplexed NOR/PSRAM read timings . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
Figure 60. Synchronous multiplexed PSRAM write timings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
Figure 61. Synchronous non-multiplexed NOR/PSRAM read timings . . . . . . . . . . . . . . . . . . . . . . . . 139
Figure 62. Synchronous non-multiplexed PSRAM write timings . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Figure 63. PC Card/CompactFlash controller waveforms for common memory read access . . . . . . 142
Figure 64. PC Card/CompactFlash controller waveforms for common memory write access . . . . . . 142
Figure 65. PC Card/CompactFlash controller waveforms for attribute memory read access . . . . . . 143
Figure 66. PC Card/CompactFlash controller waveforms for attribute memory write access . . . . . . 144
Figure 67. PC Card/CompactFlash controller waveforms for I/O space read access . . . . . . . . . . . . 144
Figure 68. PC Card/CompactFlash controller waveforms for I/O space write access . . . . . . . . . . . . 145
Figure 69. NAND controller waveforms for read access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
Figure 70. NAND controller waveforms for write access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
Figure 71. NAND controller waveforms for common memory read access . . . . . . . . . . . . . . . . . . . . 148
Figure 72. NAND controller waveforms for common memory write access. . . . . . . . . . . . . . . . . . . . 148
Figure 73. SDIO high-speed mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
Figure 74. SD default mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
Figure 75. LQFP64 - 64-pin, 10 x 10 mm low-profile quad flat package outline . . . . . . . . . . . . . . . . 151
Figure 76. LQFP64 - 64-pin, 10 x 10 mm low-profile quad flat package
recommended footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
Figure 77. LQFP100 - 100-pin, 14 x 14 mm low-profile quad flat package outline . . . . . . . . . . . . . . 153
Figure 78. LQFP100 - 100-pin, 14 x 14 mm low-profile quad flat
recommended footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
Figure 79. LQFP100 marking (package top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
Figure 80. LQFP144 - 144-pin, 20 x 20 mm low-profile quad flat package outline . . . . . . . . . . . . . . 156
Figure 81. LQFP144 - 144-pin,20 x 20 mm low-profile quad flat package
recommended footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
Figure 82. LQFP144 marking (package top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
Figure 83. LQFP176 - 176-pin, 24 x 24 mm low profile quad flat package outline . . . . . . . . . . . . . . 160
Figure 84. LQFP176 - 176-pin, 24 x 24 mm low profile quad flat package
recommended footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
Figure 85. UFBGA176+25 - 201-ball, 10 x 10 mm, 0.65 mm pitch,

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List of figures STM32F21xxx

ultra fine pitch ball grid array package outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

Figure 86. UFBGA176+25 - 201-ball, 10 x 10 mm, 0.65 mm pitch, ultra fine pitch ball
grid array package recommended footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164
Figure 87. UFBGA176+25 marking (package top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

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STM32F21xxx Introduction

1 Introduction

This datasheet provides the description of the STM32F215xx and STM32F217xx lines of
microcontrollers. For more details on the whole STMicroelectronics STM32 family, refer to
Section 2.1: Full compatibility throughout the family.
The STM32F215xx and STM32F217xx datasheet should be read in conjunction with the
STM32F20x/STM32F21x reference manual. They will be referred to as STM32F21x devices
throughout the document.
For information on programming, erasing and protection of the internal Flash memory, refer
to the STM32F20x/STM32F21x Flash programming manual (PM0059).
The reference and Flash programming manuals are both available from the
STMicroelectronics website www.st.com.
For information on the Cortex®-M3 core refer to the Cortex®-M3 Technical Reference
Manual, available from the www.arm.com website.

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179
Description STM32F21xxx

2 Description

The STM32F21x family is based on the high-performance ARM® Cortex®-M3 32-bit RISC
core operating at a frequency of up to 120 MHz. The family incorporates high-speed
embedded memories (Flash memory up to 1 Mbyte, up to 128 Kbytes of system SRAM), up
to 4 Kbytes of backup SRAM, and an extensive range of enhanced I/Os and peripherals
connected to two APB buses, three AHB buses and a 32-bit multi-AHB bus matrix.
The devices also feature an adaptive real-time memory accelerator (ART Accelerator™)
that allows to achieve a performance equivalent to 0 wait state program execution from
Flash memory at a CPU frequency up to 120 MHz. This performance has been validated
using the CoreMark® benchmark.
All devices offer three 12-bit ADCs, two DACs, a low-power RTC, twelve general-purpose
16-bit timers including two PWM timers for motor control, two general-purpose 32-bit timers.
a true number random generator (RNG). They also feature standard and advanced
communication interfaces. New advanced peripherals include an SDIO, an enhanced
flexible static memory control (FSMC) interface (for devices offered in packages of 100 pins
and more), a cryptographic acceleration cell, and a camera interface for CMOS sensors.
The devices also feature standard peripherals.
• Up to three I2Cs
• Three SPIs, two I2Ss. To achieve audio class accuracy, the I2S peripherals can be
clocked via a dedicated internal audio PLL or via an external PLL to allow
synchronization.
• Four USARTs and two UARTs
• A USB OTG high-speed with full-speed capability (with the ULPI)
• A second USB OTG (full-speed)
• Two CANs
• An SDIO interface
• Ethernet and camera interface available on STM32F217xx devices only.
Note: The STM32F215xx and STM32F217xx devices operate in the –40 to +105 °C temperature
range from a 1.8 V to 3.6 V power supply.
A comprehensive set of power-saving modes allow the design of low-power applications.
STM32F215xx and STM32F217xx devices are offered in various packages ranging from 64
pins to 176 pins. The set of included peripherals changes with the device chosen.These
features make the STM32F215xx and STM32F217xx microcontroller family suitable for a
wide range of applications:
• Motor drive and application control
• Medical equipment
• Industrial applications: PLC, inverters, circuit breakers
• Printers, and scanners
• Alarm systems, video intercom, and HVAC
• Home audio appliances
Figure 4 shows the general block diagram of the device family.

14/180 DocID17050 Rev 13

 Table 2. STM32F215xx and STM32F217xx: features and peripheral counts

STM32F21xxx
Peripherals STM32F215Rx STM32F215Vx STM32F215Zx STM32F217Vx STM32F217Zx STM32F217Ix

Flash memory in Kbytes 512 1024 512 1024 512 1024 512 1024 512 1024 512 1024

System 128(112+16)
SRAM in Kbytes
Backup 4 4 4 4 4 4

FSMC memory controller No Yes(1)

Ethernet(2) No Yes

General-purpose 10

Advanced-control 2

Timers Basic 2

IWDG Yes

WWDG Yes

RTC Yes

Random number generator Yes

DocID17050 Rev 13

SPI / (I2S) 3/(2)(3)

I2C 3

USART 4
Communication UART 2
interfaces
USB OTG FS Yes

USB OTG HS Yes

CAN 2
(2)
Camera interface No Yes

Encryption Yes

GPIOs 51 82 114 82 114 140

SDIO Yes

12-bit ADC 3
Number of channels 16 16 24 16 24 24

12-bit DAC Yes

Number of channels 2

Maximum CPU frequency 120 MHz

Description
Operating voltage 1.8 V to 3.6 V
15/10
 Table 2. STM32F215xx and STM32F217xx: features and peripheral counts (continued)
16/10

Description
Peripherals STM32F215Rx STM32F215Vx STM32F215Zx STM32F217Vx STM32F217Zx STM32F217Ix

Ambient temperatures: –40 to +85 °C /–40 to +105 °C

Operating temperatures
Junction temperature: –40 to + 125 °C

Package LQFP64 LQFP100 LQFP144 LQFP100 LQFP144 UFBGA176, LQFP176

1. For the LQFP100 package, only FSMC Bank1 or Bank2 are available. Bank1 can only support a multiplexed NOR/PSRAM memory using the NE1 Chip Select. Bank2 can
only support a 16- or 8-bit NAND Flash memory using the NCE2 Chip Select. The interrupt line cannot be used since Port G is not available in this package.
2. Camera interface and Ethernet are available only in STM32F217x devices.
3. The SPI2 and SPI3 interfaces give the flexibility to work in an exclusive way in either the SPI mode or the I2S audio mode.
DocID17050 Rev 13

STM32F21xxx
STM32F21xxx Description

2.1 Full compatibility throughout the family

The STM32F215xx and STM32F217xx constitute the STM32F21x family whose members
are fully pin-to-pin, software and feature compatible, allowing the user to try different
memory densities and peripherals for a greater degree of freedom during the development
cycle.
The STM32F215xx and STM32F217xx devices maintain a close compatibility with the
whole STM32F10xxx family. All functional pins are pin-to-pin compatible. The
STM32F215xx and STM32F217xx, however, are not drop-in replacements for the
STM32F10xxx devices: the two families do not have the same power scheme, and so their
power pins are different. Nonetheless, transition from the STM32F10xxx to the STM32F21x
family remains simple as only a few pins are impacted.
Figure 1, Figure 2 and Figure 3 provide compatible board designs between the STM32F21x
and the STM32F10xxx family.

Figure 1. Compatible board design between STM32F10x and STM32F2xx

for LQFP64 package

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DocID17050 Rev 13 17/180

179
Description STM32F21xxx

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18/180 DocID17050 Rev 13

STM32F21xxx Description

Figure 4. STM32F21x block diagram

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1. The timers connected to APB2 are clocked from TIMxCLK up to 120 MHz, while the timers connected to APB1 are clocked
from TIMxCLK up to 60 MHz.
2. The camera interface and Ethernet are available only in STM32F217xx devices.

DocID17050 Rev 13 19/180

179
Functional overview STM32F21xxx

3 Functional overview

3.1 ARM® Cortex®-M3 core with embedded Flash and SRAM

The ARM® Cortex®-M3 processor is the latest generation of ARM processors for embedded
systems. It was developed to provide a low-cost platform that meets the needs of MCU
implementation, with a reduced pin count and low-power consumption, while delivering
outstanding computational performance and an advanced response to interrupts.
The ARM® Cortex®-M3 32-bit RISC processor features exceptional code-efficiency,
delivering the high-performance expected from an ARM core in the memory size usually
associated with 8- and 16-bit devices.
With its embedded ARM® core, the STM32F21x family is compatible with all ARM® tools
and software.
Figure 4 shows the general block diagram of the STM32F21x family.

3.2 Adaptive real-time memory accelerator (ART Accelerator™)

The ART Accelerator™ is a memory accelerator which is optimized for STM32 industry-
standard ARM® Cortex®-M3 processors. It balances the inherent performance advantage of
the ARM® Cortex®-M3 over Flash memory technologies, which normally requires the
processor to wait for the Flash memory at higher operating frequencies.
To release the processor full 150 DMIPS performance at this frequency, the accelerator
implements an instruction prefetch queue and branch cache which increases program
execution speed from the 128-bit Flash memory. Based on CoreMark® benchmark, the
performance achieved thanks to the ART accelerator is equivalent to 0 wait state program
execution from Flash memory at a CPU frequency up to 120 MHz.

3.3 Memory protection unit

The memory protection unit (MPU) is used to manage the CPU accesses to memory to
prevent one task to accidentally corrupt the memory or resources used by any other active
task. This memory area is organized into up to 8 protected areas that can in turn be divided
up into 8 subareas. The protection area sizes are between 32 bytes and the whole 4
gigabytes of addressable memory.
The MPU is especially helpful for applications where some critical or certified code has to be
protected against the misbehavior of other tasks. It is usually managed by an RTOS (real-
time operating system). If a program accesses a memory location that is prohibited by the
MPU, the RTOS can detect it and take action. In an RTOS environment, the kernel can
dynamically update the MPU area setting, based on the process to be executed.
The MPU is optional and can be bypassed for applications that do not need it.

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STM32F21xxx Functional overview

3.4 Embedded Flash memory

The STM32F21x devices embed a 128-bit wide Flash memory of 128 Kbytes, 256 Kbytes,
512 Kbytes, 768 Kbytes or 1 Mbyte available for storing programs and data.
The devices also feature 512 bytes of OTP memory that can be used to store critical user
data such as Ethernet MAC addresses or cryptographic keys.

3.5 CRC (cyclic redundancy check) calculation unit

The CRC (cyclic redundancy check) calculation unit is used to get a CRC code from a 32-bit
data word and a fixed generator polynomial.
Among other applications, CRC-based techniques are used to verify data transmission or
storage integrity. In the scope of the EN/IEC 60335-1 standard, they offer a means of
verifying the Flash memory integrity. The CRC calculation unit helps compute a software
signature during runtime, to be compared with a reference signature generated at link-time
and stored at a given memory location.

3.6 Embedded SRAM

All STM32F21x products embed:
• Up to 128 Kbytes of system SRAM accessed (read/write) at CPU clock speed with 0
wait states
• 4 Kbytes of backup SRAM.
The content of this area is protected against possible unwanted write accesses, and is
retained in Standby or VBAT mode.

3.7 Multi-AHB bus matrix

The 32-bit multi-AHB bus matrix interconnects all the masters (CPU, DMAs, Ethernet, USB
HS) and the slaves (Flash memory, RAM, FSMC, AHB and APB peripherals) and ensures a
seamless and efficient operation even when several high-speed peripherals work
simultaneously.

DocID17050 Rev 13 21/180

179
Functional overview STM32F21xxx

Figure 5. Multi-AHB matrix

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3.8 DMA controller (DMA)

The devices feature two general-purpose dual-port DMAs (DMA1 and DMA2) with 8
streams each. They are able to manage memory-to-memory, peripheral-to-memory and
memory-to-peripheral transfers. They share some centralized FIFOs for APB/AHB
peripherals, support burst transfer and are designed to provide the maximum peripheral
bandwidth (AHB/APB).
The two DMA controllers support circular buffer management, so that no specific code is
needed when the controller reaches the end of the buffer. The two DMA controllers also
have a double buffering feature, which automates the use and switching of two memory
buffers without requiring any special code.
Each stream is connected to dedicated hardware DMA requests, with support for software
trigger on each stream. Configuration is made by software and transfer sizes between
source and destination are independent.

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STM32F21xxx Functional overview

The DMA can be used with the main peripherals:

• SPI and I2S
• I2C
• USART and UART
• General-purpose, basic and advanced-control timers TIMx
• DAC
• SDIO
• Cryptographic acceleration
• Camera interface (DCMI)
• ADC.

3.9 Flexible static memory controller (FSMC)

The FSMC is embedded in all STM32F21x devices. It has four Chip Select outputs
supporting the following modes: PC Card/Compact Flash, SRAM, PSRAM, NOR Flash and
NAND Flash.
Functionality overview:
• Write FIFO
• Code execution from external memory except for NAND Flash and PC Card
• Maximum frequency (fHCLK) for external access is 60 MHz

LCD parallel interface

The FSMC can be configured to interface seamlessly with most graphic LCD controllers. It
supports the Intel 8080 and Motorola 6800 modes, and is flexible enough to adapt to
specific LCD interfaces. This LCD parallel interface capability makes it easy to build cost-
effective graphic applications using LCD modules with embedded controllers or high
performance solutions using external controllers with dedicated acceleration.

3.10 Nested vectored interrupt controller (NVIC)

The STM32F21x devices embed a nested vectored interrupt controller able to manage 16
priority levels, and handle up to 81 maskable interrupt channels plus the 16 interrupt lines of
the Cortex®-M3.
The NVIC main features are the following:
• Closely coupled NVIC gives low-latency interrupt processing
• Interrupt entry vector table address passed directly to the core
• Closely coupled NVIC core interface
• Allows early processing of interrupts
• Processing of late arriving, higher-priority interrupts
• Support tail chaining
• Processor state automatically saved
• Interrupt entry restored on interrupt exit with no instruction overhead

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Functional overview STM32F21xxx

This hardware block provides flexible interrupt management features with minimum interrupt
latency.

3.11 External interrupt/event controller (EXTI)

The external interrupt/event controller consists of 23 edge-detector lines used to generate
interrupt/event requests. Each line can be independently configured to select the trigger
event (rising edge, falling edge, both) and can be masked independently. A pending register
maintains the status of the interrupt requests. The EXTI can detect an external line with a
pulse width shorter than the Internal APB2 clock period. Up to 140 GPIOs can be connected
to the 16 external interrupt lines.

3.12 Clocks and startup

On reset the 16 MHz internal RC oscillator is selected as the default CPU clock. The
16 MHz internal RC oscillator is factory-trimmed to offer 1% accuracy. The application can
then select as system clock either the RC oscillator or an external 4-26 MHz clock source.
This clock is monitored for failure. If failure is detected, the system automatically switches
back to the internal RC oscillator and a software interrupt is generated (if enabled). Similarly,
full interrupt management of the PLL clock entry is available when necessary (for example if
an indirectly used external oscillator fails).
The advanced clock controller clocks the core and all peripherals using a single crystal or
oscillator. In particular, the ethernet and USB OTG FS peripherals can be clocked by the
system clock.
Several prescalers and PLLs allow the configuration of the three AHB buses, the high-
speed APB (APB2) and the low-speed APB (APB1) domains. The maximum frequency of
the three AHB buses is 120 MHz and the maximum frequency the high-speed APB domains
is 60 MHz. The maximum allowed frequency of the low-speed APB domain is 30 MHz.
The devices embed a dedicate PLL (PLLI2S) that allow them to achieve audio class
performance. In this case, the I2S master clock can generate all standard sampling
frequencies from 8 kHz to 192 kHz.

3.13 Boot modes

At startup, boot pins are used to select one out of three boot options:
• Boot from user Flash
• Boot from system memory
• Boot from embedded SRAM
The boot loader is located in system memory. It is used to reprogram the Flash memory by
using USART1 (PA9/PA10), USART3 (PC10/PC11 or PB10/PB11), CAN2 (PB5/PB13), USB
OTG FS in Device mode (PA11/PA12) through DFU (device firmware upgrade).

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STM32F21xxx Functional overview

3.14 Power supply schemes

• VDD = 1.8 to 3.6 V: external power supply for I/Os and the internal regulator (when
enabled), provided externally through VDD pins.
• VSSA, VDDA = 1.8 to 3.6 V: external analog power supplies for ADC, DAC, Reset
blocks, RCs and PLL. VDDA and VSSA must be connected to VDD and VSS, respectively.
• VBAT = 1.65 to 3.6 V: power supply for RTC, external clock, 32 kHz oscillator and
backup registers (through power switch) when VDD is not present.
Refer to Figure 17: Power supply scheme for more details.

3.15 Power supply supervisor

The devices have an integrated power-on reset (POR) / power-down reset (PDR) circuitry
coupled with a Brownout reset (BOR) circuitry.
At power-on, POR/PDR is always active and ensures proper operation starting from 1.8 V.
After the 1.8 V POR threshold level is reached, the option byte loading process starts, either
to confirm or modify default BOR threshold levels, or to disable BOR permanently. Three
BOR thresholds are available through option bytes.
The device remains in reset mode when VDD is below a specified threshold, VPOR/PDR or
VBOR, without the need for an external reset circuit. .
The devices also feature an embedded programmable voltage detector (PVD) that monitors
the VDD/VDDA power supply and compares it to the VPVD threshold. An interrupt can be
generated when VDD/VDDA drops below the VPVD threshold and/or when VDD/VDDA is
higher than the VPVD threshold. The interrupt service routine can then generate a warning
message and/or put the MCU into a safe state. The PVD is enabled by software.

3.16 Voltage regulator

The regulator has four operating modes:
• Regulator ON
– Main regulator mode (MR)
– Low-power regulator (LPR)
– Power-down
• Regulator OFF
– Regulator OFF/internal reset ON

3.16.1 Regulator ON
The regulator ON modes are activated by default on LQFP packages. On UFBGA176
package, they are activated by connecting REGOFF to VSS.
VDD minimum value is 1.8 V.

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Functional overview STM32F21xxx

There are three power modes configured by software when the regulator is ON:
• MR is used in the nominal regulation mode
• LPR is used in Stop modes
The LP regulator mode is configured by software when entering Stop mode.
• Power-down is used in Standby mode.
The Power-down mode is activated only when entering Standby mode. The regulator
output is in high impedance and the kernel circuitry is powered down, inducing zero
consumption. The contents of the registers and SRAM are lost).
Two external ceramic capacitors should be connected on VCAP_1 and VCAP_2 pin. Refer to
Figure 17: Power supply scheme and Table 15: VCAP1/VCAP2 operating conditions.
All packages have the regulator ON feature.

3.16.2 Regulator OFF

This feature is available only on packages featuring the REGOFF pin. The regulator is
disabled by holding REGOFF high. The regulator OFF mode allows to supply externally a
V12 voltage source through VCAP_1 and VCAP_2 pins.
The two 2.2 µF ceramic capacitors should be replaced by two 100 nF decoupling
capacitors. Refer to Figure 17: Power supply scheme.
When the regulator is OFF, there is no more internal monitoring on V12. An external power
supply supervisor should be used to monitor the V12 of the logic power domain. PA0 pin
should be used for this purpose, and act as power-on reset on V12 power domain.
In regulator OFF mode, the following features are no more supported:
• PA0 cannot be used as a GPIO pin since it allows to reset the part of the 1.2 V logic
power domain which is not reset by the NRST pin.
• As long as PA0 is kept low, the debug mode cannot be used at power-on reset. As a
consequence, PA0 and NRST pins must be managed separately if the debug
connection at reset or pre-reset is required.

Regulator OFF/internal reset ON

On UFBGA176 package, REGOFF must be connected to VDD.
The regulator OFF/internal reset ON mode allows to supply externally a 1.2 V voltage
source through VCAP_1 and VCAP_2 pins, in addition to VDD.

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STM32F21xxx Functional overview

Figure 6. Regulator OFF/internal reset ON

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The following conditions must be respected:

• VDD should always be higher than VCAP_1 and VCAP_2 to avoid current injection
between power domains.
• If the time for VCAP_1 and VCAP_2 to reach 1.08 V is faster than the time for VDD to
reach 1.8 V, then PA0 should be kept low to cover both conditions: until VCAP_1 and
VCAP_2 reach 1.08 V and until VDD reaches 1.8 V (see Figure 7).
• Otherwise, If the time for VCAP_1 and VCAP_2 to reach 1.08 V is slower than the time for
VDD to reach 1.8 V, then PA0 should be asserted low externally (see Figure 8).
• If VCAP_1 and VCAP_2 go below 1.08 V and VDD is higher than 1.8 V, then a reset must
be asserted on PA0 pin.
integrated power-on reset (POR)/ power-down reset (PDR) circuitry is disabled.
An external power supply supervisor should monitor both the external 1.2 V and the external
VDD supply voltage, and should maintain the device in reset mode as long as they remain
below a specified threshold. The VDD specified threshold, below which the device must be
maintained under reset, is 1.8 V. This supply voltage can drop to 1.7 V when the device
operates in the 0 to 70 °C temperature range. A comprehensive set of power-saving modes
allows the design of low-power applications.

DocID17050 Rev 13 27/180

179
Functional overview STM32F21xxx

Figure 7. Startup in regulator OFF: slow VDD slope,

power-down reset risen after VCAP_1/VCAP_2 stabilization

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3.16.3 Regulator ON/OFF and internal reset ON/OFF availability

Table 3. Regulator ON/OFF and internal reset ON/OFF availability

Regulator ON/internal Regulator ON/internal Regulator
Package
reset ON reset OFF OFF/internal reset ON

LQFP64
LQFP100
Yes No No
LQFP144
LQFP176
Yes Yes
UFBGA176 No
REGOFF set to VSS REGOFF set to VDD

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STM32F21xxx Functional overview

3.17 Real-time clock (RTC), backup SRAM and backup registers

The backup domain of the STM32F21x devices includes:
• The real-time clock (RTC)
• 4 Kbytes of backup SRAM
• 20 backup registers
The real-time clock (RTC) is an independent BCD timer/counter. Its main features are the
following:
• Dedicated registers contain the second, minute, hour (in 12/24 hour), week day, date,
month, year, in BCD (binary-coded decimal) format.
• Automatic correction for 28, 29 (leap year), 30, and 31 day of the month.
• Programmable alarm and programmable periodic interrupts with wakeup from Stop and
Standby modes.
• It is clocked by a 32.768 kHz external crystal, resonator or oscillator, the internal low-
power RC oscillator or the high-speed external clock divided by 128. The internal low-
speed RC has a typical frequency of 32 kHz. The RTC can be calibrated using an
external 512 Hz output to compensate for any natural quartz deviation.
• Two alarm registers are used to generate an alarm at a specific time and calendar
fields can be independently masked for alarm comparison. To generate a periodic
interrupt, a 16-bit programmable binary auto-reload downcounter with programmable
resolution is available and allows automatic wakeup and periodic alarms from every
120 µs to every 36 hours.
• A 20-bit prescaler is used for the time base clock. It is by default configured to generate
a time base of 1 second from a clock at 32.768 kHz.
• Reference clock detection: a more precise second source clock (50 or 60 Hz) can be
used to enhance the calendar precision.
The 4-Kbyte backup SRAM is an EEPROM-like area.It can be used to store data which
need to be retained in VBAT and standby mode.This memory area is disabled to minimize
power consumption (see Section 3.18: Low-power modes). It can be enabled by software.
The backup registers are 32-bit registers used to store 80 bytes of user application data
when VDD power is not present. Backup registers are not reset by a system, a power reset,
or when the device wakes up from the Standby mode (see Section 3.18: Low-power
modes).
Like backup SRAM, the RTC and backup registers are supplied through a switch that is
powered either from the VDD supply when present or the VBAT pin.

3.18 Low-power modes

The STM32F21x family supports three low-power modes to achieve the best compromise
between low-power consumption, short startup time and available wakeup sources:
• Sleep mode
In Sleep mode, only the CPU is stopped. All peripherals continue to operate and can
wake up the CPU when an interrupt/event occurs.
• Stop mode
The Stop mode achieves the lowest power consumption while retaining the contents of
SRAM and registers. All clocks in the 1.2 V domain are stopped, the PLL, the HSI RC

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and the HSE crystal oscillators are disabled. The voltage regulator can also be put
either in normal or in low-power mode.
The device can be woken up from the Stop mode by any of the EXTI line. The EXTI line
source can be one of the 16 external lines, the PVD output, the RTC alarm / wakeup /
tamper / time stamp events, the USB OTG FS/HS wakeup or the Ethernet wakeup.
• Standby mode
The Standby mode is used to achieve the lowest power consumption. The internal
voltage regulator is switched off so that the entire 1.2 V domain is powered off. The
PLL, the HSI RC and the HSE crystal oscillators are also switched off. After entering
Standby mode, the SRAM and register contents are lost except for registers in the
backup domain and the backup SRAM when selected.
The device exits the Standby mode when an external reset (NRST pin), an IWDG reset,
a rising edge on the WKUP pin, or an RTC alarm / wakeup / tamper /time stamp event
occurs.
Note: The RTC, the IWDG, and the corresponding clock sources are not stopped when the device
enters the Stop or Standby mode.

3.19 VBAT operation

The VBAT pin allows to power the device VBAT domain from an external battery or an
external supercapacitor.
VBAT operation is activated when VDD is not present.
The VBAT pin supplies the RTC, the backup registers and the backup SRAM.
Note: When the microcontroller is supplied from VBAT, external interrupts and RTC alarm/events
do not exit it from VBAT operation.

3.20 Timers and watchdogs

The STM32F21x devices include two advanced-control timers, eight general-purpose
timers, two basic timers and two watchdog timers.
All timer counters can be frozen in debug mode.
Table 4 compares the features of the advanced-control, general-purpose and basic timers.

Table 4. Timer feature comparison

DMA Capture/ Max Max
Counter Counter Prescaler Complementary
Timer type Timer request compare interface timer
resolution type factor output
generation channels clock clock

Up, Any integer

Advanced- TIM1, 60 120
16-bit Down, between 1 Yes 4 Yes
control TIM8 MHz MHz
Up/down and 65536

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Table 4. Timer feature comparison (continued)

DMA Capture/ Max Max
Counter Counter Prescaler Complementary
Timer type Timer request compare interface timer
resolution type factor output
generation channels clock clock

Up, Any integer

TIM2, 30 60
32-bit Down, between 1 Yes 4 No
TIM5 MHz MHz
General Up/down and 65536
purpose Up, Any integer
TIM3, 30 60
16-bit Down, between 1 Yes 4 No
TIM4 MHz MHz
Up/down and 65536
Any integer
TIM6, 30 60
Basic 16-bit Up between 1 Yes 0 No
TIM7 MHz MHz
and 65536
Any integer
60 120
TIM9 16-bit Up between 1 No 2 No
MHz MHz
and 65536
Any integer
TIM10, 60 120
16-bit Up between 1 No 1 No
TIM11 MHz MHz
General and 65536
purpose Any integer
30 60
TIM12 16-bit Up between 1 No 2 No
MHz MHz
and 65536
Any integer
TIM13, 30 60
16-bit Up between 1 No 1 No
TIM14 MHz MHz
and 65536

3.20.1 Advanced-control timers (TIM1, TIM8)

The advanced-control timers (TIM1, TIM8) can be seen as three-phase PWM generators
multiplexed on 6 channels. They have complementary PWM outputs with programmable
inserted dead times. They can also be considered as complete general-purpose timers.
Their 4 independent channels can be used for:
• Input capture
• Output compare
• PWM generation (edge- or center-aligned modes)
• One-pulse mode output
If configured as standard 16-bit timers, they have the same features as the general-purpose
TIMx timers. If configured as 16-bit PWM generators, they have full modulation capability (0-
100%).
The TIM1 and TIM8 counters can be frozen in debug mode. Many of the advanced-control
timer features are shared with those of the standard TIMx timers which have the same
architecture. The advanced-control timer can therefore work together with the TIMx timers
via the Timer Link feature for synchronization or event chaining.

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3.20.2 General-purpose timers (TIMx)

There are ten synchronizable general-purpose timers embedded in the STM32F21x devices
(see Table 4 for differences).

TIM2, TIM3, TIM4, TIM5

The STM32F21x include 4 full-featured general-purpose timers. TIM2 and TIM5 are 32-bit
timers, and TIM3 and TIM4 are 16-bit timers. The TIM2 and TIM5 timers are based on a 32-
bit auto-reload up/downcounter and a 16-bit prescaler. The TIM3 and TIM4 timers are based
on a 16-bit auto-reload up/downcounter and a 16-bit prescaler. They all feature 4
independent channels for input capture/output compare, PWM or one-pulse mode output.
This gives up to 16 input capture/output compare/PWMs on the largest packages.
The TIM2, TIM3, TIM4, TIM5 general-purpose timers can work together, or with the other
general-purpose timers and the advanced-control timers TIM1 and TIM8 via the Timer Link
feature for synchronization or event chaining.
The counters of TIM2, TIM3, TIM4, TIM5 can be frozen in debug mode. Any of these
general-purpose timers can be used to generate PWM outputs.
TIM2, TIM3, TIM4, TIM5 all have independent DMA request generation. They are capable
of handling quadrature (incremental) encoder signals and the digital outputs from 1 to 4 hall-
effect sensors.

TIM10, TIM11 and TIM9

These timers are based on a 16-bit auto-reload upcounter and a 16-bit prescaler. TIM10 and
TIM11 feature one independent channel, whereas TIM9 has two independent channels for
input capture/output compare, PWM or one-pulse mode output. They can be synchronized
with the TIM2, TIM3, TIM4, TIM5 full-featured general-purpose timers. They can also be
used as simple time bases.

TIM12, TIM13 and TIM14

These timers are based on a 16-bit auto-reload upcounter and a 16-bit prescaler. TIM13 and
TIM14 feature one independent channel, whereas TIM12 has two independent channels for
input capture/output compare, PWM or one-pulse mode output. They can be synchronized
with the TIM2, TIM3, TIM4, TIM5 full-featured general-purpose timers.
They can also be used as simple time bases.

3.20.3 Basic timers TIM6 and TIM7

These timers are mainly used for DAC trigger and waveform generation. They can also be
used as a generic 16-bit time base.

3.20.4 Independent watchdog

The independent watchdog is based on a 12-bit downcounter and 8-bit prescaler. It is
clocked from an independent 32 kHz internal RC and as it operates independently from the
main clock, it can operate in Stop and Standby modes. It can be used either as a watchdog
to reset the device when a problem occurs, or as a free-running timer for application timeout

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management. It is hardware- or software-configurable through the option bytes.

The counter can be frozen in debug mode.

3.20.5 Window watchdog

The window watchdog is based on a 7-bit downcounter that can be set as free-running. It
can be used as a watchdog to reset the device when a problem occurs. It is clocked from
the main clock. It has an early warning interrupt capability and the counter can be frozen in
debug mode.

3.20.6 SysTick timer

This timer is dedicated to real-time operating systems, but could also be used as a standard
downcounter. It features:
• A 24-bit downcounter
• Autoreload capability
• Maskable system interrupt generation when the counter reaches 0
• Programmable clock source

3.21 Inter-integrated circuit interface (I²C)

Up to three I2C bus interfaces can operate in multimaster and slave modes. They can
support the Standard- and Fast-modes. They support the 7/10-bit addressing mode and the
7-bit dual addressing mode (as slave). A hardware CRC generation/verification is
embedded.
They can be served by DMA and they support SMBus 2.0/PMBus.

3.22 Universal synchronous/asynchronous receiver transmitters

(UARTs/USARTs)
The STM32F21x devices embed four universal synchronous/asynchronous receiver
transmitters (USART1, USART2, USART3 and USART6) and two universal asynchronous
receiver transmitters (UART4 and UART5).
These six interfaces provide asynchronous communication, IrDA SIR ENDEC support,
multiprocessor communication mode, single-wire half-duplex communication mode and
have LIN Master/Slave capability. The USART1 and USART6 interfaces are able to
communicate at speeds of up to 7.5 Mbit/s. The other available interfaces communicate at
up to 3.75 Mbit/s.
USART1, USART2, USART3 and USART6 also provide hardware management of the CTS
and RTS signals, Smart Card mode (ISO 7816 compliant) and SPI-like communication
capability. All interfaces can be served by the DMA controller.

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Table 5. USART feature comparison

Max baud rate Max baud rate
USART Standard Modem SPI Smartcard in Mbit/s in Mbit/s APB
LIN irDA
name features (RTS/CTS) master (ISO 7816) (oversampling (oversampling mapping
by 16) by 8)

APB2 (max.
USART1 X X X X X X 1.87 7.5
60 MHz)
APB1 (max.
USART2 X X X X X X 1.87 3.75
30 MHz)
APB1 (max.
USART3 X X X X X X 1.87 3.75
30 MHz)
APB1 (max.
UART4 X - X - X - 1.87 3.75
30 MHz)
APB1 (max.
UART5 X - X - X - 3.75 3.75
30 MHz)
APB2 (max.
USART6 X X X X X X 3.75 7.5
60 MHz)

3.23 Serial peripheral interface (SPI)

The STM32F21x devices feature up to three SPIs in slave and master modes in full-duplex
and simplex communication modes. SPI1 can communicate at up to 30 Mbits/s, while SPI2
and SPI3 can communicate at up to 15 Mbit/s. The 3-bit prescaler gives 8 master mode
frequencies and the frame is configurable to 8 bits or 16 bits. The hardware CRC
generation/verification supports basic SD Card/MMC modes. All SPIs can be served by the
DMA controller.
The SPI interface can be configured to operate in TI mode for communications in master
mode and slave mode.

3.24 Inter-integrated sound (I2S)

Two standard I2S interfaces (multiplexed with SPI2 and SPI3) are available. They can
operate in master or slave mode, in half-duplex communication modes, and can be
configured to operate with a 16-/32-bit resolution as input or output channels. Audio
sampling frequencies from 8 kHz up to 192 kHz are supported. When either or both of the
I2S interfaces is/are configured in master mode, the master clock can be output to the
external DAC/CODEC at 256 times the sampling frequency.
All I2Sx interfaces can be served by the DMA controller.

3.25 SDIO
An SD/SDIO/MMC host interface is available, that supports MultiMediaCard System
Specification Version 4.2 in three different databus modes: 1-bit (default), 4-bit and 8-bit.

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The interface allows data transfer at up to 48 MHz in 8-bit mode, and is compliant with the
SD Memory Card Specification Version 2.0.
The SDIO Card Specification Version 2.0 is also supported with two different databus
modes: 1-bit (default) and 4-bit.
The current version supports only one SD/SDIO/MMC4.2 card at any one time and a stack
of MMC4.1 or previous.
In addition to SD/SDIO/MMC, this interface is fully compliant with the CE-ATA digital
protocol Rev1.1.

3.26 Ethernet MAC interface with dedicated DMA and IEEE 1588
support
Peripheral available only on the STM32F217xx devices.
The STM32F217xx devices provide an IEEE-802.3-2002-compliant media access controller
(MAC) for ethernet LAN communications through an industry-standard medium-
independent interface (MII) or a reduced medium-independent interface (RMII). The
STM32F217xx requires an external physical interface device (PHY) to connect to the
physical LAN bus (twisted-pair, fiber, etc.). the PHY is connected to the STM32F217xx MII
port using 17 signals for MII or 9 signals for RMII, and can be clocked using the 25 MHz
(MII) or 50 MHz (RMII) output from the STM32F217xx.
The STM32F217xx includes the following features:
• Supports 10 and 100 Mbit/s rates
• Dedicated DMA controller allowing high-speed transfers between the dedicated SRAM
and the descriptors (see the STM32F20x and STM32F21x reference manual for
details)
• Tagged MAC frame support (VLAN support)
• Half-duplex (CSMA/CD) and full-duplex operation
• MAC control sublayer (control frames) support
• 32-bit CRC generation and removal
• Several address filtering modes for physical and multicast address (multicast and
group addresses)
• 32-bit status code for each transmitted or received frame
• Internal FIFOs to buffer transmit and receive frames. The transmit FIFO and the
receive FIFO are both 2 Kbytes, that is 4 Kbytes in total
• Supports hardware PTP (precision time protocol) in accordance with IEEE 1588 2008
(PTP V2) with the time stamp comparator connected to the TIM2 input
• Triggers interrupt when system time becomes greater than target time

3.27 Controller area network (CAN)

The two CANs are compliant with the 2.0A and B (active) specifications with a bitrate up to 1
Mbit/s. They can receive and transmit standard frames with 11-bit identifiers as well as
extended frames with 29-bit identifiers. Each CAN has three transmit mailboxes, two receive
FIFOS with 3 stages and 28 shared scalable filter banks (all of them can be used even if one

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CAN is used). The 256 bytes of SRAM which are allocated for each CAN are not shared
with any other peripheral.

3.28 Universal serial bus on-the-go full-speed (OTG_FS)

The devices embed an USB OTG full-speed device/host/OTG peripheral with integrated
transceivers. The USB OTG FS peripheral is compliant with the USB 2.0 specification and
with the OTG 1.0 specification. It has software-configurable endpoint setting and supports
suspend/resume. The USB OTG full-speed controller requires a dedicated 48 MHz clock
that is generated by a PLL connected to the HSE oscillator. The major features are:
• Combined Rx and Tx FIFO size of 320 × 35 bits with dynamic FIFO sizing
• Supports the session request protocol (SRP) and host negotiation protocol (HNP)
• 4 bidirectional endpoints
• 8 host channels with periodic OUT support
• HNP/SNP/IP inside (no need for any external resistor)
• For OTG/Host modes, a power switch is needed in case bus-powered devices are
connected
• Internal FS OTG PHY support

3.29 Universal serial bus on-the-go high-speed (OTG_HS)

The STM32F21x devices embed a USB OTG high-speed (up to 480 Mb/s) device/host/OTG
peripheral. The USB OTG HS supports both full-speed and high-speed operations. It
integrates the transceivers for full-speed operation (12 MB/s) and features a UTMI low-pin
interface (ULPI) for high-speed operation (480 MB/s). When using the USB OTG HS in HS
mode, an external PHY device connected to the ULPI is required.
The USB OTG HS peripheral is compliant with the USB 2.0 specification and with the OTG
1.0 specification. It has software-configurable endpoint setting and supports
suspend/resume. The USB OTG full-speed controller requires a dedicated 48 MHz clock
that is generated by a PLL connected to the HSE oscillator. The major features are:
• Combined Rx and Tx FIFO size of 1024× 35 bits with dynamic FIFO sizing
• Supports the session request protocol (SRP) and host negotiation protocol (HNP)
• 6 bidirectional endpoints
• 12 host channels with periodic OUT support
• Internal FS OTG PHY support
• External HS or HS OTG operation supporting ULPI in SDR mode. The OTG PHY is
connected to the microcontroller ULPI port through 12 signals. It can be clocked using
the 60 MHz output.
• Internal USB DMA
• HNP/SNP/IP inside (no need for any external resistor)
• For OTG/Host modes, a power switch is needed in case bus-powered devices are
connected

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3.30 Audio PLL (PLLI2S)

The devices feature an additional dedicated PLL for audio I2S application. It allows to
achieve error-free I2S sampling clock accuracy without compromising on the CPU
performance, while using USB peripherals.
The PLLI2S configuration can be modified to manage an I2S sample rate change without
disabling the main PLL (PLL) used for CPU, USB and Ethernet interfaces.
The audio PLL can be programmed with very low error to obtain sampling rates ranging
from 8 kHz to 192 kHz.
In addition to the audio PLL, a master clock input pin can be used to synchronize the I2S
flow with an external PLL (or Codec output).

3.31 Digital camera interface (DCMI)

The camera interface is not available in STM32F215xx devices.
STM32F217xx products embed a camera interface that can connect with camera modules
and CMOS sensors through an 8-bit to 14-bit parallel interface, to receive video data. The
camera interface can sustain up to 27 Mbyte/s at 27 MHz or 48 Mbyte/s at 48 MHz. It
features:
• Programmable polarity for the input pixel clock and synchronization signals
• Parallel data communication can be 8-, 10-, 12- or 14-bit
• Supports 8-bit progressive video monochrome or raw Bayer format, YCbCr 4:2:2
progressive video, RGB 565 progressive video or compressed data (like JPEG)
• Supports continuous mode or snapshot (a single frame) mode
• Capability to automatically crop the image

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3.31.1 Cryptographic acceleration

The STM32F215xx and STM32F217xx devices embed a cryptographic accelerator. This
cryptographic accelerator provides a set of hardware acceleration for the advanced
cryptographic algorithms usually needed to provide confidentiality, authentication, data
integrity and non repudiation when exchanging messages with a peer.
• These algorithms consists of:
Encryption/Decryption
– DES/TDES (data encryption standard/triple data encryption standard): ECB
(electronic codebook) and CBC (cipher block chaining) chaining algorithms, 64-,
128- or 192-bit key
– AES (advanced encryption standard): ECB, CBC and CTR (counter mode)
chaining algorithms, 128, 192 or 256-bit key
Universal hash
– SHA-1 (secure hash algorithm)
– MD5
• It also provides a true random number generator that deliver 32-bit random numbers
produced by an integrated analog circuit.

3.32 True random number generator (RNG)

All STM32F2xxx products embed a true RNG that delivers 32-bit random numbers
produced by an integrated analog circuit.

3.33 GPIOs (general-purpose inputs/outputs)

Each of the GPIO pins can be configured by software as output (push-pull or open-drain,
with or without pull-up or pull-down), as input (floating, with or without pull-up or pull-down)
or as peripheral alternate function. Most of the GPIO pins are shared with digital or analog
alternate functions. All GPIOs are high-current-capable and have speed selection to better
manage internal noise, power consumption and electromagnetic emission.
The I/O alternate function configuration can be locked if needed by following a specific
sequence in order to avoid spurious writing to the I/Os registers.
To provide fast I/O handling, the GPIOs are on the fast AHB1 bus with a clock up to
120 MHz that leads to a maximum I/O toggling speed of 60 MHz.

3.34 ADCs (analog-to-digital converters)

Three 12-bit analog-to-digital converters are embedded and each ADC shares up to 16
external channels, performing conversions in the single-shot or scan mode. In scan mode,
automatic conversion is performed on a selected group of analog inputs.
Additional logic functions embedded in the ADC interface allow:
• Simultaneous sample and hold
• Interleaved sample and hold

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The ADC can be served by the DMA controller. An analog watchdog feature allows very
precise monitoring of the converted voltage of one, some or all selected channels. An
interrupt is generated when the converted voltage is outside the programmed thresholds.
The events generated by the timers TIM1, TIM2, TIM3, TIM4, TIM5 and TIM8 can be
internally connected to the ADC start trigger and injection trigger, respectively, to allow the
application to synchronize A/D conversion and timers.

3.35 DAC (digital-to-analog converter)

The two 12-bit buffered DAC channels can be used to convert two digital signals into two
analog voltage signal outputs. The design structure is composed of integrated resistor
strings and an amplifier in inverting configuration.
This dual digital Interface supports the following features:
• two DAC converters: one for each output channel
• 8-bit or 12-bit monotonic output
• left or right data alignment in 12-bit mode
• synchronized update capability
• noise-wave generation
• triangular-wave generation
• dual DAC channel independent or simultaneous conversions
• DMA capability for each channel
• external triggers for conversion
• input voltage reference VREF+
Eight DAC trigger inputs are used in the device. The DAC channels are triggered through
the timer update outputs that are also connected to different DMA streams.

3.36 Temperature sensor

The temperature sensor has to generate a voltage that varies linearly with temperature. The
conversion range is between 1.8 and 3.6 V. The temperature sensor is internally connected
to the ADC1_IN16 input channel which is used to convert the sensor output voltage into a
digital value.
As the offset of the temperature sensor varies from chip to chip due to process variation, the
internal temperature sensor is mainly suitable for applications that detect temperature
changes instead of absolute temperatures. If an accurate temperature reading is needed,
then an external temperature sensor part should be used.

3.37 Serial wire JTAG debug port (SWJ-DP)

The ARM SWJ-DP interface is embedded, and is a combined JTAG and serial wire debug
port that enables either a serial wire debug or a JTAG probe to be connected to the target.
The JTAG TMS and TCK pins are shared with SWDIO and SWCLK, respectively, and a
specific sequence on the TMS pin is used to switch between JTAG-DP and SW-DP.

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Functional overview STM32F21xxx

3.38 Embedded Trace Macrocell™

The ARM Embedded Trace Macrocell provides a greater visibility of the instruction and data
flow inside the CPU core by streaming compressed data at a very high rate from the
STM32F21x through a small number of ETM pins to an external hardware trace port
analyzer (TPA) device. The TPA is connected to a host computer using USB, Ethernet, or
any other high-speed channel. Real-time instruction and data flow activity can be recorded
and then formatted for display on the host computer that runs the debugger software. TPA
hardware is commercially available from common development tool vendors.
The Embedded Trace Macrocell operates with third party debugger software tools.

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4 Pinouts and pin description

Figure 9. STM32F21x LQFP64 pinout

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Pinouts and pin description STM32F21xxx

Figure 10. STM32F21x LQFP100 pinout

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Figure 11. STM32F21x LQFP144 pinout

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AIE

1. RFU means “reserved for future use”. This pin can be tied to VDD,VSS or left unconnected.
2. The above figure shows the package top view.

DocID17050 Rev 13 43/180

179
Pinouts and pin description STM32F21xxx

Figure 12. STM32F21x LQFP176 pinout

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AIE

1. RFU means “reserved for future use”. This pin can be tied to VDD,VSS or left unconnected.
2. The above figure shows the package top view.

44/180 DocID17050 Rev 13

STM32F21xxx Pinouts and pin description

Figure 13. STM32F21x UFBGA176 ballout

              

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AIC

1. RFU means “reserved for future use”. This pin can be tied to VDD,VSS or left unconnected.
2. The above figure shows the package top view.

Table 6. Legend/abbreviations used in the pinout table

Name Abbreviation Definition

Unless otherwise specified in brackets below the pin name, the pin function during and after
Pin name
reset is the same as the actual pin name
S Supply pin
Pin type I Input only pin
I/O Input/ output pin
FT 5 V tolerant I/O
TTa 3.3 V tolerant I/O
I/O structure
B Dedicated BOOT0 pin
RST Bidirectional reset pin with embedded weak pull-up resistor

Notes Unless otherwise specified by a note, all I/Os are set as floating inputs during and after reset

Alternate
Functions selected through GPIOx_AFR registers
functions

Additional
Functions directly selected/enabled through peripheral registers
functions

DocID17050 Rev 13 45/180

179
Pinouts and pin description STM32F21xxx

Table 7. STM32F21x pin and ball definitions

Pins

I / O structure
Pin name

Pin type
UFBGA176
Additional

Note
LQFP100

LQFP144

LQFP176
LQFP64

(function after Alternate functions

functions
reset)(1)

TRACECLK, FSMC_A23,
- 1 1 1 A2 PE2 I/O FT - -
ETH_MII_TXD3, EVENTOUT
TRACED0, FSMC_A19,
- 2 2 2 A1 PE3 I/O FT - -
EVENTOUT
TRACED1, FSMC_A20,
- 3 3 3 B1 PE4 I/O FT - -
DCMI_D4/ EVENTOUT
TRACED2, FSMC_A21,
- 4 4 4 B2 PE5 I/O FT - TIM9_CH1, DCMI_D6, -
EVENTOUT
TRACED3, FSMC_A22,
- 5 5 5 B3 PE6 I/O FT - TIM9_CH2, DCMI_D7, -
EVENTOUT
1 6 6 6 C1 VBAT S - - - -
- - - 7 D2 PI8 I/O FT (2)(3) EVENTOUT RTC_AF2
2 7 7 8 D1 PC13 I/O FT (2)(3)
EVENTOUT RTC_AF1
PC14/OSC32_IN
3 8 8 9 E1 I/O FT (2)(3) EVENTOUT OSC32_IN(4)
(PC14)
PC15/
4 9 9 10 F1 OSC32_OUT I/O FT (2)(3) EVENTOUT OSC32_OUT(4)
(PC15)
- - - 11 D3 PI9 I/O FT - CAN1_RX, EVENTOUT -
- - - 12 E3 PI10 I/O FT - ETH_MII_RX_ER, EVENTOUT -
OTG_HS_ULPI_DIR,
- - - 13 E4 PI11 I/O FT - -
EVENTOUT
- - - 14 F2 VSS S - - -
- - - 15 F3 VDD S - - -
FSMC_A0, I2C2_SDA,
- - 10 16 E2 PF0 I/O FT - -
EVENTOUT
FSMC_A1, I2C2_SCL,
- - 11 17 H3 PF1 I/O FT - -
EVENTOUT
FSMC_A2, I2C2_SMBA,
- - 12 18 H2 PF2 I/O FT - -
EVENTOUT
- - 13 19 J2 PF3 I/O FT (4) FSMC_A3, EVENTOUT ADC3_IN9

46/180 DocID17050 Rev 13

STM32F21xxx Pinouts and pin description

Table 7. STM32F21x pin and ball definitions (continued)

Pins

I / O structure
Pin name

Pin type
UFBGA176
Additional

Note
LQFP100

LQFP144

LQFP176
LQFP64

(function after Alternate functions

functions
reset)(1)

- - 14 20 J3 PF4 I/O FT (4) FSMC_A4, EVENTOUT ADC3_IN14

- - 15 21 K3 PF5 I/O FT (4)
FSMC_A5, EVENTOUT ADC3_IN15
- 10 16 22 G2 VSS S - - - -
- 11 17 23 G3 VDD S - - - -

(4) TIM10_CH1, FSMC_NIORD,

- - 18 24 K2 PF6 I/O FT ADC3_IN4
EVENTOUT

(4) TIM11_CH1, FSMC_NREG,

- - 19 25 K1 PF7 I/O FT ADC3_IN5
EVENTOUT

(4) TIM13_CH1, FSMC_NIOWR,

- - 20 26 L3 PF8 I/O FT ADC3_IN6
EVENTOUT

(4) TIM14_CH1, FSMC_CD,

- - 21 27 L2 PF9 I/O FT ADC3_IN7
EVENTOUT
(4)
- - 22 28 L1 PF10 I/O FT FSMC_INTR, EVENTOUT ADC3_IN8
PH0/OSC_IN
5 12 23 29 G1 I/O FT - EVENTOUT OSC_IN(4)
(PH0)
PH1/OSC_OUT
6 13 24 30 H1 I/O FT - EVENTOUT OSC_OUT(4)
(PH1)
7 14 25 31 J1 NRST I/O RST - - -

(4) OTG_HS_ULPI_STP, ADC123_

8 15 26 32 M2 PC0 I/O FT
EVENTOUT IN10

(4) ADC123_
9 16 27 33 M3 PC1 I/O FT ETH_MDC, EVENTOUT
IN11
SPI2_MISO,
(4) ADC123_
10 17 28 34 M4 PC2 I/O FT OTG_HS_ULPI_DIR,
IN12
ETH_MII_TXD2, EVENTOUT
SPI2_MOSI, I2S2_SD,
(4) OTG_HS_ULPI_NXT, ADC123_
11 18 29 35 M5 PC3 I/O FT
ETH_MII_TX_CLK, IN13
EVENTOUT
- 19 30 36 - VDD S - - - -
12 20 31 37 M1 VSSA S - - - -
- - - - N1 VREF- S - - - -
- 21 32 38 P1 VREF+ S - - - -

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179
Pinouts and pin description STM32F21xxx

Table 7. STM32F21x pin and ball definitions (continued)

Pins

I / O structure
Pin name

Pin type
UFBGA176
Additional

Note
LQFP100

LQFP144

LQFP176
LQFP64

(function after Alternate functions

functions
reset)(1)

13 22 33 39 R1 VDDA S - - - -
USART2_CTS, UART4_TX,
ETH_MII_CRS,
PA0/WKUP ADC123_IN0,
14 23 34 40 N3 I/O FT (4)(5) TIM2_CH1_ETR,
(PA0) WKUP
TIM5_CH1, TIM8_ETR,
EVENTOUT
USART2_RTS, UART4_RX,
(4) ETH_RMII_REF_CLK,
15 24 35 41 N2 PA1 I/O FT ADC123_IN1
ETH_MII_RX_CLK, TIM5_CH2,
TIM2_CH2, EVENTOUT
USART2_TX,TIM5_CH3,
(4)
16 25 36 42 P2 PA2 I/O FT TIM9_CH1, TIM2_CH3, ADC123_IN2
ETH_MDIO, EVENTOUT
- - - 43 F4 PH2 I/O FT - ETH_MII_CRS, EVENTOUT -
- - - 44 G4 PH3 I/O FT - ETH_MII_COL, EVENTOUT -
I2C2_SCL,
- - - 45 H4 PH4 I/O FT - OTG_HS_ULPI_NXT, -
EVENTOUT
- - - 46 J4 PH5 I/O FT - I2C2_SDA, EVENTOUT -
USART2_RX, TIM5_CH4,
(4) TIM9_CH2, TIM2_CH4,
17 26 37 47 R2 PA3 I/O FT ADC123_IN3
OTG_HS_ULPI_D0,
ETH_MII_COL, EVENTOUT
18 27 38 48 - VSS S - - - -
L4 REGOFF I/O - - - -
19 28 39 49 K4 VDD S - - - -
SPI1_NSS, SPI3_NSS,
(4) USART2_CK, DCMI_HSYNC, ADC12_IN4,
20 29 40 50 N4 PA4 I/O TTa
OTG_HS_SOF, I2S3_WS, DAC_OUT1
EVENTOUT
SPI1_SCK,
(4) OTG_HS_ULPI_CK, ADC12_IN5
21 30 41 51 P4 PA5 I/O TTa
TIM2_CH1_ETR, TIM8_CH1N, /DAC_OUT2
EVENTOUT

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STM32F21xxx Pinouts and pin description

Table 7. STM32F21x pin and ball definitions (continued)

Pins

I / O structure
Pin name

Pin type
UFBGA176
Additional

Note
LQFP100

LQFP144

LQFP176
LQFP64

(function after Alternate functions

functions
reset)(1)

SPI1_MISO, TIM8_BKIN,
(4) TIM13_CH1, DCMI_PIXCLK,
22 31 42 52 P3 PA6 I/O FT ADC12_IN6
TIM3_CH1, TIM1_BKIN,
EVENTOUT
SPI1_MOSI, TIM8_CH1N,
TIM14_CH1, TIM3_CH2,
(4)
23 32 43 53 R3 PA7 I/O FT ETH_MII_RX_DV, TIM1_CH1N, ADC12_IN7
ETH_RMII_CRS_DV,
EVENTOUT

(4) ETH_RMII_RXD0,/
24 33 44 54 N5 PC4 I/O FT ADC12_IN14
ETH_MII_RXD0, EVENTOUT

(4) ETH_RMII_RXD1,
25 34 45 55 P5 PC5 I/O FT ADC12_IN15
ETH_MII_RXD1, EVENTOUT
TIM3_CH3, TIM8_CH2N,
(4) OTG_HS_ULPI_D1,
26 35 46 56 R5 PB0 I/O FT ADC12_IN8
ETH_MII_RXD2, TIM1_CH2N,
EVENTOUT
TIM3_CH4, TIM8_CH3N,
(4) OTG_HS_ULPI_D2,
27 36 47 57 R4 PB1 I/O FT ADC12_IN9
ETH_MII_RXD3, TIM1_CH3N,
EVENTOUT
PB2/BOOT1
28 37 48 58 M6 I/O FT - EVENTOUT -
(PB2)
- - 49 59 R6 PF11 I/O FT - DCMI_D12, EVENTOUT -
- - 50 60 P6 PF12 I/O FT - FSMC_A6, EVENTOUT -
- - 51 61 M8 VSS S - - - -
- - 52 62 N8 VDD S - - - -
- - 53 63 N6 PF13 I/O FT - FSMC_A7, EVENTOUT -
- - 54 64 R7 PF14 I/O FT - FSMC_A8, EVENTOUT -
- - 55 65 P7 PF15 I/O FT - FSMC_A9, EVENTOUT -
- - 56 66 N7 PG0 I/O FT - FSMC_A10, EVENTOUT -
- - 57 67 M7 PG1 I/O FT - FSMC_A11, EVENTOUT -
FSMC_D4, TIM1_ETR,
- 38 58 68 R8 PE7 I/O FT - -
EVENTOUT

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179
Pinouts and pin description STM32F21xxx

Table 7. STM32F21x pin and ball definitions (continued)

Pins

I / O structure
Pin name

Pin type
UFBGA176
Additional

Note
LQFP100

LQFP144

LQFP176
LQFP64

(function after Alternate functions

functions
reset)(1)

FSMC_D5, TIM1_CH1N,
- 39 59 69 P8 PE8 I/O FT - -
EVENTOUT
FSMC_D6, TIM1_CH1,
- 40 60 70 P9 PE9 I/O FT - -
EVENTOUT
- - 61 71 M9 VSS S - - - -
- - 62 72 N9 VDD S - - - -
FSMC_D7, TIM1_CH2N,
- 41 63 73 R9 PE10 I/O FT - -
EVENTOUT
FSMC_D8,TIM1_CH2,
- 42 64 74 P10 PE11 I/O FT - -
EVENTOUT
FSMC_D9,TIM1_CH3N,
- 43 65 75 R10 PE12 I/O FT - -
EVENTOUT
FSMC_D10,TIM1_CH3,
- 44 66 76 N11 PE13 I/O FT - -
EVENTOUT
FSMC_D11,TIM1_CH4,
- 45 67 77 P11 PE14 I/O FT - -
EVENTOUT
FSMC_D12,TIM1_BKIN,
- 46 68 78 R11 PE15 I/O FT - -
EVENTOUT
SPI2_SCK, I2S2_SCK,
I2C2_SCL, USART3_TX,
29 47 69 79 R12 PB10 I/O FT - OTG_HS_ULPI_D3, -
ETH_MII_RX_ER, TIM2_CH3,
EVENTOUT
I2C2_SDA,USART3_RX,
OTG_HS_ULPI_D4,
30 48 70 80 R13 PB11 I/O FT - ETH_RMII_TX_EN, -
ETH_MII_TX_EN, TIM2_CH4,
EVENTOUT
31 49 71 81 M10 VCAP_1 S - - -
32 50 72 82 N10 VDD S - - -
I2C2_SMBA, TIM12_CH1,
- - - 83 M11 PH6 I/O FT - -
ETH_MII_RXD2, EVENTOUT
I2C3_SCL, ETH_MII_RXD3,
- - - 84 N12 PH7 I/O FT - -
EVENTOUT

50/180 DocID17050 Rev 13

STM32F21xxx Pinouts and pin description

Table 7. STM32F21x pin and ball definitions (continued)

Pins

I / O structure
Pin name

Pin type
UFBGA176
Additional

Note
LQFP100

LQFP144

LQFP176
LQFP64

(function after Alternate functions

functions
reset)(1)

I2C3_SDA, DCMI_HSYNC,
- - - 85 M12 PH8 I/O FT - -
EVENTOUT
I2C3_SMBA, TIM12_CH2,
- - - 86 M13 PH9 I/O FT - -
DCMI_D0, EVENTOUT
TIM5_CH1, DCMI_D1,
- - - 87 L13 PH10 I/O FT - -
EVENTOUT
TIM5_CH2, DCMI_D2,
- - - 88 L12 PH11 I/O FT - -
EVENTOUT
TIM5_CH3, DCMI_D3,
- - - 89 K12 PH12 I/O FT - -
EVENTOUT
- - - 90 H12 VSS S - - - -
- - - 91 J12 VDD S - - - -
SPI2_NSS,I2S2_WS,
I2C2_SMBA,
USART3_CK, TIM1_BKIN,
33 51 73 92 P12 PB12 I/O FT - CAN2_RX, OTG_HS_ULPI_D5, -
ETH_RMII_TXD0,
ETH_MII_TXD0, OTG_HS_ID,
EVENTOUT
SPI2_SCK, I2S2_SCK,
USART3_CTS,
TIM1_CH1N,CAN2_TX, OTG_HS_
34 52 74 93 P13 PB13 I/O FT -
OTG_HS_ULPI_D6, VBUS
ETH_RMII_TXD1,
ETH_MII_TXD1, EVENTOUT
SPI2_MISO, TIM1_CH2N,
TIM12_CH1, OTG_HS_DM
35 53 75 94 R14 PB14 I/O FT - -
USART3_RTS, TIM8_CH2N,
EVENTOUT
SPI2_MOSI, I2S2_SD,
TIM1_CH3N, TIM8_CH3N,
36 54 76 95 R15 PB15 I/O FT - -
TIM12_CH2, OTG_HS_DP,
RTC_50Hz, EVENTOUT
FSMC_D13, USART3_TX,
- 55 77 96 P15 PD8 I/O FT - -
EVENTOUT
FSMC_D14, USART3_RX,
- 56 78 97 P14 PD9 I/O FT - -
EVENTOUT

DocID17050 Rev 13 51/180

179
Pinouts and pin description STM32F21xxx

Table 7. STM32F21x pin and ball definitions (continued)

Pins

I / O structure
Pin name

Pin type
UFBGA176
Additional

Note
LQFP100

LQFP144

LQFP176
LQFP64

(function after Alternate functions

functions
reset)(1)

FSMC_D15, USART3_CK,
- 57 79 98 N15 PD10 I/O FT - -
EVENTOUT
FSMC_A16,USART3_CTS,
- 58 80 99 N14 PD11 I/O FT - -
EVENTOUT
FSMC_A17,TIM4_CH1,
- 59 81 100 N13 PD12 I/O FT - -
USART3_RTS, EVENTOUT
FSMC_A18,TIM4_CH2,
- 60 82 101 M15 PD13 I/O FT - -
EVENTOUT
- - 83 102 - VSS S - - -
- - 84 103 J13 VDD S - - -
FSMC_D0,TIM4_CH3,
- 61 85 104 M14 PD14 I/O FT - -
EVENTOUT
FSMC_D1,TIM4_CH4,
- 62 86 105 L14 PD15 I/O FT - -
EVENTOUT
- - 87 106 L15 PG2 I/O FT - FSMC_A12, EVENTOUT -
- - 88 107 K15 PG3 I/O FT - FSMC_A13, EVENTOUT -
- - 89 108 K14 PG4 I/O FT - FSMC_A14, EVENTOUT -
- - 90 109 K13 PG5 I/O FT - FSMC_A15, EVENTOUT -
- - 91 110 J15 PG6 I/O FT - FSMC_INT2, EVENTOUT -
FSMC_INT3,USART6_CK,
- - 92 111 J14 PG7 I/O FT - -
EVENTOUT
USART6_RTS,
- - 93 112 H14 PG8 I/O FT - -
ETH_PPS_OUT, EVENTOUT
- - 94 113 G12 VSS S - - - -
- - 95 114 H13 VDD S - - - -
I2S2_MCK,
TIM8_CH1,SDIO_D6,
37 63 96 115 H15 PC6 I/O FT - USART6_TX, -
DCMI_D0,TIM3_CH1,
EVENTOUT

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STM32F21xxx Pinouts and pin description

Table 7. STM32F21x pin and ball definitions (continued)

Pins

I / O structure
Pin name

Pin type
UFBGA176
Additional

Note
LQFP100

LQFP144

LQFP176
LQFP64

(function after Alternate functions

functions
reset)(1)

I2S3_MCK,
TIM8_CH2,SDIO_D7,
38 64 97 116 G15 PC7 I/O FT - USART6_RX, -
DCMI_D1,TIM3_CH2,
EVENTOUT
TIM8_CH3,SDIO_D0,
39 65 98 117 G14 PC8 I/O FT - TIM3_CH3, USART6_CK, -
DCMI_D2, EVENTOUT
I2S2_CKIN, I2S3_CKIN,
MCO2, TIM8_CH4,SDIO_D1,
40 66 99 118 F14 PC9 I/O FT - -
I2C3_SDA, DCMI_D3,
TIM3_CH4, EVENTOUT
MCO1, USART1_CK,
41 67 100 119 F15 PA8 I/O FT - TIM1_CH1, I2C3_SCL, -
OTG_FS_SOF, EVENTOUT
USART1_TX, TIM1_CH2,
OTG_FS_
42 68 101 120 E15 PA9 I/O FT - I2C3_SMBA, DCMI_D0,
VBUS
EVENTOUT
USART1_RX, TIM1_CH3,
43 69 102 121 D15 PA10 I/O FT - OTG_FS_ID,DCMI_D1, -
EVENTOUT
USART1_CTS, CAN1_RX,
44 70 103 122 C15 PA11 I/O FT - TIM1_CH4, OTG_FS_DM, -
EVENTOUT
USART1_RTS, CAN1_TX,
45 71 104 123 B15 PA12 I/O FT - TIM1_ETR, OTG_FS_DP, -
EVENTOUT
PA13
46 72 105 124 A15 I/O FT - JTMS-SWDIO, EVENTOUT -
(JTMS-SWDIO)
47 73 106 125 F13 VCAP_2 S - - - -
- 74 107 126 F12 VSS S - - - -
48 75 108 127 G13 VDD S - - - -
TIM8_CH1N, CAN1_TX,
- - - 128 E12 PH13 I/O FT - -
EVENTOUT
TIM8_CH2N, DCMI_D4,
- - - 129 E13 PH14 I/O FT - -
EVENTOUT

DocID17050 Rev 13 53/180

179
Pinouts and pin description STM32F21xxx

Table 7. STM32F21x pin and ball definitions (continued)

Pins

I / O structure
Pin name

Pin type
UFBGA176
Additional

Note
LQFP100

LQFP144

LQFP176
LQFP64

(function after Alternate functions

functions
reset)(1)

TIM8_CH3N, DCMI_D11,
- - - 130 D13 PH15 I/O FT - -
EVENTOUT
TIM5_CH4, SPI2_NSS,
- - - 131 E14 PI0 I/O FT - I2S2_WS, DCMI_D13, -
EVENTOUT
SPI2_SCK, I2S2_SCK,
- - - 132 D14 PI1 I/O FT - -
DCMI_D8, EVENTOUT
TIM8_CH4,SPI2_MISO,
- - - 133 C14 PI2 I/O FT - -
DCMI_D9, EVENTOUT
TIM8_ETR, SPI2_MOSI,
- - - 134 C13 PI3 I/O FT - I2S2_SD, DCMI_D10, -
EVENTOUT
- - - 135 D9 VSS S - - - -
- - - 136 C9 VDD S - - - -
PA14
49 76 109 137 A14 I/O FT - JTCK-SWCLK, EVENTOUT -
(JTCK-SWCLK)
JTDI, SPI3_NSS,
PA15
50 77 110 138 A13 I/O FT - I2S3_WS,TIM2_CH1_ETR, -
(JTDI)
SPI1_NSS/ EVENTOUT
SPI3_SCK, I2S3_SCK,
UART4_TX, SDIO_D2,
51 78 111 139 B14 PC10 I/O FT - -
DCMI_D8, USART3_TX,
EVENTOUT
UART4_RX, SPI3_MISO,
SDIO_D3,
52 79 112 140 B13 PC11 I/O FT - -
DCMI_D4,USART3_RX,
EVENTOUT
UART5_TX,SDIO_CK,
DCMI_D9, SPI3_MOSI,
53 80 113 141 A12 PC12 I/O FT - -
I2S3_SD, USART3_CK,
EVENTOUT
FSMC_D2,CAN1_RX,
- 81 114 142 B12 PD0 I/O FT - -
EVENTOUT
FSMC_D3, CAN1_TX,
- 82 115 143 C12 PD1 I/O FT - -
EVENTOUT

54/180 DocID17050 Rev 13

STM32F21xxx Pinouts and pin description

Table 7. STM32F21x pin and ball definitions (continued)

Pins

I / O structure
Pin name

Pin type
UFBGA176
Additional

Note
LQFP100

LQFP144

LQFP176
LQFP64

(function after Alternate functions

functions
reset)(1)

TIM3_ETR,UART5_RX
54 83 116 144 D12 PD2 I/O FT - SDIO_CMD, DCMI_D11, -
EVENTOUT
FSMC_CLK,USART2_CTS,
- 84 117 145 D11 PD3 I/O FT - -
EVENTOUT
FSMC_NOE,USART2_RTS,
- 85 118 146 D10 PD4 I/O FT - -
EVENTOUT
FSMC_NWE,USART2_TX,
- 86 119 147 C11 PD5 I/O FT - -
EVENTOUT
- - 120 148 D8 VSS S - - -
- - 121 149 C8 VDD S - - -
FSMC_NWAIT,USART2_RX,
- 87 122 150 B11 PD6 I/O FT - -
EVENTOUT
USART2_CK,FSMC_NE1,
- 88 123 151 A11 PD7 I/O FT - -
FSMC_NCE2, EVENTOUT
USART6_RX,
- - 124 152 C10 PG9 I/O FT - FSMC_NE2,FSMC_NCE3, -
EVENTOUT
FSMC_NCE4_1, FSMC_NE3,
- - 125 153 B10 PG10 I/O FT - -
EVENTOUT
FSMC_NCE4_2,
ETH_MII_TX_EN,
- - 126 154 B9 PG11 I/O FT - -
ETH _RMII_TX_EN,
EVENTOUT
FSMC_NE4, USART6_RTS,
- - 127 155 B8 PG12 I/O FT - -
EVENTOUT
FSMC_A24, USART6_CTS,
- - 128 156 A8 PG13 I/O FT - ETH_MII_TXD0, -
ETH_RMII_TXD0, EVENTOUT
FSMC_A25, USART6_TX,
- - 129 157 A7 PG14 I/O FT - ETH_MII_TXD1, -
ETH_RMII_TXD1, EVENTOUT
- - 130 158 D7 VSS S - - - -
- - 131 159 C7 VDD S - - - -

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Pinouts and pin description STM32F21xxx

Table 7. STM32F21x pin and ball definitions (continued)

Pins

I / O structure
Pin name

Pin type
UFBGA176
Additional

Note
LQFP100

LQFP144

LQFP176
LQFP64

(function after Alternate functions

functions
reset)(1)

USART6_CTS, DCMI_D13,
- - 132 160 B7 PG15 I/O FT - -
EVENTOUT
JTDO/TRACESWO,
PB3 SPI3_SCK, I2S3_SCK,
55 89 133 161 A10 I/O FT - -
(JTDO/TRACESWO) TIM2_CH2, SPI1_SCK,
EVENTOUT
NJTRST, SPI3_MISO,
56 90 134 162 A9 PB4 I/O FT - TIM3_CH1, SPI1_MISO, -
EVENTOUT
I2C1_SMBA, CAN2_RX,
OTG_HS_ULPI_D7,
ETH_PPS_OUT,TIM3_CH2,
57 91 135 163 A6 PB5 I/O FT - -
SPI1_MOSI, SPI3_MOSI,
DCMI_D10, I2S3_SD,
EVENTOUT
I2C1_SCL, TIM4_CH1,
CAN2_TX,
58 92 136 164 B6 PB6 I/O FT - -
DCMI_D5,USART1_TX,
EVENTOUT
I2C1_SDA, FSMC_NL(6),
59 93 137 165 B5 PB7 I/O FT - DCMI_VSYNC, USART1_RX, -
TIM4_CH2, EVENTOUT
60 94 138 166 D6 BOOT0 I B - - VPP
TIM4_CH3,SDIO_D4,
TIM10_CH1, DCMI_D6,
61 95 139 167 A5 PB8 I/O FT - -
ETH_MII_TXD3, I2C1_SCL,
CAN1_RX, EVENTOUT
SPI2_NSS, I2S2_WS,
TIM4_CH4, TIM11_CH1,
62 96 140 168 B4 PB9 I/O FT - SDIO_D5, DCMI_D7, -
I2C1_SDA, CAN1_TX,
EVENTOUT
TIM4_ETR, FSMC_NBL0,
- 97 141 169 A4 PE0 I/O FT - -
DCMI_D2, EVENTOUT
FSMC_NBL1, DCMI_D3,
- 98 142 170 A3 PE1 I/O FT - -
EVENTOUT
- - - - D5 VSS S - - -

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STM32F21xxx Pinouts and pin description

Table 7. STM32F21x pin and ball definitions (continued)

Pins

I / O structure
Pin name

Pin type
UFBGA176
Additional

Note
LQFP100

LQFP144

LQFP176
LQFP64

(function after Alternate functions

functions
reset)(1)

63 - - - - VSS S - - - -
- 99 143 171 C6 RFU - - (7)
- -
64 100 144 172 C5 VDD S - - - -
TIM8_BKIN, DCMI_D5,
- - - 173 D4 PI4 I/O FT - -
EVENTOUT
TIM8_CH1, DCMI_VSYNC,
- - - 174 C4 PI5 I/O FT - -
EVENTOUT
TIM8_CH2, DCMI_D6,
- - - 175 C3 PI6 I/O FT - -
EVENTOUT
TIM8_CH3, DCMI_D7,
- - - 176 C2 PI7 I/O FT - -
EVENTOUT
1. Function availability depends on the chosen device.
2. PC13, PC14, PC15 and PI8 are supplied through the power switch. Since the switch only sinks a limited amount of current
(3 mA), the use of GPIOs PC13 to PC15 and PI8 in output mode is limited: the speed should not exceed 2 MHz with a
maximum load of 30 pF and these I/Os must not be used as a current source (e.g. to drive an LED).
3. Main function after the first backup domain power-up. Later on, it depends on the contents of the RTC registers even after
reset (because these registers are not reset by the main reset). For details on how to manage these I/Os, refer to the RTC
register description sections in the STM32F20x and STM32F21x reference manual, available from the STMicroelectronics
website www.st.com.
4. FT = 5 V tolerant except when in analog mode or oscillator mode (for PC14, PC15, PH0 and PH1).
5. If the device is delivered in an UFBGA176 package and if the REGOFF pin is set to VDD (Regulator OFF), then PA0 is used
as an internal Reset (active low).
6. FSMC_NL pin is also named FSMC_NADV on memory devices.
7. RFU means “reserved for future use”. This pin can be tied to VDD,VSS or left unconnected.

Table 8. FSMC pin definition

FSMC
Pins LQFP100
CF NOR/PSRAM/SRAM NOR/PSRAM Mux NAND 16 bit

PE2 - A23 A23 - Yes

PE3 - A19 A19 - Yes
PE4 - A20 A20 - Yes
PE5 - A21 A21 - Yes
PE6 - A22 A22 - Yes
PF0 A0 A0 - - -
PF1 A1 A1 - - -

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Pinouts and pin description STM32F21xxx

Table 8. FSMC pin definition (continued)

FSMC
Pins LQFP100
CF NOR/PSRAM/SRAM NOR/PSRAM Mux NAND 16 bit

PF2 A2 A2 - - -
PF3 A3 A3 - - -
PF4 A4 A4 - - -
PF5 A5 A5 - - -
PF6 NIORD - - - -
PF7 NREG - - - -
PF8 NIOWR - - - -
PF9 CD - - - -
PF10 INTR - - - -
PF12 A6 A6 - - -
PF13 A7 A7 - - -
PF14 A8 A8 - - -
PF15 A9 A9 - - -
PG0 A10 A10 - - -
PG1 - A11 - - -
PE7 D4 D4 DA4 D4 Yes
PE8 D5 D5 DA5 D5 Yes
PE9 D6 D6 DA6 D6 Yes
PE10 D7 D7 DA7 D7 Yes
PE11 D8 D8 DA8 D8 Yes
PE12 D9 D9 DA9 D9 Yes
PE13 D10 D10 DA10 D10 Yes
PE14 D11 D11 DA11 D11 Yes
PE15 D12 D12 DA12 D12 Yes
PD8 D13 D13 DA13 D13 Yes
PD9 D14 D14 DA14 D14 Yes
PD10 D15 D15 DA15 D15 Yes
PD11 - A16 A16 CLE Yes
PD12 - A17 A17 ALE Yes
PD13 - A18 A18 - Yes
PD14 D0 D0 DA0 D0 Yes
PD15 D1 D1 DA1 D1 Yes
PG2 - A12 - - -

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STM32F21xxx Pinouts and pin description

Table 8. FSMC pin definition (continued)

FSMC
Pins LQFP100
CF NOR/PSRAM/SRAM NOR/PSRAM Mux NAND 16 bit

PG3 - A13 - - -
PG4 - A14 - - -
PG5 - A15 - - -
PG6 - - - INT2 -
PG7 - - - INT3 -
PD0 D2 D2 DA2 D2 Yes
PD1 D3 D3 DA3 D3 Yes
PD3 - CLK CLK - Yes
PD4 NOE NOE NOE NOE Yes
PD5 NWE NWE NWE NWE Yes
PD6 NWAIT NWAIT NWAIT NWAIT Yes
PD7 - NE1 NE1 NCE2 Yes
PG9 - NE2 NE2 NCE3 -
PG10 NCE4_1 NE3 NE3 - -
PG11 NCE4_2 - - - -
PG12 - NE4 NE4 - -
PG13 - A24 A24 - -
PG14 - A25 A25 - -
PB7 - NADV NADV - Yes
PE0 - NBL0 NBL0 - Yes
PE1 - NBL1 NBL1 - Yes

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60/10

Pinouts and pin description

Table 9. Alternate function mapping
AF0 AF1 AF2 AF3 AF4 AF5 AF6 AF7 AF8 AF9 AF10 AF11 AF12 AF13
Port AF014 AF15
UART4/5/ CAN1/CAN2/ FSMC/SDIO/
SYS TIM1/2 TIM3/4/5 TIM8/9/10/11 I2C1/I2C2/I2C3 SPI1/SPI2/I2S2 SPI3/I2S3 USART1/2/3 OTG_FS/ OTG_HS ETH DCMI
USART6 TIM12/13/14 OTG_HS

PA0-WKUP - TIM2_CH1_ETR TIM 5_CH1 TIM8_ETR - - USART2_CTS UART4_TX - - ETH_MII_CRS - - - EVENTOUT

ETH_MII
_RX_CLK
PA1 - TIM2_CH2 TIM5_CH2 - - - USART2_RTS UART4_RX - - - - - EVENTOUT
ETH_RMII
_REF_CLK

PA2 - TIM2_CH3 TIM5_CH3 TIM9_CH1 - - USART2_TX - - - ETH_MDIO - - - EVENTOUT

PA3 - TIM2_CH4 TIM5_CH4 TIM9_CH2 - - USART2_RX - - OTG_HS_ULPI_D0 ETH _MII_COL - - - EVENTOUT

SPI3_NSS
PA4 - - - - - SPI1_NSS USART2_CK - - - OTG_HS_SOF DCMI_HSYNC - EVENTOUT
I2S3_WS
OTG_HS_ULPI_C
PA5 - TIM2_CH1_ETR - TIM8_CH1N - SPI1_SCK - - - - - - - - EVENTOUT
K

PA6 - TIM1_BKIN TIM3_CH1 TIM8_BKIN - SPI1_MISO - - - TIM13_CH1 - - - DCMI_PIXCK - EVENTOUT

ETH_MII _RX_DV
Port A PA7 - TIM1_CH1N TIM3_CH2 TIM8_CH1N - SPI1_MOSI - - - TIM14_CH1 - ETH_RMII - - - EVENTOUT
_CRS_DV

PA8 MCO1 TIM1_CH1 - - I2C3_SCL - - USART1_CK - - OTG_FS_SOF - - - - EVENTOUT

PA9 - TIM1_CH2 - - I2C3_SMBA - - USART1_TX - - - - DCMI_D0 - EVENTOUT

DocID17050 Rev 13

PA10 - TIM1_CH3 - - - - - USART1_RX - - OTG_FS_ID - - DCMI_D1 - EVENTOUT

PA11 - TIM1_CH4 - - - - - USART1_CTS - CAN1_RX OTG_FS_DM - - - - EVENTOUT

PA12 - TIM1_ETR - - - - - USART1_RTS - CAN1_TX OTG_FS_DP - - - - EVENTOUT

JTMS-
PA13 - - - - - - - - - - - - - - EVENTOUT
SWDIO
JTCK-
PA14 - - - - - - - - - - - - - - EVENTOUT
SWCLK
TIM 2_CH1 SPI3_NSS
PA15 JTDI - - - SPI1_NSS - - - - - - - - EVENTOUT
TIM 2_ETR I2S3_WS

STM32F21xxx
 Table 9. Alternate function mapping (continued)

STM32F21xxx
AF0 AF1 AF2 AF3 AF4 AF5 AF6 AF7 AF8 AF9 AF10 AF11 AF12 AF13
Port AF014 AF15
UART4/5/ CAN1/CAN2/ FSMC/SDIO/
SYS TIM1/2 TIM3/4/5 TIM8/9/10/11 I2C1/I2C2/I2C3 SPI1/SPI2/I2S2 SPI3/I2S3 USART1/2/3 OTG_FS/ OTG_HS ETH DCMI
USART6 TIM12/13/14 OTG_HS

PB0 - TIM1_CH2N TIM3_CH3 TIM8_CH2N - - - - - - OTG_HS_ULPI_D1 ETH _MII_RXD2 - - - EVENTOUT

PB1 - TIM1_CH3N TIM3_CH4 TIM8_CH3N - - - - - - OTG_HS_ULPI_D2 ETH _MII_RXD3 - - - EVENTOUT

PB2 - - - - - - - - - - - - - - - EVENTOUT

JTDO/ SPI3_SCK
PB3 TIM2_CH2 - - - SPI1_SCK - - - - - - - - EVENTOUT
TRACESWO I2S3_SCK

PB4 JTRST - TIM3_CH1 - - SPI1_MISO SPI3_MISO - - - - - - - - EVENTOUT

SPI3_MOSI
PB5 - - TIM3_CH2 - I2C1_SMBA SPI1_MOSI - - CAN2_RX OTG_HS_ULPI_D7 ETH _PPS_OUT - DCMI_D10 - EVENTOUT
I2S3_SD
PB6 - - TIM4_CH1 - I2C1_SCL - - USART1_TX - CAN2_TX - - - DCMI_D5 - EVENTOUT

PB7 - - TIM4_CH2 - I2C1_SDA - - USART1_RX - - - - FSMC_NL DCMI_VSYNC - EVENTOUT

Port B PB8 - - TIM4_CH3 TIM10_CH1 I2C1_SCL - - - - CAN1_RX - ETH _MII_TXD3 SDIO_D4 DCMI_D6 - EVENTOUT

SPI2_NSS
PB9 - - TIM4_CH4 TIM11_CH1 I2C1_SDA - - - CAN1_TX - - SDIO_D5 DCMI_D7 - EVENTOUT
I2S2_WS
SPI2_SCK
PB10 - TIM2_CH3 - - I2C2_SCL - USART3_TX - - OTG_HS_ULPI_D3 ETH_ MII_RX_ER - - - EVENTOUT
I2S2_SCK
ETH _MII_TX_EN
DocID17050 Rev 13

PB11 - TIM2_CH4 - - I2C2_SDA - - USART3_RX - - OTG_HS_ULPI_D4 ETH - - - EVENTOUT

_RMII_TX_EN
SPI2_NSS ETH _MII_TXD0
PB12 - TIM1_BKIN - - I2C2_SMBA - USART3_CK - CAN2_RX OTG_HS_ULPI_D5 OTG_HS_ID - - EVENTOUT
I2S2_WS ETH _RMII_TXD0
SPI2_SCK ETH _MII_TXD1
PB13 - TIM1_CH1N - - - - USART3_CTS - CAN2_TX OTG_HS_ULPI_D6 - - - EVENTOUT
I2S2_SCK ETH _RMII_TXD1
PB14 - TIM1_CH2N - TIM8_CH2N - SPI2_MISO - USART3_RTS - TIM12_CH1 - - OTG_HS_DM - - EVENTOUT
SPI2_MOSI
PB15 RTC_50Hz TIM1_CH3N - TIM8_CH3N - - - - TIM12_CH2 - - OTG_HS_DP - - EVENTOUT
I2S2_SD

Pinouts and pin description

61/10
 Table 9. Alternate function mapping (continued)
62/10

Pinouts and pin description

AF0 AF1 AF2 AF3 AF4 AF5 AF6 AF7 AF8 AF9 AF10 AF11 AF12 AF13
Port AF014 AF15
UART4/5/ CAN1/CAN2/ FSMC/SDIO/
SYS TIM1/2 TIM3/4/5 TIM8/9/10/11 I2C1/I2C2/I2C3 SPI1/SPI2/I2S2 SPI3/I2S3 USART1/2/3 OTG_FS/ OTG_HS ETH DCMI
USART6 TIM12/13/14 OTG_HS
OTG_HS_ULPI_
PC0 - - - - - - - - - - - - - - EVENTOUT
STP

PC1 - - - - - - - - - - - ETH_MDC - - - EVENTOUT

OTG_HS_ULPI_
PC2 - - - - - SPI2_MISO - - - - ETH _MII_TXD2 - - - EVENTOUT
DIR
OTG_HS_ULPI_ ETH
PC3 - - - - - SPI2_MOSI - - - - - - - EVENTOUT
NXT _MII_TX_CLK
ETH_MII_RXD0
PC4 - - - - - - - - - - - - - - EVENTOUT
ETH_RMII_RXD0
ETH _MII_RXD1
PC5 - - - - - - - - - - - - - - EVENTOUT
ETH _RMII_RXD1

PC6 - - TIM3_CH1 TIM8_CH1 - I2S2_MCK - - USART6_TX - - - SDIO_D6 DCMI_D0 - EVENTOUT

PC7 - - TIM3_CH2 TIM8_CH2 - - I2S3_MCK - USART6_RX - - - SDIO_D7 DCMI_D1 - EVENTOUT

Port C
PC8 - - TIM3_CH3 TIM8_CH3 - - - - USART6_CK - - - SDIO_D0 DCMI_D2 - EVENTOUT

PC9 MCO2 - TIM3_CH4 TIM8_CH4 I2C3_SDA I2S2_CKIN I2S3_CKIN - - - - - SDIO_D1 DCMI_D3 - EVENTOUT

SPI3_SCK
PC10 - - - - - - USART3_TX UART4_TX - - - SDIO_D2 DCMI_D8 - EVENTOUT
I2S3_SCK
PC11 - - - - - - SPI3_MISO USART3_RX UART4_RX - - - SDIO_D3 DCMI_D4 - EVENTOUT
DocID17050 Rev 13

SPI3_MOSI
PC12 - - - - - - USART3_CK UART5_TX - - - SDIO_CK DCMI_D9 - EVENTOUT
I2S3_SD
PC13 - - - - - - - - - - - - - - - EVENTOUT

PC14-
- - - - - - - - - - - - - - - EVENTOUT
OSC32_IN
PC15-
OSC32_OU - - - - - - - - - - - - - - - EVENTOUT
T

STM32F21xxx
 Table 9. Alternate function mapping (continued)

STM32F21xxx
AF0 AF1 AF2 AF3 AF4 AF5 AF6 AF7 AF8 AF9 AF10 AF11 AF12 AF13
Port AF014 AF15
UART4/5/ CAN1/CAN2/ FSMC/SDIO/
SYS TIM1/2 TIM3/4/5 TIM8/9/10/11 I2C1/I2C2/I2C3 SPI1/SPI2/I2S2 SPI3/I2S3 USART1/2/3 OTG_FS/ OTG_HS ETH DCMI
USART6 TIM12/13/14 OTG_HS

PD0 - - - - - - - - - CAN1_RX - - FSMC_D2 - - EVENTOUT

PD1 - - - - - - - - - CAN1_TX - - FSMC_D3 - - EVENTOUT

PD2 - - TIM3_ETR - - - - - UART5_RX - - - SDIO_CMD DCMI_D11 - EVENTOUT

PD3 - - - - - - - USART2_CTS - - - - FSMC_CLK - - EVENTOUT

PD4 - - - - - - - USART2_RTS - - - - FSMC_NOE - - EVENTOUT

PD5 - - - - - - - USART2_TX - - - - FSMC_NWE - - EVENTOUT

PD6 - - - - - - - USART2_RX - - - - FSMC_NWAIT - - EVENTOUT

FSMC_NE1/
PD7 - - - - - - - USART2_CK - - - - - - EVENTOUT
FSMC_NCE2
Port D
PD8 - - - - - - - USART3_TX - - - - FSMC_D13 - - EVENTOUT

PD9 - - - - - - - USART3_RX - - - - FSMC_D14 - - EVENTOUT

PD10 - - - - - - - USART3_CK - - - - FSMC_D15 - - EVENTOUT

PD11 - - - - - - - USART3_CTS - - - - FSMC_A16 - - EVENTOUT

DocID17050 Rev 13

PD12 - - TIM4_CH1 - - - - USART3_RTS - - - - FSMC_A17 - - EVENTOUT

PD13 - - TIM4_CH2 - - - - - - - - - FSMC_A18 - - EVENTOUT

PD14 - - TIM4_CH3 - - - - - - - - - FSMC_D0 - - EVENTOUT

PD15 - - TIM4_CH4 - - - - - - - - - FSMC_D1 - - EVENTOUT

PE0 - - TIM4_ETR - - - - - - - - - FSMC_NBL0 DCMI_D2 - EVENTOUT

PE1 - - - - - - - - - - - - FSMC_NBL1 DCMI_D3 - EVENTOUT

PE2 TRACECLK - - - - - - - - - - ETH _MII_TXD3 FSMC_A23 - - EVENTOUT

PE3 TRACED0 - - - - - - - - - - - FSMC_A19 - - EVENTOUT

PE4 TRACED1 - - - - - - - - - - - FSMC_A20 DCMI_D4 - EVENTOUT

PE5 TRACED2 - - TIM9_CH1 - - - - - - - - FSMC_A21 DCMI_D6 - EVENTOUT

PE6 TRACED3 - - TIM9_CH2 - - - - - - - - FSMC_A22 DCMI_D7 - EVENTOUT

Pinouts and pin description

PE7 - TIM1_ETR - - - - - - - - - - FSMC_D4 - - EVENTOUT
Port E
PE8 - TIM1_CH1N - - - - - - - - - - FSMC_D5 - - EVENTOUT

PE9 - TIM1_CH1 - - - - - - - - - - FSMC_D6 - - EVENTOUT

PE10 - TIM1_CH2N - - - - - - - - - - FSMC_D7 - - EVENTOUT

PE11 - TIM1_CH2 - - - - - - - - - - FSMC_D8 - - EVENTOUT

PE12 - TIM1_CH3N - - - - - - - - - - FSMC_D9 - - EVENTOUT

PE13 - TIM1_CH3 - - - - - - - - - - FSMC_D10 - - EVENTOUT

PE14 - TIM1_CH4 - - - - - - - - - - FSMC_D11 - - EVENTOUT

63/10

PE15 - TIM1_BKIN - - - - - - - - - - FSMC_D12 - - EVENTOUT

 Table 9. Alternate function mapping (continued)
64/10

Pinouts and pin description

AF0 AF1 AF2 AF3 AF4 AF5 AF6 AF7 AF8 AF9 AF10 AF11 AF12 AF13
Port AF014 AF15
UART4/5/ CAN1/CAN2/ FSMC/SDIO/
SYS TIM1/2 TIM3/4/5 TIM8/9/10/11 I2C1/I2C2/I2C3 SPI1/SPI2/I2S2 SPI3/I2S3 USART1/2/3 OTG_FS/ OTG_HS ETH DCMI
USART6 TIM12/13/14 OTG_HS

PF0 - - - - I2C2_SDA - - - - - - - FSMC_A0 - - EVENTOUT

PF1 - - - - I2C2_SCL - - - - - - FSMC_A1 - - EVENTOUT

PF2 - - - - I2C2_SMBA - - - - - - - FSMC_A2 - - EVENTOUT

PF3 - - - - - - - - - - - - FSMC_A3 - - EVENTOUT

PF4 - - - - - - - - - - - - FSMC_A4 - - EVENTOUT

PF5 - - - - - - - - - - - - FSMC_A5 - - EVENTOUT

PF6 - - - TIM10_CH1 - - - - - - - - FSMC_NIORD - - EVENTOUT

PF7 - - - TIM11_CH1 - - - - - - - - FSMC_NREG - - EVENTOUT

Port F
PF8 - - - - - - - - - TIM13_CH1 - - FSMC_NIOWR - - EVENTOUT

PF9 - - - - - - - - - TIM14_CH1 - - FSMC_CD - - EVENTOUT

PF10 - - - - - - - - - - - - FSMC_INTR - - EVENTOUT

PF11 - - - - - - - - - - - - DCMI_D12 - EVENTOUT

DocID17050 Rev 13

PF12 - - - - - - - - - - - - FSMC_A6 - - EVENTOUT

PF13 - - - - - - - - - - - - FSMC_A7 - - EVENTOUT

PF14 - - - - - - - - - - - - FSMC_A8 - - EVENTOUT

PF15 - - - - - - - - - - - - FSMC_A9 - - EVENTOUT

PG0 - - - - - - - - - - - - FSMC_A10 - - EVENTOUT

PG1 - - - - - - - - - - - - FSMC_A11 - - EVENTOUT

PG2 - - - - - - - - - - - - FSMC_A12 - - EVENTOUT

PG3 - - - - - - - - - - - - FSMC_A13 - - EVENTOUT

PG4 - - - - - - - - - - - - FSMC_A14 - - EVENTOUT

PG5 - - - - - - - - - - - - FSMC_A15 - - EVENTOUT

PG6 - - - - - - - - - - - - FSMC_INT2 - - EVENTOUT

PG7 - - - - - - - - USART6_CK - - - FSMC_INT3 - - EVENTOUT

Port G PG8 - - - - - - - - USART6_RTS - - ETH _PPS_OUT - - - EVENTOUT

FSMC_NE2/
PG9 - - - - - - - - USART6_RX - - - - - EVENTOUT
FSMC_NCE3
FSMC_NCE4_1/
PG10 - - - - - - - - - - - - - - EVENTOUT
FSMC_NE3
ETH _MII_TX_EN
PG11 - - - - - - - - - - - ETH FSMC_NCE4_2 - - EVENTOUT

STM32F21xxx
_RMII_TX_EN

PG12 - - - - - - - - USART6_RTS - - - FSMC_NE4 - - EVENTOUT

ETH _MII_TXD0
PG13 - - - - - - - - UART6_CTS - - FSMC_A24 - - EVENTOUT
ETH _RMII_TXD0
ETH _MII_TXD1
PG14 - - - - - - - - USART6_TX - - FSMC_A25 - - EVENTOUT
ETH _RMII_TXD1

PG15 - - - - - - - - USART6_CTS - - - - DCMI_D13 - EVENTOUT

 Table 9. Alternate function mapping (continued)

STM32F21xxx
AF0 AF1 AF2 AF3 AF4 AF5 AF6 AF7 AF8 AF9 AF10 AF11 AF12 AF13
Port AF014 AF15
UART4/5/ CAN1/CAN2/ FSMC/SDIO/
SYS TIM1/2 TIM3/4/5 TIM8/9/10/11 I2C1/I2C2/I2C3 SPI1/SPI2/I2S2 SPI3/I2S3 USART1/2/3 OTG_FS/ OTG_HS ETH DCMI
USART6 TIM12/13/14 OTG_HS
PH0 -
- - - - - - - - - - - - - - - EVENTOUT
OSC_IN
PH1 -
- - - - - - - - - - - - EVENTOUT
OSC_OUT

PH2 - - - - - - - - ETH _MII_CRS - - - EVENTOUT

PH3 - - - - - - - - ETH _MII_COL - - - EVENTOUT

OTG_HS_ULPI_N
PH4 - - I2C2_SCL - - - - - - - - - EVENTOUT
XT
PH5 - - I2C2_SDA - - - - - - - - - - EVENTOUT

PH6 - - I2C2_SMBA - - - - TIM12_CH1 - ETH _MII_RXD2 - - - EVENTOUT

PH7 - - I2C3_SCL - - - - - - ETH _MII_RXD3 - - - EVENTOUT

Port H
PH8 - - I2C3_SDA - - - - - - - - DCMI_HSYNC - EVENTOUT

PH9 - - I2C3_SMBA - - - - TIM12_CH2 - - - DCMI_D0 - EVENTOUT

PH10 - - TIM5_CH1 - - - - - - - - DCMI_D1 - EVENTOUT

PH11 - - TIM5_CH2 - - - - - - - - DCMI_D2 - EVENTOUT

DocID17050 Rev 13

PH12 - - TIM5_CH3 - - - - - - - - DCMI_D3 - EVENTOUT

PH13 - - TIM8_CH1N - - - - CAN1_TX - - - - - EVENTOUT

PH14 - - TIM8_CH2N - - - - - - - - DCMI_D4 - EVENTOUT

PH15 - - TIM8_CH3N - - - - - - - - DCMI_D11 - EVENTOUT

SPI2_NSS
PI0 - - TIM5_CH4 - - - - - - - DCMI_D13 - EVENTOUT
I2S2_WS
SPI2_SCK
PI1 - - - - - - - - - DCMI_D8 - EVENTOUT
I2S2_SCK
PI2 - - TIM8_CH4 SPI2_MISO - - - - - - - DCMI_D9 - EVENTOUT

SPI2_MOSI
PI3 - - TIM8_ETR - - - - - - - DCMI_D10 - EVENTOUT
I2S2_SD

PI4 - - TIM8_BKIN - - - - - - - - DCMI_D5 - EVENTOUT

PI5 - - TIM8_CH1 - - - - - - - - DCMI_VSYNC - EVENTOUT

Port I
PI6 - - TIM8_CH2 - - - - - - - - DCMI_D6 - EVENTOUT

Pinouts and pin description

PI7 - - TIM8_CH3 - - - - - - - - DCMI_D7 - EVENTOUT

PI8 - - - - - - - - - - - - EVENTOUT

PI9 - - - - - - CAN1_RX - - - - - EVENTOUT

PI10 - - - - - - - - ETH _MII_RX_ER - - - EVENTOUT

OTG_HS_ULPI_
PI11 - - - - - - - - - - - EVENTOUT
DIR
65/10
Memory mapping STM32F21xxx

5 Memory mapping

The memory map is shown in Figure 14.

66/180 DocID17050 Rev 13

STM32F21xxx Memory mapping

Figure 14. Memory map

2ESERVED X! X"&&&&&&&
&3-#CONTROLREGISTER X! X!&&&
&3-#BANK0##ARD X X&&&&&&&
&3-#BANK.!.$.!.$ X X&&&&&&&
&3-#BANK.!.$.!.$ X X&&&&&&&
&3-#BANK./2032!- X# X&&&&&&&
&3-#BANK./2032!- X X"&&&&&&
&3-#BANK./2032!- X X&&&&&&
&3-#BANK./2032!- X X&&&&&&
2ESERVED X# X&&&&&&&
2.' X X&&&
(!3( X X&&
#290 X X&&
2ESERVED X X&&&
$#-) X X&&
2ESERVED X X&&&
53"/4'&3 X X&&&&
2ESERVED X X&&&&&&&
53"/4'(3 X X&&&&
2ESERVED X X&&&&
%4(%2.%4 X X&&
2ESERVED X X&&&
$-! X X&&
$-! X X&&
2ESERVED X X&&&
"+032!- X X&&&
&LASHINTERFACE X# X&&&
2ESETCLOCKCONTROLLER2## X X"&&
2ESERVED X X&&
#2# X X&&
2ESERVED X X&&&
0ORT) X X&&
0ORT( X# X&&&
0ORT' X X"&&
0ORT& X X&&
0ORT% X X&&
0ORT$ X# X&&&
0ORT# X X"&&
0ORT" X X&&
0ORT! X X&&
2ESERVED X# X&&&&
4)- X X"&&
4)- X X&&
4)- X X&&
%84) X# X&&&
393#&' X X"&&
2ESERVED X X&&
30) X X&&
X&&&&&&&&  -BYTE 3$)/ X# X&&&
BLOCK 2ESERVED X X"&&
#ORTEX -gS 2ESERVED X X&&
INTERNAL !$# !$# !$# X X&&
X% PERIPHERALS 2ESERVED X X&&&
X$&&&&&&& 53!24 X X&&
 -BYTE 53!24 X X&&
BLOCK 2ESERVED
.OTUSED 4)-07- X X&&
4)-07- X X&&
X#
X"&&&&&&& 2ESERVED X X&&&&
$!#$!# X X&&
 -BYTE
072 X X&&
BLOCK
2ESERVED X# X&&&
&3-#REGISTERS
"X#!. X X"&&
X! "X#!. X X&&
X&&&&&&&
 -BYTE 2ESERVED X X&&
BLOCK )# X# X&&&
&3-#BANK )# X X"&&
BANK )# X X&&
X 5!24 X X&&
X&&&&&&& 5!24 X# X&&&
 -BYTE
53!24 X X"&&
BLOCK
53!24 X X&&
&3-#BANK
2ESERVED X X&&
BANK
X 30))3 X# X&&&
X&&&&&&& 30))3 X X"&&
 -BYTE 2ESERVED X X&&
BLOCK )7$' X X&&
0ERIPHERALS 77$' X# X&&&
X 24#"+0REGISTERS X X"&&
X&&&&&&& 2ESERVED X X&&
 -BYTE 2ESERVED X X&&&&&&& 4)- X X&&
BLOCK 32!-+"ALIASED X# X&&&&
4)- X# X&&&
32!- BYBIT BANDING 4)- X X"&&
32!-+"ALIASED 4)- X X&&
X X X"&&&
X&&&&&&& BYBIT BANDING 4)- X X&&
4)- X# X&&&
 -BYTE
BLOCK 2ESERVED X&&&# X&&&&&&& 4)- X X"&&
/PTION"YTES X&&&# X&&&# 4)- X X&&
#ODE
2ESERVED X&&&! X&&&&&& 4)- X X&&
X
3YSTEMMEMORY/40 X&&& X&&&!&
2ESERVED X X&&&&&&&
&LASH X X&&&&&
2ESERVED X# X&&&&&&
!LIASEDTO&LASHSYSTEM
MEMORYOR32!-DEPENDING X X&&&&&
ONTHE"//4PINS
AIC

DocID17050 Rev 13 67/180

179
Electrical characteristics STM32F21xxx

6 Electrical characteristics

6.1 Parameter conditions

Unless otherwise specified, all voltages are referenced to VSS.

6.1.1 Minimum and maximum values

Unless otherwise specified the minimum and maximum values are guaranteed in the worst
conditions of ambient temperature, supply voltage and frequencies by tests in production on
100% of the devices with an ambient temperature at TA = 25 °C and TA = TAmax (given by
the selected temperature range).
Data based on characterization results, design simulation and/or technology characteristics
are indicated in the table footnotes and are not tested in production. Based on
characterization, the minimum and maximum values refer to sample tests and represent the
mean value plus or minus three times the standard deviation (mean±3Σ).

6.1.2 Typical values

Unless otherwise specified, typical data are based on TA = 25 °C, VDD = 3.3 V (for the
1.8 V ≤VDD ≤3.6 V voltage range). They are given only as design guidelines and are not
tested.
Typical ADC accuracy values are determined by characterization of a batch of samples from
a standard diffusion lot over the full temperature range, where 95% of the devices have an
error less than or equal to the value indicated (mean±2Σ).

6.1.3 Typical curves

Unless otherwise specified, all typical curves are given only as design guidelines and are
not tested.

6.1.4 Loading capacitor

The loading conditions used for pin parameter measurement are shown in Figure 15.

6.1.5 Pin input voltage

The input voltage measurement on a pin of the device is described in Figure 16.

Figure 15. Pin loading conditions Figure 16. Pin input voltage

-#5PIN -#5PIN

#P& 6).

-36 -36

68/180 DocID17050 Rev 13

STM32F21xxx Electrical characteristics

6.1.6 Power supply scheme

Figure 17. Power supply scheme

9%$7

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287
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069

1. Each power supply pair must be decoupled with filtering ceramic capacitors as shown above. These capacitors must be
placed as close as possible to, or below, the appropriate pins on the underside of the PCB to ensure the good functionality
of the device.
2. To connect REGOFF pin, refer to Section 3.16: Voltage regulator.
3. The two 2.2 µF ceramic capacitors should be replaced by two 100 nF decoupling capacitors when the voltage regulator is
OFF.
4. The 4.7 µF ceramic capacitor must be connected to one of the VDD pin.
Caution: Each power supply pair (VDD/VSS, VDDA/VSSA ...) must be decoupled with filtering ceramic
capacitors as shown above. These capacitors must be placed as close as possible to, or
below, the appropriate pins on the underside of the PCB, to ensure good device operation. It
is not recommended to remove filtering capacitors to reduce PCB size or cost. This might
cause incorrect device operation.

DocID17050 Rev 13 69/180

179
Electrical characteristics STM32F21xxx

6.1.7 Current consumption measurement

Figure 18. Current consumption measurement scheme

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6.2 Absolute maximum ratings

Stresses above the absolute maximum ratings listed in Table 10: Voltage characteristics,
Table 11: Current characteristics, and Table 12: Thermal characteristics may cause
permanent damage to the device. These are stress ratings only and functional operation of
the device at these conditions is not implied. Exposure to maximum rating conditions for
extended periods may affect device reliability.

Table 10. Voltage characteristics

Symbol Ratings Min Max Unit

VDD–VSS External main supply voltage (including VDDA, VDD)(1) –0.3 4.0
Input voltage on five-volt tolerant pin(2) VSS–0.3 VDD+4 V
VIN
Input voltage on any other pin VSS–0.3 4.0
|ΔVDDx| Variations between different VDD power pins - 50
mV
|VSSX − VSS| Variations between all the different ground pins - 50
see Section 6.3.14:
Absolute maximum
VESD(HBM) Electrostatic discharge voltage (human body model) -
ratings (electrical
sensitivity)
1. All main power (VDD, VDDA) and ground (VSS, VSSA) pins must always be connected to the external power
supply, in the permitted range.
2. VIN maximum value must always be respected. Refer to Table 11 for the values of the maximum allowed
injected current.

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STM32F21xxx Electrical characteristics

Table 11. Current characteristics

Symbol Ratings Max Unit

IVDD Total current into VDD power lines (source)(1) 120

(1)
IVSS Total current out of VSS ground lines (sink) 120
Output current sunk by any I/O and control pin 25
IIO
Output current source by any I/Os and control pin 25 mA
(3)
Injected current on five-volt tolerant I/O –5/+0
IINJ(PIN) (2)
(4)
Injected current on any other pin ±5
ΣIINJ(PIN) (4) Total injected current (sum of all I/O and control pins) (5)
±25
1. All main power (VDD, VDDA) and ground (VSS, VSSA) pins must always be connected to the external power
supply, in the permitted range.
2. Negative injection disturbs the analog performance of the device. See note in Section 6.3.20: 12-bit ADC
characteristics.
3. Positive injection is not possible on these I/Os. A negative injection is induced by VIN<VSS. IINJ(PIN) must
never be exceeded. Refer to Table 10 for the values of the maximum allowed input voltage.
4. A positive injection is induced by VIN>VDD while a negative injection is induced by VIN<VSS. IINJ(PIN) must
never be exceeded. Refer to Table 10 for the values of the maximum allowed input voltage.
5. When several inputs are submitted to a current injection, the maximum ΣIINJ(PIN) is the absolute sum of the
positive and negative injected currents (instantaneous values).

Table 12. Thermal characteristics

Symbol Ratings Value Unit

TSTG Storage temperature range –65 to +150 °C

TJ Maximum junction temperature 125 °C

6.3 Operating conditions

6.3.1 General operating conditions

Table 13. General operating conditions

Symbol Parameter Conditions Min Max Unit

fHCLK Internal AHB clock frequency - 0 120

fPCLK1 Internal APB1 clock frequency - 0 30 MHz
fPCLK2 Internal APB2 clock frequency - 0 60

DocID17050 Rev 13 71/180

179
Electrical characteristics STM32F21xxx

Table 13. General operating conditions (continued)

Symbol Parameter Conditions Min Max Unit

VDD Standard operating voltage - 1.8 3.6

Analog operating voltage
1.8 3.6
(ADC limited to 1 M samples)
VDDA(1) Must be the same potential as VDD(2)
Analog operating voltage
2.4 3.6
(ADC limited to 2 M samples)
VBAT Backup operating voltage - 1.65 3.6
2 V ≤ VDD ≤ 3.6 V –0.3 5.5 V
Input voltage on RST and FT pins
1.7 V ≤ VDD ≤ 2 V –0.3 5.2
VIN
Input voltage on TTa pins - –0.3 VDD+0.3
Input voltage on BOOT0 pin - 0 9
VCAP1 Internal core voltage to be supplied
- 1.1 1.3
VCAP2 externally in REGOFF mode

LQFP64 - 444
LQFP100 - 434
Power dissipation at TA = 85 °C for
PD LQFP144 - 500 mW
suffix 6 or TA = 105 °C for suffix 7(3)
LQFP176 - 526
UFBGA176 - 513

Ambient temperature for 6 suffix Maximum power dissipation –40 85

°C
version Low-power dissipation (4)
–40 105
TA
Ambient temperature for 7 suffix Maximum power dissipation –40 105
°C
version Low-power dissipation (4)
–40 125
6 suffix version –40 105
TJ Junction temperature range °C
7 suffix version –40 125
1. When the ADC is used, refer to Table 65: ADC characteristics.
2. It is recommended to power VDD and VDDA from the same source. A maximum difference of 300 mV between VDD and
VDDA can be tolerated during power-up and power-down operation.
3. If TA is lower, higher PD values are allowed as long as TJ does not exceed TJmax.
4. In low-power dissipation state, TA can be extended to this range as long as TJ does not exceed TJmax.

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Table 14. Limitations depending on the operating power supply range

Maximum Number of wait
Operating Flash states at FSMC_CLK Possible
power ADC memory maximum CPU frequency for Flash
I/O operation
supply operation access frequency synchronous memory
range frequency (fCPUmax= accesses operations
(fFlashmax) 120 MHz)(1)

– Degraded
16 MHz with speed 8-bit erase
Conversion
VDD =1.8 to no Flash (2) performance Up to 30 MHz and program
time up to 7
2.1 V memory wait operations
1 Msps – No I/O
state only
compensation
– Degraded
18 MHz with speed
Conversion 16-bit erase
VDD = 2.1 to no Flash
time up to 6(2) performance Up to 30 MHz and program
2.4 V memory wait
1 Msps – No I/O operations
state
compensation
– Degraded
24 MHz with speed
Conversion performance 16-bit erase
VDD = 2.4 to no Flash
time up to 4(2) Up to 48 MHz and program
2.7 V memory wait – I/O
2 Msps operations
state compensation
works
– Up to
60 MHz
– Full-speed
30 MHz with when VDD =
Conversion operation 32-bit erase
VDD = 2.7 to no Flash 3.0 to 3.6 V
time up to 3(2) – I/O and program
3.6 V(3) memory wait – Up to
2 Msps compensation operations
state 48 MHz
works
when VDD =
2.7 to 3.0 V
1. The number of wait states can be reduced by reducing the CPU frequency (see Figure 19).
2. Thanks to the ART accelerator and the 128-bit Flash memory, the number of wait states given here does not impact the
execution speed from Flash memory since the ART accelerator allows to achieve a performance equivalent to 0 wait state
program execution.
3. The voltage range for OTG USB FS can drop down to 2.7 V. However it is degraded between 2.7 and 3 V.

DocID17050 Rev 13 73/180

179
Electrical characteristics STM32F21xxx

Figure 19. Number of wait states versus fCPU and VDD range

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6.3.2 VCAP1/VCAP2 external capacitor

Stabilization for the main regulator is achieved by connecting an external capacitor to the
VCAP1/VCAP2 pins. CEXT is specified in Table 15.

Figure 20. External capacitor CEXT

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069

1. Legend: ESR is the equivalent series resistance.

Table 15. VCAP1/VCAP2 operating conditions(1)

Symbol Parameter Conditions

CEXT Capacitance of external capacitor 2.2 µF

ESR ESR of external capacitor <2Ω
1. When bypassing the voltage regulator, the two 2.2 µF VCAP capacitors are not required and should be
replaced by two 100 nF decoupling capacitors.

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6.3.3 Operating conditions at power-up / power-down (regulator ON)

Subject to general operating conditions for TA.

Table 16. Operating conditions at power-up / power-down (regulator ON)

Symbol Parameter Min Max Unit

VDD rise time rate 20 ∞

tVDD µs/V
VDD fall time rate 20 ∞

6.3.4 Operating conditions at power-up / power-down (regulator OFF)

Subject to general operating conditions for TA.

Table 17. Operating conditions at power-up / power-down (regulator OFF)

Symbol Parameter Conditions Min Max Unit

VDD rise time rate Power-up 20 ∞

tVDD
VDD fall time rate Power-down 20 ∞
VCAP_1 and VCAP_2 rise µs/V
time rate
Power-up 20 ∞
tVCAP
VCAP_1 and VCAP_2 fall
time rate
Power-down 20 ∞

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Electrical characteristics STM32F21xxx

6.3.5 Embedded reset and power control block characteristics

The parameters given in Table 18 are derived from tests performed under ambient
temperature and VDD supply voltage conditions summarized in Table 13.

Table 18. Embedded reset and power control block characteristics

Symbol Parameter Conditions Min Typ Max Unit

PLS[2:0]=000 (rising
2.09 2.14 2.19 V
edge)
PLS[2:0]=000 (falling
1.98 2.04 2.08 V
edge)
PLS[2:0]=001 (rising
2.23 2.30 2.37 V
edge)
PLS[2:0]=001 (falling
2.13 2.19 2.25 V
edge)
PLS[2:0]=010 (rising
2.39 2.45 2.51 V
edge)
PLS[2:0]=010 (falling
2.29 2.35 2.39 V
edge)
PLS[2:0]=011 (rising edge) 2.54 2.60 2.65 V
PLS[2:0]=011 (falling
Programmable voltage edge) 2.44 2.51 2.56 V
VPVD
detector level selection
PLS[2:0]=100 (rising
2.70 2.76 2.82 V
edge)
PLS[2:0]=100 (falling
2.59 2.66 2.71 V
edge)
PLS[2:0]=101 (rising
2.86 2.93 2.99 V
edge)
PLS[2:0]=101 (falling
2.65 2.84 3.02 V
edge)
PLS[2:0]=110 (rising edge) 2.96 3.03 3.10 V
PLS[2:0]=110 (falling
2.85 2.93 2.99 V
edge)
PLS[2:0]=111 (rising edge) 3.07 3.14 3.21 V
PLS[2:0]=111 (falling
2.95 3.03 3.09 V
edge)
VPVDhyst(1) PVD hysteresis - - 100 - mV

Power-on/power-down Falling edge 1.60 1.68 1.76 V

VPOR/PDR
reset threshold Rising edge 1.64 1.72 1.80 V
(1)
VPDRhyst PDR hysteresis - - 40 - mV

Brownout level 1 Falling edge 2.13 2.19 2.24 V

VBOR1
threshold Rising edge 2.23 2.29 2.33 V

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Table 18. Embedded reset and power control block characteristics (continued)
Symbol Parameter Conditions Min Typ Max Unit

Brownout level 2 Falling edge 2.44 2.50 2.56 V

VBOR2
threshold Rising edge 2.53 2.59 2.63 V

Brownout level 3 Falling edge 2.75 2.83 2.88 V

VBOR3
threshold Rising edge 2.85 2.92 2.97 V
VBORhyst(1) BOR hysteresis - - 100 - mV
TRSTTEMPO(1)(2) Reset temporization - 0.5 1.5 3.0 ms
InRush current on
voltage regulator
IRUSH(1) - - 160 200 mA
power-on (POR or
wakeup from Standby)
InRush energy on
voltage regulator VDD = 1.8 V, TA = 105 °C,
ERUSH(1) - - 5.4 µC
power-on (POR or IRUSH = 171 mA for 31 µs
wakeup from Standby)
1. Guaranteed by design, not tested in production.
2. The reset temporization is measured from the power-on (POR reset or wakeup from VBAT) to the instant
when first instruction is read by the user application code.

6.3.6 Supply current characteristics

The current consumption is a function of several parameters and factors such as the
operating voltage, ambient temperature, I/O pin loading, device software configuration,
operating frequencies, I/O pin switching rate, program location in memory and executed
binary code.
The current consumption is measured as described in Figure 18: Current consumption
measurement scheme.
All Run mode current consumption measurements given in this section are performed using
CoreMark® code.

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Electrical characteristics STM32F21xxx

Typical and maximum current consumption

The MCU is placed under the following conditions:
• At startup, all I/O pins are configured as analog inputs by firmware.
• All peripherals are disabled except if it is explicitly mentioned.
• The Flash memory access time is adjusted to fHCLK frequency (0 wait state from 0 to
30 MHz, 1 wait state from 30 to 60 MHz, 2 wait states from 60 to 90 MHz and 3 wait
states from 90 to 120 MHz).
• When the peripherals are enabled HCLK is the system clock, fPCLK1 = fHCLK/4, and
fPCLK2 = fHCLK/2, except is explicitly mentioned.
• The maximum values are obtained for VDD = 3.6 V and maximum ambient temperature
(TA), and the typical values for TA= 25 °C and VDD = 3.3 V unless otherwise specified.

Table 19. Typical and maximum current consumption in Run mode, code with data processing
running from Flash memory (ART accelerator enabled) or RAM (1)
Typ Max(2)
Symbol Parameter Conditions fHCLK Unit
TA = 25 °C TA = 85 °C TA = 105 °C

120 MHz 49 63 72
90 MHz 38 51 61
60 MHz 26 39 49
30 MHz 14 27 37
External clock(3), all
25 MHz 11 24 34
peripherals enabled(4)
16 MHz(5) 8 21 30
8 MHz 5 17 27
4 MHz 3 16 26

Supply current 2 MHz 2 15 25

IDD mA
in Run mode 120 MHz 21 34 44
90 MHz 17 30 40
60 MHz 12 25 35
30 MHz 7 20 30
External clock(3), all
25 MHz 5 18 28
peripherals disabled
16 MHz(5) 4.0 17.0 27.0
8 MHz 2.5 15.5 25.5
4 MHz 2.0 14.7 24.8
2 MHz 1.6 14.5 24.6
1. Code and data processing running from SRAM1 using boot pins.
2. Guaranteed by characterization, tested in production at VDD max and fHCLK max with peripherals enabled.
3. External clock is 4 MHz and PLL is on when fHCLK > 25 MHz.
4. When the ADC is on (ADON bit set in the ADC_CR2 register), add an additional power consumption of 1.6 mA per ADC for
the analog part.
5. In this case HCLK = system clock/2.

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Table 20. Typical and maximum current consumption in Run mode, code with data processing
running from Flash memory (ART accelerator disabled)
Typ Max(1)
Symbol Parameter Conditions fHCLK Unit
TA = 25 °C TA = 85 °C TA = 105 °C

120 MHz 61 81 93
90 MHz 48 68 80
60 MHz 33 53 65
30 MHz 18 38 50
External clock(2), all
25 MHz 14 34 46
peripherals enabled(3)
16 MHz(4) 10 30 42
8 MHz 6 26 38
4 MHz 4 24 36

Supply current 2 MHz 3 23 35

IDD mA
in Run mode 120 MHz 33 54 66
90 MHz 27 47 59
60 MHz 19 39 51
30 MHz 11 31 43
External clock(2), all
25 MHz 8 28 41
peripherals disabled
16 MHz(4) 6 26 38
8 MHz 4 24 36
4 MHz 3 23 35
2 MHz 2 23 34
1. Guaranteed by characterization results, tested in production at VDD max and fHCLK max with peripherals enabled.
2. External clock is 4 MHz and PLL is on when fHCLK > 25 MHz.
3. When the ADC is on (ADON bit set in the ADC_CR2 register), add an additional power consumption of 1.6 mA per ADC for
the analog part.
4. In this case HCLK = system clock/2.

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Electrical characteristics STM32F21xxx

Figure 21. Typical current consumption vs. temperature, Run mode, code with data
processing running from RAM, and peripherals ON





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Figure 22. Typical current consumption vs. temperature, Run mode, code with data
processing running from RAM, and peripherals OFF





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80/180 DocID17050 Rev 13

STM32F21xxx Electrical characteristics

Figure 23. Typical current consumption vs. temperature, Run mode, code with data
processing running from Flash, ART accelerator OFF, peripherals ON






)$$25. M!

 

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Figure 24. Typical current consumption vs. temperature, Run mode, code with data
processing running from Flash, ART accelerator OFF, peripherals OFF






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Table 21. Typical and maximum current consumption in Sleep mode

Typ Max(1)
Symbol Parameter Conditions fHCLK Unit
TA = TA = TA =
25 °C 85 °C 105 °C

120 MHz 38 51 61
90 MHz 30 43 53
60 MHz 20 33 43
30 MHz 11 25 35
External clock(2),
25 MHz 8 21 31
all peripherals enabled(3)
16 MHz 6 19 29
8 MHz 3.6 17.0 27.0
4 MHz 2.4 15.4 25.3

Supply current in 2 MHz 1.9 14.9 24.7

IDD mA
Sleep mode 120 MHz 8 21 31
90 MHz 7 20 30
60 MHz 5 18 28
30 MHz 3.5 16.0 26.0
External clock(2), all
25 MHz 2.5 16.0 25.0
peripherals disabled
16 MHz 2.1 15.1 25.0
8 MHz 1.7 15.0 25.0
4 MHz 1.5 14.6 24.6
2 MHz 1.4 14.2 24.3
1. Guaranteed by characterization results, tested in production at VDD max and fHCLK max with peripherals enabled.
2. External clock is 4 MHz and PLL is on when fHCLK > 25 MHz.
3. Add an additional power consumption of 1.6 mA per ADC for the analog part. In applications, this consumption occurs only
while the ADC is on (ADON bit is set in the ADC_CR2 register).

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Figure 25. Typical current consumption vs. temperature in Sleep mode,

peripherals ON







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Figure 26. Typical current consumption vs. temperature in Sleep mode,

peripherals OFF






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Table 22. Typical and maximum current consumptions in Stop mode

Typ Max
Symbol Parameter Conditions Unit
TA = TA = TA = TA =
25 °C 25 °C 85 °C 105 °C

Flash in Stop mode, low-speed and high-speed

Supply current internal RC oscillators and high-speed oscillator 0.55 1.2 11.00 20.00
in Stop mode OFF (no independent watchdog)
with main Flash in Deep power down mode, low-speed
regulator in and high-speed internal RC oscillators and
Run mode 0.50 1.2 11.00 20.00
high-speed oscillator OFF (no independent
watchdog)
IDD_STOP mA
Flash in Stop mode, low-speed and high-speed
Supply current internal RC oscillators and high-speed oscillator 0.35 1.1 8.00 15.00
in Stop mode OFF (no independent watchdog)
with main
regulator in Flash in Deep power down mode, low-speed
Low-power and high-speed internal RC oscillators and
0.30 1.1 8.00 15.00
mode high-speed oscillator OFF (no independent
watchdog)

Figure 27. Typical current consumption vs. temperature in Stop mode


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4EMPERATURE #

-36

1. All typical and maximum values from table 18 and figure 26 will be reduced over time by up to 50% as part
of ST continuous improvement of test procedures. New versions of the datasheet will be released to reflect
these changes

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Table 23. Typical and maximum current consumptions in Standby mode

Typ Max(1)

TA = 25 °C TA = 85 °C TA = 105 °C
Symbol Parameter Conditions Unit
VDD = VDD= VDD =
VDD = 3.6 V
1.8 V 2.4 V 3.3 V

Backup SRAM ON, low-speed

3.0 3.4 4.0 15.1 25.8
oscillator and RTC ON
Supply current Backup SRAM OFF, low-
IDD_STBY in Standby 2.4 2.7 3.3 12.4 20.5 µA
speed oscillator and RTC ON
mode
Backup SRAM ON, RTC OFF 2.4 2.6 3.0 12.5 24.8
Backup SRAM OFF, RTC OFF 1.7 1.9 2.2 9.8 19.2
1. Guaranteed by characterization results, not tested in production.

Table 24. Typical and maximum current consumptions in VBAT mode

Typ Max(1)

TA = 25 °C TA = 85 °C TA = 105 °C
Symbol Parameter Conditions Unit
VDD = VDD= VDD =
VDD = 3.6 V
1.8 V 2.4 V 3.3 V

Backup SRAM ON, low-speed

1.29 1.42 1.68 12 19
oscillator and RTC ON
Backup Backup SRAM OFF, low-speed
IDD_VBAT domain supply oscillator and RTC ON 0.62 0.73 0.96 8 10 µA
current
Backup SRAM ON, RTC OFF 0.79 0.81 0.86 9 16
Backup SRAM OFF, RTC OFF 0.10 0.10 0.10 5 7
1. Guaranteed by characterization results, not tested in production.

On-chip peripheral current consumption

The current consumption of the on-chip peripherals is given in Table 25. The MCU is placed
under the following conditions:
• At startup, all I/O pins are configured as analog inputs by firmware.
• All peripherals are disabled unless otherwise mentioned
• The given value is calculated by measuring the current consumption
– with all peripherals clocked off
– with one peripheral clocked on (with only the clock applied)
• The code is running from Flash memory and the Flash memory access time is equal to
3 wait states at 120 MHz
• Prefetch and Cache ON
• When the peripherals are enabled, HCLK = 120MHz, fPCLK1 = fHCLK/4, and
fPCLK2 = fHCLK/2
• The typical values are obtained for VDD = 3.3 V and TA= 25 °C, unless otherwise
specified.

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Table 25. Peripheral current consumption

Peripheral(1) Typical consumption at 25 °C Unit

GPIO A 0.45
GPIO B 0.43
GPIO C 0.46
GPIO D 0.44
GPIO E 0.44
GPIO F 0.42
GPIO G 0.44
GPIO H 0.42

AHB1 GPIO I 0.43

OTG_HS + ULPI 3.64
mA
CRC 1.17
BKPSRAM 0.21
DMA1 2.76
DMA2 2.85
ETH_MAC +
ETH_MAC_TX
2.99
ETH_MAC_RX
ETH_MAC_PTP
OTG_FS 3.16
AHB2
DCMI 0.60
AHB3 FSMC 1.74
CRYPTO 0.39
AHB2 HASH 0.50 mA
RNG 0.43

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Table 25. Peripheral current consumption (continued)

Peripheral(1) Typical consumption at 25 °C Unit

TIM2 0.61
TIM3 0.49
TIM4 0.54
TIM5 0.62
TIM6 0.20
TIM7 0.20
TIM12 0.36
TIM13 0.28
TIM14 0.25
USART2 0.25
USART3 0.25
UART4 0.25
APB1 mA
UART5 0.26
I2C1 0.25
I2C2 0.25
I2C3 0.25
SPI2 0.20/0.10
SPI3 0.18/0.09
CAN1 0.31
CAN2 0.30
(2)
DAC channel 1 1.11
DAC channel 1(3) 1.11
PWR 0.15
WWDG 0.15

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Table 25. Peripheral current consumption (continued)

Peripheral(1) Typical consumption at 25 °C Unit

SDIO 0.69
TIM1 1.06
TIM8 1.03
TIM9 0.58
TIM10 0.37
TIM11 0.39
APB2 mA
(4)
ADC1 2.13
ADC2(4) 2.04
(4)
ADC3 2.12
SPI1 1.20
USART1 0.38
USART6 0.37
1. External clock is 25 MHz (HSE oscillator with 25 MHz crystal) and PLL is on.
2. EN1 bit is set in DAC_CR register.
3. EN2 bit is set in DAC_CR register.
4. fADC = fPCLK2/2, ADON bit set in ADC_CR2 register.

6.3.7 Wakeup time from low-power mode

The wakeup times given in Table 26 is measured on a wakeup phase with a 16 MHz HSI
RC oscillator. The clock source used to wake up the device depends from the current
operating mode:
• Stop or Standby mode: the clock source is the RC oscillator
• Sleep mode: the clock source is the clock that was set before entering Sleep mode.
All timings are derived from tests performed under ambient temperature and VDD supply
voltage conditions summarized in Table 13.

Table 26. Low-power mode wakeup timings

Symbol Parameter Min(1) Typ(1) Max(1) Unit

tWUSLEEP(2) Wakeup from Sleep mode - 1 - µs

Wakeup from Stop mode (regulator in Run mode) - 13 -

Wakeup from Stop mode (regulator in low-power mode) - 17 40
tWUSTOP(2) µs
Wakeup from Stop mode (regulator in low-power mode
- 110 -
and Flash memory in Deep power down mode)

tWUSTDBY(2)(3) Wakeup from Standby mode 260 375 480 µs

1. Guaranteed by characterization results, not tested in production.

2. The wakeup times are measured from the wakeup event to the point in which the application code reads the first instruction.
3. tWUSTDBY minimum and maximum values are given at 105 °C and –45 °C, respectively.

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6.3.8 External clock source characteristics

High-speed external user clock generated from an external source
The characteristics given in Table 27 result from tests performed using an high-speed
external clock source, and under ambient temperature and supply voltage conditions
summarized in Table 13.

Table 27. High-speed external user clock characteristics

Symbol Parameter Conditions Min Typ Max Unit

External user clock source

fHSE_ext 1 - 26 MHz
frequency(1)
VHSEH OSC_IN input pin high level voltage 0.7VDD - VDD
V
VHSEL OSC_IN input pin low level voltage VSS - 0.3VDD
-
tw(HSE)
OSC_IN high or low time(1) 5 - -
tw(HSE)
ns
tr(HSE)
OSC_IN rise or fall time(1) - - 20
tf(HSE)
Cin(HSE) OSC_IN input capacitance(1) - - 5 - pF
DuCy(HSE) Duty cycle - 45 - 55 %
IL OSC_IN Input leakage current VSS ≤VIN ≤VDD - - ±1 µA
1. Guaranteed by design, not tested in production.

Low-speed external user clock generated from an external source

The characteristics given in Table 28 result from tests performed using an low-speed
external clock source, and under ambient temperature and supply voltage conditions
summarized in Table 13.

Table 28. Low-speed external user clock characteristics

Symbol Parameter Conditions Min Typ Max Unit

fLSE_ext User External clock source frequency(1) - 32.768 1000 kHz

VLSEH OSC32_IN input pin high level voltage 0.7VDD - VDD
V
VLSEL OSC32_IN input pin low level voltage VSS - 0.3VDD
-
tw(LSE)
OSC32_IN high or low time(1) 450 - -
tf(LSE)
ns
tr(LSE)
OSC32_IN rise or fall time(1) - - 50
tf(LSE)
Cin(LSE) OSC32_IN input capacitance(1) - - 5 - pF
DuCy(LSE) Duty cycle - 30 - 70 %
IL OSC32_IN Input leakage current VSS ≤VIN ≤VDD - - ±1 µA
1. Guaranteed by design, not tested in production.

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Electrical characteristics STM32F21xxx

Figure 28. High-speed external clock source AC timing diagram

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Figure 29. Low-speed external clock source AC timing diagram

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High-speed external clock generated from a crystal/ceramic resonator

The high-speed external (HSE) clock can be supplied with a 4 to 26 MHz crystal/ceramic
resonator oscillator. All the information given in this paragraph are based on
characterization results obtained with typical external components specified in Table 29. In
the application, the resonator and the load capacitors have to be placed as close as
possible to the oscillator pins in order to minimize output distortion and startup stabilization
time. Refer to the crystal resonator manufacturer for more details on the resonator
characteristics (frequency, package, accuracy).

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Table 29. HSE 4-26 MHz oscillator characteristics(1) (2)

Symbol Parameter Conditions Min Typ Max Unit

fOSC_IN Oscillator frequency - 4 - 26 MHz

RF Feedback resistor - - 200 - kΩ
VDD=3.3 V,
ESR= 30 Ω, - 449 -
CL=5 pF@25 MHz
IDD HSE current consumption µA
VDD=3.3 V,
ESR= 30 Ω, - 532 -
CL=10 pF@25 MHz
gm Oscillator transconductance Startup 5 - - mA/V
tSU(HSE(3) Startup time VDD is stabilized - 2 - ms
1. Resonator characteristics given by the crystal/ceramic resonator manufacturer.
2. Guaranteed by characterization results, not tested in production.
3. tSU(HSE) is the startup time measured from the moment it is enabled (by software) to a stabilized 8 MHz
oscillation is reached. This value is measured for a standard crystal resonator and it can vary significantly
with the crystal manufacturer

For CL1 and CL2, it is recommended to use high-quality external ceramic capacitors in the
5 pF to 25 pF range (typ.), designed for high-frequency applications, and selected to match
the requirements of the crystal or resonator (see Figure 30). CL1 and CL2 are usually the
same size. The crystal manufacturer typically specifies a load capacitance which is the
series combination of CL1 and CL2. PCB and MCU pin capacitance must be included (10 pF
can be used as a rough estimate of the combined pin and board capacitance) when sizing
CL1 and CL2.
Note: For information on electing the crystal, refer to the application note AN2867 “Oscillator
design guide for ST microcontrollers” available from the ST website www.st.com.

Figure 30. Typical application with an 8 MHz crystal

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1. REXT value depends on the crystal characteristics.

Low-speed external clock generated from a crystal/ceramic resonator

The low-speed external (LSE) clock can be supplied with a 32.768 kHz crystal/ceramic
resonator oscillator. All the information given in this paragraph are based on
characterization results obtained with typical external components specified in Table 30. In
the application, the resonator and the load capacitors have to be placed as close as
possible to the oscillator pins in order to minimize output distortion and startup stabilization
time. Refer to the crystal resonator manufacturer for more details on the resonator
characteristics (frequency, package, accuracy).

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Electrical characteristics STM32F21xxx

Table 30. LSE oscillator characteristics (fLSE = 32.768 kHz) (1)

Symbol Parameter Conditions Min Typ Max Unit

RF Feedback resistor - - 18.4 - MΩ

IDD LSE current consumption - - - 1 µA
gm Oscillator Transconductance - 2.8 - - µA/V
tSU(LSE)(2) startup time VDD is stabilized - 2 - s
1. Guaranteed by design, not tested in production.
2. tSU(LSE) is the startup time measured from the moment it is enabled (by software) to a stabilized
32.768 kHz oscillation is reached. This value is measured for a standard crystal resonator and it can vary
significantly with the crystal manufacturer

Note: For information on electing the crystal, refer to the application note AN2867 “Oscillator
design guide for ST microcontrollers” available from the ST website www.st.com.

Figure 31. Typical application with a 32.768 kHz crystal

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6.3.9 Internal clock source characteristics

The parameters given in Table 31 and Table 32 are derived from tests performed under
ambient temperature and VDD supply voltage conditions summarized in Table 13.

High-speed internal (HSI) RC oscillator

Table 31. HSI oscillator characteristics (1)

Symbol Parameter Conditions Min Typ Max Unit

fHSI Frequency - - 16 - MHz

HSI user-trimming step(2) - - - 1 %
TA = –40 to 105 °C(3) –8 - 4.5 %
ACCHSI Accuracy of the
TA = –10 to 85 °C(3) –4 - 4 %
HSI oscillator
TA = 25 °C(4) –1 - 1 %
(2)
tsu(HSI) HSI oscillator startup time - - 2.2 4.0 µs
IDD(HSI) (2) HSI oscillator power consumption - - 60 80 µA
1. VDD = 3.3 V, TA = –40 to 105 °C unless otherwise specified.
2. Guaranteed by design, not tested in production.
3. Guaranteed by characterization results.
4. Factory calibrated, parts not soldered.

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Figure 32. ACCHSI versus temperature

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Low-speed internal (LSI) RC oscillator

Table 32. LSI oscillator characteristics (1)

Symbol Parameter Min Typ Max Unit

fLSI(2) Frequency 17 32 47 kHz

(3)
tsu(LSI) LSI oscillator startup time - 15 40 µs
IDD(LSI)(3) LSI oscillator power consumption - 0.4 0.6 µA
1. VDD = 3 V, TA = –40 to 105 °C unless otherwise specified.
2. Guaranteed by characterization results, not tested in production.
3. Guaranteed by design, not tested in production.

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Electrical characteristics STM32F21xxx

Figure 33. ACCLSI versus temperature


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4EMPERAT URE #

-36

6.3.10 PLL characteristics

The parameters given in Table 33 and Table 34 are derived from tests performed under
temperature and VDD supply voltage conditions summarized in Table 13.

Table 33. Main PLL characteristics

Symbol Parameter Conditions Min Typ Max Unit

fPLL_IN PLL input clock(1) - 0.95(2) 1 2.10(2) MHz

fPLL_OUT PLL multiplier output clock - 24 - 120 MHz
48 MHz PLL multiplier output
fPLL48_OUT - - - 48 MHz
clock
fVCO_OUT PLL VCO output - 192 - 432 MHz
VCO freq = 192 MHz 75 - 200
tLOCK PLL lock time µs
VCO freq = 432 MHz 100 - 300

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Table 33. Main PLL characteristics (continued)

Symbol Parameter Conditions Min Typ Max Unit

RMS - 25 -

Cycle-to-cycle jitter peak

to - ±150 -
System clock peak
120 MHz RMS - 15 -

Period Jitter peak

(3) to - ±200 -
Jitter ps
peak
Main clock output (MCO) for Cycle to cycle at 50 MHz
- 32 -
RMII Ethernet on 1000 samples
Main clock output (MCO) for MII Cycle to cycle at 25 MHz
- 40 -
Ethernet on 1000 samples
Cycle to cycle at 1 MHz
Bit Time CAN jitter - 330 -
on 1000 samples
VCO freq = 192 MHz 0.15 0.40
IDD(PLL)(4) PLL power consumption on VDD - mA
VCO freq = 432 MHz 0.45 0.75
PLL power consumption on VCO freq = 192 MHz 0.30 0.40
IDDA(PLL)(4) - mA
VDDA VCO freq = 432 MHz 0.55 0.85
1. Take care of using the appropriate division factor M to obtain the specified PLL input clock values. The M factor is shared
between PLL and PLLI2S.
2. Guaranteed by design, not tested in production.
3. The use of 2 PLLs in parallel could degraded the Jitter up to +30%.
4. Guaranteed by characterization results, not tested in production.

Table 34. PLLI2S (audio PLL) characteristics

Symbol Parameter Conditions Min Typ Max Unit

fPLLI2S_IN PLLI2S input clock(1) - 0.95(2) 1 2.10(2) MHz

fPLLI2S_OUT PLLI2S multiplier output clock - - - 216 MHz
fVCO_OUT PLLI2S VCO output - 192 - 432 MHz
VCO freq = 192 MHz 75 - 200
tLOCK PLLI2S lock time µs
VCO freq = 432 MHz 100 - 300

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Electrical characteristics STM32F21xxx

Table 34. PLLI2S (audio PLL) characteristics (continued)

Symbol Parameter Conditions Min Typ Max Unit

Cycle to cycle at RMS - 90 -

12.288 MHz on peak ps
48KHz period, to - ±280 -
N=432, R=5 peak
Master I2S clock jitter
(3) Average frequency of
Jitter
12.288 MHz
- 90 - ps
N=432, R=5
on 1000 samples
Cycle to cycle at 48 KHz
WS I2S clock jitter - 400 - ps
on 1000 samples
PLLI2S power consumption on VCO freq = 192 MHz 0.15 0.40
IDD(PLLI2S)(4) - mA
VDD VCO freq = 432 MHz 0.45 0.75
PLLI2S power consumption on VCO freq = 192 MHz 0.30 0.40
IDDA(PLLI2S)(4) - mA
VDDA VCO freq = 432 MHz 0.55 0.85
1. Take care of using the appropriate division factor M to have the specified PLL input clock values.
2. Guaranteed by design, not tested in production.
3. Value given with main PLL running.
4. Guaranteed by characterization results, not tested in production.

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6.3.11 PLL spread spectrum clock generation (SSCG) characteristics

The spread spectrum clock generation (SSCG) feature allows to reduce electromagnetic
interferences (see Table 41: EMI characteristics). It is available only on the main PLL.

Table 35. SSCG parameters constraint

Symbol Parameter Min Typ Max(1) Unit

fMod Modulation frequency - - 10 KHz

md Peak modulation depth 0.25 - 2 %
MODEPER * INCSTEP - - - 215 −1 -
1. Guaranteed by design, not tested in production.

Equation 1
The frequency modulation period (MODEPER) is given by the equation below:
MODEPER = round [ f PLL_IN ⁄ ( 4 × f Mod ) ]

fPLL_IN and fMod must be expressed in Hz.

As an example:
If fPLL_IN = 1 MHz and fMOD = 1 kHz, the modulation depth (MODEPER) is given by equation
1:
6 3
MODEPER = round [ 10 ⁄ ( 4 × 10 ) ] = 250

Equation 2
Equation 2 allows to calculate the increment step (INCSTEP):
15
INCSTEP = round [ ( ( 2 – 1 ) × md × PLLN ) ⁄ ( 100 × 5 × MODEPER ) ]

fVCO_OUT must be expressed in MHz.

With a modulation depth (md) = ±2 % (4 % peak to peak), and PLLN = 240 (in MHz):
15
INCSTEP = round [ ( ( 2 – 1 ) × 2 × 240 ) ⁄ ( 100 × 5 × 250 ) ] = 126md(quantitazed)%

An amplitude quantization error may be generated because the linear modulation profile is
obtained by taking the quantized values (rounded to the nearest integer) of MODPER and
INCSTEP. As a result, the achieved modulation depth is quantized. The percentage
quantized modulation depth is given by the following formula:
15
md quantized % = ( MODEPER × INCSTEP × 100 × 5 ) ⁄ ( ( 2 – 1 ) × PLLN )

As a result:
15
md quantized % = ( 250 × 126 × 100 × 5 ) ⁄ ( ( 2 – 1 ) × 240 ) = 2.0002%(peak)

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Electrical characteristics STM32F21xxx

Figure 34 and Figure 35 show the main PLL output clock waveforms in center spread and
down spread modes, where:
F0 is fPLL_OUT nominal.
Tmode is the modulation period.
md is the modulation depth.

Figure 34. PLL output clock waveforms in center spread mode

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Figure 35. PLL output clock waveforms in down spread mode

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6.3.12 Memory characteristics

Flash memory
The characteristics are given at TA = –40 to 105 °C unless otherwise specified.

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Table 36. Flash memory characteristics

Symbol Parameter Conditions Min Typ Max Unit

Write / Erase 8-bit mode

- 5 -
VDD = 1.8 V
Write / Erase 16-bit mode
IDD Supply current - 8 - mA
VDD = 2.1 V
Write / Erase 32-bit mode
- 12 -
VDD = 3.3 V

Table 37. Flash memory programming

Symbol Parameter Conditions Min(1) Typ Max(1) Unit

Program/erase parallelism
tprog Word programming time - 16 100(2) µs
(PSIZE) = x 8/16/32
Program/erase parallelism
- 400 800
(PSIZE) = x 8
Program/erase parallelism
tERASE16KB Sector (16 KB) erase time - 300 600 ms
(PSIZE) = x 16
Program/erase parallelism
- 250 500
(PSIZE) = x 32
Program/erase parallelism
- 1200 2400
(PSIZE) = x 8
Program/erase parallelism
tERASE64KB Sector (64 KB) erase time - 700 1400 ms
(PSIZE) = x 16
Program/erase parallelism
- 550 1100
(PSIZE) = x 32
Program/erase parallelism
- 2 4
(PSIZE) = x 8
Program/erase parallelism
tERASE128KB Sector (128 KB) erase time - 1.3 2.6 s
(PSIZE) = x 16
Program/erase parallelism
- 1 2
(PSIZE) = x 32
Program/erase parallelism
- 16 32
(PSIZE) = x 8
Program/erase parallelism
tME Mass erase time - 11 22 s
(PSIZE) = x 16
Program/erase parallelism
- 8 16
(PSIZE) = x 32
32-bit program operation 2.7 - 3.6 V
Vprog Programming voltage 16-bit program operation 2.1 - 3.6 V
8-bit program operation 1.8 - 3.6 V
1. Guaranteed by characterization results, not tested in production.
2. The maximum programming time is measured after 100K erase operations.

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Table 38. Flash memory programming with VPP

Symbol Parameter Conditions Min(1) Typ Max(1) Unit

tprog Double word programming - 16 100(2) µs

tERASE16KB Sector (16 KB) erase time TA = 0 to +40 °C - 230 -
tERASE64KB Sector (64 KB) erase time VDD = 3.3 V - 490 - ms
tERASE128KB Sector (128 KB) erase time VPP = 8.5 V - 875 -
tME Mass erase time - 6.9 - s
Vprog Programming voltage - 2.7 - 3.6 V
VPP VPP voltage range - 7 - 9 V
Minimum current sunk on
IPP - 10 - - mA
the VPP pin
Cumulative time during
tVPP(3) - - - 1 hour
which VPP is applied
1. Guaranteed by design, not tested in production.
2. The maximum programming time is measured after 100K erase operations.
3. VPP should only be connected during programming/erasing.

Table 39. Flash memory endurance and data retention

Value
Symbol Parameter Conditions Unit
Min(1)

TA = –40 to +85 °C (6 suffix versions)

NEND Endurance 10 kcycles
TA = –40 to +105 °C (7 suffix versions)
1 kcycle(2) at TA = 85 °C 30
(2)
tRET Data retention 1 kcycle at TA = 105 °C 10 Years
(2)
10 kcycles at TA = 55 °C 20
1. Guaranteed by characterization results, not tested in production.
2. Cycling performed over the whole temperature range.

6.3.13 EMC characteristics

Susceptibility tests are performed on a sample basis during device characterization.

Functional EMS (electromagnetic susceptibility)

While a simple application is executed on the device (toggling 2 LEDs through I/O ports).
the device is stressed by two electromagnetic events until a failure occurs. The failure is
indicated by the LEDs:
• Electrostatic discharge (ESD) (positive and negative) is applied to all device pins until
a functional disturbance occurs. This test is compliant with the IEC 61000-4-2 standard.
• FTB: A burst of fast transient voltage (positive and negative) is applied to VDD and VSS
through a 100 pF capacitor, until a functional disturbance occurs. This test is compliant
with the IEC 61000-4-4 standard.
A device reset allows normal operations to be resumed.

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The test results are given in Table 40. They are based on the EMS levels and classes
defined in application note AN1709.

Table 40. EMS characteristics

Level/
Symbol Parameter Conditions
Class

VDD = 3.3 V, LQFP176, TA =

Voltage limits to be applied on any I/O pin to
VFESD +25 °C, fHCLK = 120 MHz, conforms 2B
induce a functional disturbance
to IEC 61000-4-2
Fast transient voltage burst limits to be VDD = 3.3 V, LQFP176, TA =
VEFTB applied through 100 pF on VDD and VSS +25 °C, fHCLK = 120 MHz, conforms 4A
pins to induce a functional disturbance to IEC 61000-4-2

Designing hardened software to avoid noise problems

EMC characterization and optimization are performed at component level with a typical
application environment and simplified MCU software. It should be noted that good EMC
performance is highly dependent on the user application and the software in particular.
Therefore it is recommended that the user applies EMC software optimization and
prequalification tests in relation with the EMC level requested for his application.
Software recommendations
The software flowchart must include the management of runaway conditions such as:
• Corrupted program counter
• Unexpected reset
• Critical Data corruption (control registers...)
Prequalification trials
Most of the common failures (unexpected reset and program counter corruption) can be
reproduced by manually forcing a low state on the NRST pin or the Oscillator pins for 1
second.
To complete these trials, ESD stress can be applied directly on the device, over the range of
specification values. When unexpected behavior is detected, the software can be hardened
to prevent unrecoverable errors occurring (see application note AN1015).

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Electromagnetic Interference (EMI)

The electromagnetic field emitted by the device are monitored while a simple application,
executing EEMBC® code, is running. This emission test is compliant with SAE IEC61967-2
standard which specifies the test board and the pin loading.

Table 41. EMI characteristics

Max vs.
Monitored [fHSE/fCPU]
Symbol Parameter Conditions Unit
frequency band
25/120 MHz

0.1 to 30 MHz
VDD = 3.3 V, TA = 25 °C, LQFP176
package, conforming to SAE J1752/3 30 to 130 MHz 25 dBµV
EEMBC, code running with ART 130 MHz to 1GHz
enabled, peripheral clock disabled
SAE EMI Level 4 -
SEMI Peak level
VDD = 3.3 V, TA = 25 °C, LQFP176 0.1 to 30 MHz 28
package, conforming to SAE J1752/3 30 to 130 MHz 26 dBµV
EEMBC, code running with ART
enabled, PLL spread spectrum 130 MHz to 1GHz 22
enabled, peripheral clock disabled SAE EMI level 4 -

6.3.14 Absolute maximum ratings (electrical sensitivity)

Based on three different tests (ESD, LU) using specific measurement methods, the device is
stressed in order to determine its performance in terms of electrical sensitivity.

Electrostatic discharge (ESD)

Electrostatic discharges (a positive then a negative pulse separated by 1 second) are
applied to the pins of each sample according to each pin combination. The sample size
depends on the number of supply pins in the device (3 parts × (n+1) supply pins). This test
conforms to the JESD22-A114/C101 standard.

Table 42. ESD absolute maximum ratings

Maximum
Symbol Ratings Conditions Class Unit
value(1)

Electrostatic discharge
VESD(HBM) voltage (human body TA = +25 °C conforming to JESD22-A114 2 2000(2)
model)
V
Electrostatic discharge
VESD(CDM) voltage (charge device TA = +25 °C conforming to JESD22-C101 II 500
model)
1. Guaranteed by characterization results, not tested in production.
2. On VBAT pin, VESD(HBM) is limited to 1000 V.

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Static latch-up
Two complementary static tests are required on six parts to assess the latch-up
performance:
• A supply overvoltage is applied to each power supply pin
• A current injection is applied to each input, output and configurable I/O pin
These tests are compliant with EIA/JESD 78A IC latch-up standard.

Table 43. Electrical sensitivities

Symbol Parameter Conditions Class

LU Static latch-up class TA = +105 °C conforming to JESD78A II level A

6.3.15 I/O current injection characteristics

As a general rule, current injection to the I/O pins, due to external voltage below VSS or
above VDD (for standard, 3 V-capable I/O pins) should be avoided during normal product
operation. However, in order to give an indication of the robustness of the microcontroller in
cases when abnormal injection accidentally happens, susceptibility tests are performed on a
sample basis during device characterization.

Functional susceptibilty to I/O current injection

While a simple application is executed on the device, the device is stressed by injecting
current into the I/O pins programmed in floating input mode. While current is injected into
the I/O pin, one at a time, the device is checked for functional failures.
The failure is indicated by an out of range parameter: ADC error above a certain limit (>5
LSB TUE), out of spec current injection on adjacent pins or other functional failure (for
example reset, oscillator frequency deviation).
The test results are given in Table 44.

Table 44. I/O current injection susceptibility(1)

Functional susceptibility
Symbol Description Unit
Negative Positive
injection injection

Injected current on BOOT0 pin –0 NA

Injected current on NRST pin –0 NA
IINJ mA
Injected current on TTa pins: PA4 and PA5 –0 +5
Injected current on all FT pins –5 NA
1. NA stands for “not applicable”.

Note: It is recommended to add a Schottky diode (pin to ground) to analog pins which may
potentially inject negative currents.

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6.3.16 I/O port characteristics

General input/output characteristics
Unless otherwise specified, the parameters given in Table 49 are derived from tests
performed under the conditions summarized in Table 13: General operating conditions.
All I/Os are CMOS and TTL compliant.

Table 45. I/O static characteristics

Symbol Parameter Conditions Min Typ Max Unit

FT, TTa and NRST I/O 0.35VDD–0.04(1)

1.7 V≤VDD≤3.6 V - -
input low level voltage 0.3VDD(2)

VIL 1.75 V≤VDD ≤3.6 V, V

- -
BOOT0 I/O –40 °C≤TA ≤105 °C
0.1VDD+0.1(1)
input low level voltage 1.7 V≤VDD ≤3.6 V,
- -
0 °C≤TA ≤105 °C

FT, TTa and NRST I/O 0.45VDD+0.3(1)

1.7 V≤VDD≤3.6 V - -
input high level voltage(5) 0.7VDD(2)

VIH 1.75 V≤VDD ≤3.6 V, V

BOOT0 I/O –40 °C≤TA ≤105 °C
0.17VDD+0.7(1) - -
input high level voltage 1.7 V≤VDD ≤3.6 V,
0 °C≤TA ≤105 °C
FT, TTa and NRST I/O
1.7 V≤VDD≤3.6 V 0.45VDD+0.3(1) - -
input hysteresis
1.75 V≤VDD ≤3.6 V,
VHYS 10%VDDIO(1)(3) - - V
BOOT0 I/O –40 °C≤TA ≤105 °C
input hysteresis 1.7 V≤VDD ≤3.6 V,
100(1) - -
0 °C≤TA ≤105 °C
I/O input leakage current (4) VSS ≤VIN ≤VDD - - ±1
Ilkg µA
(5)
I/O FT input leakage current VIN = 5 V - - 3

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Table 45. I/O static characteristics (continued)

Symbol Parameter Conditions Min Typ Max Unit

All pins
except for
PA10/PB12 VIN = VSS 30 40 50
Weak pull-up (OTG_FS_ID,
RPU equivalent OTG_HS_ID)
resistor(6)
PA10/PB12
(OTG_FS_ID, - 7 10 14
OTG_HS_ID)
kΩ
All pins
except for
PA10/PB12 VIN = VDD 30 40 50
Weak pull-down (OTG_FS_ID,
RPD equivalent OTG_HS_ID)
resistor(7)
PA10/PB12
(OTG_FS_ID, - 7 10 14
OTG_HS_ID)
CIO(8) I/O pin capacitance - - 5 - pF
1. Guaranteed by design, not tested in production.
2. Guaranteed by tests in production.
3. With a minimum of 200 mV.
4. Leakage could be higher than the maximum value, if negative current is injected on adjacent pins, Refer to Table 44: I/O
current injection susceptibility
5. To sustain a voltage higher than VDD +0.3 V, the internal pull-up/pull-down resistors must be disabled. Leakage could be
higher than the maximum value, if negative current is injected on adjacent pins.Refer to Table 44: I/O current injection
susceptibility
6. Pull-up resistors are designed with a true resistance in series with a switchable PMOS. This PMOS contribution to the
series resistance is minimum (~10% order).
7. Pull-down resistors are designed with a true resistance in series with a switchable NMOS. This NMOS contribution to the
series resistance is minimum (~10% order).
8. Hysteresis voltage between Schmitt trigger switching levels. Based on characterization, not tested in production.

All I/Os are CMOS and TTL compliant (no software configuration required). Their
characteristics cover more than the strict CMOS-technology or TTL parameters. The
coverage of these requirements for FT I/Os is shown in Figure 36.

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Electrical characteristics STM32F21xxx

Figure 36. FT I/O input characteristics

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Output driving current

The GPIOs (general purpose input/outputs) can sink or source up to ±8 mA, and sink or
source up to ±20 mA (with a relaxed VOL/VOH) except PC13, PC14 and PC15 which can
sink or source up to ±3mA. When using the PC13 to PC15 GPIOs in output mode, the speed
should not exceed 2 MHz with a maximum load of 30 pF.
In the user application, the number of I/O pins which can drive current must be limited to
respect the absolute maximum rating specified in Section 6.2:
• The sum of the currents sourced by all the I/Os on VDD, plus the maximum Run
consumption of the MCU sourced on VDD, cannot exceed the absolute maximum rating
IVDD (see Table 11).
• The sum of the currents sunk by all the I/Os on VSS plus the maximum Run
consumption of the MCU sunk on VSS cannot exceed the absolute maximum rating
IVSS (see Table 11).

Output voltage levels

Unless otherwise specified, the parameters given in Table 46 are derived from tests
performed under ambient temperature and VDD supply voltage conditions summarized in
Table 13. All I/Os are CMOS and TTL compliant.

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Table 46. Output voltage characteristics(1)

Symbol Parameter Conditions Min Max Unit

Output low level voltage for an I/O pin

VOL(2) CMOS ports - 0.4
when 8 pins are sunk at same time
IIO = +8 mA V
Output high level voltage for an I/O pin
VOH(3) 2.7 V < VDD < 3.6 V VDD–0.4 -
when 8 pins are sourced at same time
Output low level voltage for an I/O pin
VOL (2) TTL ports - 0.4
when 8 pins are sunk at same time
IIO =+ 8mA V
Output high level voltage for an I/O pin
VOH (3) 2.7 V < VDD < 3.6 V 2.4 -
when 8 pins are sourced at same time
Output low level voltage for an I/O pin
VOL(2)(4) - 1.3
when 8 pins are sunk at same time IIO = +20 mA
V
Output high level voltage for an I/O pin 2.7 V < VDD < 3.6 V
VOH(3)(4) VDD–1.3 -
when 8 pins are sourced at same time
Output low level voltage for an I/O pin
VOL(2)(4) - 0.4
when 8 pins are sunk at same time IIO = +6 mA
V
Output high level voltage for an I/O pin 2 V < VDD < 2.7 V
VOH(3)(4) VDD–0.4 -
when 8 pins are sourced at same time
1. PC13, PC14, PC15 and PI8 are supplied through the power switch. Since the switch only sinks a limited
amount of current (3 mA), the use of GPIOs PC13 to PC15 and PI8 in output mode is limited: the speed
should not exceed 2 MHz with a maximum load of 30 pF and these I/Os must not be used as a current
source (e.g. to drive an LED).
2. The IIO current sunk by the device must always respect the absolute maximum rating specified in Table 11
and the sum of IIO (I/O ports and control pins) must not exceed IVSS.
3. The IIO current sourced by the device must always respect the absolute maximum rating specified in
Table 11 and the sum of IIO (I/O ports and control pins) must not exceed IVDD.
4. Guaranteed by characterization results, not tested in production.

Input/output AC characteristics
The definition and values of input/output AC characteristics are given in Figure 37 and
Table 47, respectively.
Unless otherwise specified, the parameters given in Table 47 are derived from tests
performed under the ambient temperature and VDD supply voltage conditions summarized
in Table 13.

Table 47. I/O AC characteristics(1)

OSPEEDRy
[1:0] bit Symbol Parameter Conditions Min Typ Max Unit
value(1)

CL = 50 pF, VDD > 2.70 V - - 4

CL = 50 pF, VDD > 1.8 V - - 2
fmax(IO)out Maximum frequency(2) MHz
CL = 10 pF, VDD > 2.70 V - - 8
00
CL = 10 pF, VDD > 1.8 V - - 4
Output high to low level fall
tf(IO)out/ CL = 50 pF, VDD = 1.8 V to
time and output low to high - - 100 ns
tr(IO)out 3.6 V
level rise time

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Electrical characteristics STM32F21xxx

Table 47. I/O AC characteristics(1) (continued)

OSPEEDRy
[1:0] bit Symbol Parameter Conditions Min Typ Max Unit
value(1)

CL = 50 pF, VDD > 2.70 V - - 25

CL = 50 pF, VDD > 1.8 V - - 12.5
fmax(IO)out Maximum frequency(2) MHz
CL = 10 pF, VDD > 2.70 V - - 50(3)
CL = 10 pF, VDD > 1.8 V - - 20
01
CL = 50 pF, VDD >2.7 V - - 10
Output high to low level fall CL = 50 pF, VDD > 1.8 V - - 20
tf(IO)out/
time and output low to high ns
tr(IO)out CL = 10 pF, VDD > 2.70 V - - 6
level rise time
CL = 10 pF, VDD > 1.8 V - - 10
CL = 40 pF, VDD > 2.70 V - - 25
CL = 40 pF, VDD > 1.8 V - - 20
fmax(IO)out Maximum frequency(2) MHz
CL = 10 pF, VDD > 2.70 V - - 100(3)
CL = 10 pF, VDD > 1.8 V - - 50(3)
10
CL = 40 pF, VDD > 2.70 V - - 6
Output high to low level fall CL = 40 pF, VDD > 1.8 V - - 10
tf(IO)out/
time and output low to high ns
tr(IO)out CL = 10 pF, VDD > 2.70 V - - 4
level rise time
CL = 10 pF, VDD > 1.8 V - -3 6
CL = 30 pF, VDD > 2.70 V - - 100(3)
CL = 30 pF, VDD > 1.8 V - - 50(3)
fmax(IO)out Maximum frequency(2) MHz
CL = 10 pF, VDD > 2.70 V - - 120(3)
CL = 10 pF, VDD > 1.8 V - - 100(3)
11
CL = 30 pF, VDD > 2.70 V - - 4
Output high to low level fall CL = 30 pF, VDD > 1.8 V - - 6
tf(IO)out/
time and output low to high ns
tr(IO)out CL = 10 pF, VDD > 2.70 V - - 2.5
level rise time
CL = 10 pF, VDD > 1.8 V - - 4
Pulse width of external
- tEXTIpw signals detected by the - 10 - - ns
EXTI controller
1. The I/O speed is configured using the OSPEEDRy[1:0] bits. Refer to the STM32F20/21xxx reference manual for a
description of the GPIOx_SPEEDR GPIO port output speed register.
2. The maximum frequency is defined in Figure 37.
3. For maximum frequencies above 50 MHz and VDD above 2.4 V, the compensation cell should be used.

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Figure 37. I/O AC characteristics definition

 

 

 

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6.3.17 NRST pin characteristics

The NRST pin input driver uses CMOS technology. It is connected to a permanent pull-up
resistor, RPU (see Table 48).
Unless otherwise specified, the parameters given in Table 48 are derived from tests
performed under the ambient temperature and VDD supply voltage conditions summarized
in Table 13.

Table 48. NRST pin characteristics

Symbol Parameter Conditions Min Typ Max Unit

RPU Weak pull-up equivalent resistor(1) VIN = VSS 30 40 50 kΩ

VF(NRST)(2) NRST Input filtered pulse - - - 100 ns
VNF(NRST)(2) NRST Input not filtered pulse VDD > 2.7 V 300 - - ns
TNRST_OUT Generated reset pulse duration Internal Reset source 20 - - µs
1. The pull-up is designed with a true resistance in series with a switchable PMOS. This PMOS contribution to the series
resistance must be minimum (~10% order).
2. Guaranteed by design, not tested in production.

Figure 38. Recommended NRST pin protection

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1. The reset network protects the device against parasitic resets.

2. The user must ensure that the level on the NRST pin can go below the VIL(NRST) max level specified in
Table 48. Otherwise the reset is not taken into account by the device.

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6.3.18 TIM timer characteristics

The parameters given in Table 49 and Table 50 are guaranteed by design.
Refer to Section 6.3.16: I/O port characteristics for details on the input/output alternate
function characteristics (output compare, input capture, external clock, PWM output).

Table 49. Characteristics of TIMx connected to the APB1 domain(1)

Symbol Parameter Conditions Min Max Unit

AHB/APB1 1 - tTIMxCLK
prescaler distinct
from 1, fTIMxCLK =
16.7 - ns
tres(TIM) Timer resolution time 60 MHz
AHB/APB1 1 - tTIMxCLK
prescaler = 1,
fTIMxCLK = 30 MHz 33.3 - ns

Timer external clock 0 fTIMxCLK/2 MHz

fEXT
frequency on CH1 to CH4 0 30 MHz
ResTIM Timer resolution - 16/32 bit
16-bit counter clock period 1 65536 tTIMxCLK
when internal clock is fTIMxCLK = 60 MHz
selected 0.0167 1092 µs
tCOUNTER APB1= 30 MHz
32-bit counter clock period 1 - tTIMxCLK
when internal clock is
selected 0.0167 71582788 µs

- 65536 × 65536 tTIMxCLK

tMAX_COUNT Maximum possible count
- 71.6 s
1. TIMx is used as a general term to refer to the TIM2, TIM3, TIM4, TIM5, TIM6, TIM7, and TIM12 timers.

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Table 50. Characteristics of TIMx connected to the APB2 domain(1)

Symbol Parameter Conditions Min Max Unit

AHB/APB2 1 - tTIMxCLK
prescaler distinct
from 1, fTIMxCLK =
8.3 - ns
tres(TIM) Timer resolution time 120 MHz
AHB/APB2 1 - tTIMxCLK
prescaler = 1,
fTIMxCLK = 60 MHz 16.7 - ns

Timer external clock 0 fTIMxCLK/2 MHz

fEXT
frequency on CH1 to CH4 0 60 MHz
ResTIM Timer resolution - 16 bit
fTIMxCLK = 120 MHz
16-bit counter clock period 1 65536 tTIMxCLK
tCOUNTER when internal clock is APB2 = 60 MHz
selected 0.0083 546 µs

- 65536 × 65536 tTIMxCLK

tMAX_COUNT Maximum possible count
- 35.79 s
1. TIMx is used as a general term to refer to the TIM1, TIM8, TIM9, TIM10, and TIM11 timers.

6.3.19 Communications interfaces

I2C interface characteristics
STM32F215xx and STM32F217xx I2C interface meets the requirements of the standard I2C
communication protocol with the following restrictions: the I/O pins SDA and SCL are
mapped to are not “true” open-drain. When configured as open-drain, the PMOS connected
between the I/O pin and VDD is disabled, but is still present.
The I2C characteristics are described in Table 51. Refer also to Section 6.3.16: I/O port
characteristics for more details on the input/output alternate function characteristics (SDA
and SCL).

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Electrical characteristics STM32F21xxx

Table 51. I2C characteristics

Standard mode
Fast mode I2C(1)(2)
I2C(1)(2)
Symbol Parameter Unit
Min Max Min Max

tw(SCLL) SCL clock low time 4.7 - 1.3 -

µs
tw(SCLH) SCL clock high time 4.0 - 0.6 -
tsu(SDA) SDA setup time 250 - 100 -
th(SDA) SDA data hold time - 3450(3) - 900(3)
tr(SDA) ns
SDA and SCL rise time - 1000 - 300
tr(SCL)
tf(SDA)
SDA and SCL fall time - 300 - 300
tf(SCL)
th(STA) Start condition hold time 4.0 - 0.6 -
Repeated Start condition µs
tsu(STA) 4.7 - 0.6 -
setup time
tsu(STO) Stop condition setup time 4.0 - 0.6 - μs
Stop to Start condition time
tw(STO:STA) 4.7 - 1.3 - μs
(bus free)
Capacitive load for each bus
Cb - 400 - 400 pF
line
Pulse width of the spikes
tSP that are suppressed by the 0 50(4) 0 50 ns
analog filter
1. Guaranteed by design, not tested in production.
2. fPCLK1 must be at least 2 MHz to achieve standard mode I2C frequencies. It must be at least 4 MHz to
achieve fast mode I2C frequencies, and a multiple of 10 MHz to reach the 400 kHz maximum I2C fast mode
clock.
3. The maximum Data hold time has only to be met if the interface does not stretch the low period of the SCL
signal.
4. The minimum width of the spikes filtered by the analog filter is above tSP(max).

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Figure 39. I2C bus AC waveforms and measurement circuit

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1. RS= series protection resistor.

2. RP = external pull-up resistor.
3. VDD_I2C is the I2C bus power supply.

Table 52. SCL frequency (fPCLK1= 30 MHz.,VDD = 3.3 V)(1)(2)

I2C_CCR value
fSCL (kHz)
RP = 4.7 kΩ

400 0x8019
300 0x8021
200 0x8032
100 0x0096
50 0x012C
20 0x02EE
1. RP = External pull-up resistance, fSCL = I2C speed,
2. For speeds around 200 kHz, the tolerance on the achieved speed is of ±5%. For other speed ranges, the
tolerance on the achieved speed ±2%. These variations depend on the accuracy of the external
components used to design the application.

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Electrical characteristics STM32F21xxx

I2S - SPI interface characteristics

Unless otherwise specified, the parameters given in Table 53 for SPI or in Table 54 for I2S
are derived from tests performed under the ambient temperature, fPCLKx frequency and VDD
supply voltage conditions summarized in Table 13.
Refer to Section 6.3.16: I/O port characteristics for more details on the input/output alternate
function characteristics (NSS, SCK, MOSI, MISO for SPI and WS, CK, SD for I2S).

Table 53. SPI characteristics

Symbol Parameter Conditions Min Max Unit

fSCK SPI1 master/slave mode - 30

SPI clock frequency MHz
1/tc(SCK) SPI2/SPI3 master/slave mode - 15

tr(SCL) SPI clock rise and fall Capacitive load: C = 30 pF,

- 8 ns
tf(SCL) time fPCLK = 30 MHz
SPI slave input clock
DuCy(SCK) Slave mode 30 70 %
duty cycle
tsu(NSS)(1) NSS setup time Slave mode 4tPCLK -
th(NSS)(1) NSS hold time Slave mode 2tPCLK -
(1)
tw(SCLH) Master mode, fPCLK = 30 MHz,
SCK high and low time tPCLK-3 tPCLK+3
tw(SCLL)(1) presc = 2

tsu(MI) (1) Master mode 5 -

Data input setup time
tsu(SI)(1) Slave mode 5 -

th(MI) (1) Master mode 5 -

Data input hold time
th(SI)(1) Slave mode 4 -
ns
Data output access
ta(SO)(1)(2) Slave mode, fPCLK = 30 MHz 0 3tPCLK
time
Data output disable
tdis(SO)(1)(3) Slave mode 2 10
time
tv(SO) (1) Data output valid time Slave mode (after enable edge) - 25
tv(MO)(1) Data output valid time Master mode (after enable edge) - 5
th(SO) (1) Slave mode (after enable edge) 15 -
Data output hold time
(1)
th(MO) Master mode (after enable edge) 2 -
1. Guaranteed by characterization results, not tested in production.
2. Min time is for the minimum time to drive the output and the max time is for the maximum time to validate
the data.
3. Min time is for the minimum time to invalidate the output and the max time is for the maximum time to put
the data in Hi-Z

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STM32F21xxx Electrical characteristics

Figure 40. SPI timing diagram - slave mode and CPHA = 0

NSS input

tc(SCK)

tSU(NSS) th(NSS)

CPHA= 0
SCK Input

CPOL=0
tw(SCKH)
CPHA= 0 tw(SCKL)
CPOL=1

ta(SO) tv(SO) th(SO) tr(SCK) tdis(SO)

tf(SCK)
MISO
OUT P UT MS B O UT BI T6 OUT LSB OUT
tsu(SI)
MOSI
M SB IN B I T1 IN LSB IN
I NPUT
th(SI)
ai14134c

Figure 41. SPI timing diagram - slave mode and CPHA = 1

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DocID17050 Rev 13 115/180

179
Electrical characteristics STM32F21xxx

Figure 42. SPI timing diagram - master mode

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STM32F21xxx Electrical characteristics

Table 54. I2S characteristics

Symbol Parameter Conditions Min Max Unit

Master, 16-bit data,

fCK audio frequency = 48 kHz, main 1.23 1.24
I2S clock frequency clock disabled MHz
1/tc(CK)
Slave 0 64FS(1)
tr(CK)
I2S clock rise and fall time Capacitive load CL = 50 pF - (2)
tf(CK)
tv(WS) (3) WS valid time Master 0.3 -
(3)
th(WS) WS hold time Master 0 -
(3)
tsu(WS) WS setup time Slave 3 -
th(WS) (3) WS hold time Slave 0 -
(3)
tw(CKH)
CK high and low time Master fPCLK= 30 MHz 396 -
tw(CKL) (3)
tsu(SD_MR) (3) Master receiver 45
Data input setup time -
tsu(SD_SR) (3) Slave receiver 0 ns
th(SD_MR)(3)(4) Master receiver: fPCLK= 30 MHz, 13
Data input hold time -
th(SD_SR) (3)(4) Slave receiver: fPCLK= 30 MHz 0
Slave transmitter (after enable
tv(SD_ST) (3)(4) Data output valid time - 30
edge)
Slave transmitter (after enable
th(SD_ST) (3) Data output hold time 10 -
edge)
Master transmitter (after enable
tv(SD_MT) (3)(4) Data output valid time - 6
edge)
Master transmitter (after enable
th(SD_MT) (3) Data output hold time 0 -
edge)
1. FS is the sampling frequency. Refer to the I2S section of the STM32F20xxx/21xxx reference manual for more details. fCK
values reflect only the digital peripheral behavior which leads to a minimum of (I2SDIV/(2*I2SDIV+ODD), a maximum of
(I2SDIV+ODD)/(2*I2SDIV+ODD) and FS maximum values for each mode/condition.
2. Refer to Table 47: I/O AC characteristics.
3. Guaranteed by design, not tested in production.
4. Depends on fPCLK. For example, if fPCLK=8 MHz, then TPCLK = 1/fPLCLK =125 ns.

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Electrical characteristics STM32F21xxx

Figure 43. I2S slave timing diagram (Philips protocol)(1)

tc(CK)

CK Input CPOL = 0

CPOL = 1

tw(CKH) tw(CKL) th(WS)

WS input

tsu(WS) tv(SD_ST) th(SD_ST)

SDtransmit
LSB transmit(2) MSB transmit Bitn transmit LSB transmit

tsu(SD_SR) th(SD_SR)

SDreceive LSB receive(2) MSB receive Bitn receive LSB receive

ai14881b

1. LSB transmit/receive of the previously transmitted byte. No LSB transmit/receive is sent before the first
byte.

Figure 44. I2S master timing diagram (Philips protocol)(1)

tf(CK) tr(CK)

tc(CK)
CK output

CPOL = 0
tw(CKH)

CPOL = 1
tv(WS) tw(CKL) th(WS)

WS output

tv(SD_MT) th(SD_MT)

SDtransmit LSB transmit(2) MSB transmit Bitn transmit LSB transmit

tsu(SD_MR) th(SD_MR)

SDreceive LSB receive(2) MSB receive Bitn receive LSB receive

ai14884b

1. Guaranteed by characterization results, not tested in production.

2. LSB transmit/receive of the previously transmitted byte. No LSB transmit/receive is sent before the first
byte.

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STM32F21xxx Electrical characteristics

USB OTG FS characteristics

The USB OTG interface is USB-IF certified (Full-Speed). This interface is present in both the
USB OTG HS and USB OTG FS controllers.

Table 55. USB OTG FS startup time

Symbol Parameter Max Unit

tSTARTUP(1) USB OTG FS transceiver startup time 1 µs

1. Guaranteed by design, not tested in production.

Table 56. USB OTG FS DC electrical characteristics

Symbol Parameter Conditions Min(1) Typ Max(1) Unit

USB OTG FS operating

VDD 3.0(2) - 3.6 V
voltage
I(USB_FS_DP/DM,
VDI(3) Differential input sensitivity 0.2 - -
Input USB_HS_DP/DM)
levels Differential common mode
VCM(3) Includes VDI range 0.8 - 2.5 V
range
Single ended receiver
VSE(3) 1.3 - 2.0
threshold

Output VOL Static output level low RL of 1.5 kΩ to 3.6 V(4) - - 0.3
V
levels VOH Static output level high RL of 15 kΩ to VSS(4) 2.8 - 3.6
PA11, PA12, PB14, PB15
(USB_FS_DP/DM, 17 21 24
USB_HS_DP/DM)
RPD VIN = VDD
PA9, PB13
(OTG_FS_VBUS, 0.65 1.1 2.0
OTG_HS_VBUS) kΩ
PA12, PB15 (USB_FS_DP,
VIN = VSS 1.5 1.8 2.1
USB_HS_DP)
RPU PA9, PB13
(OTG_FS_VBUS, VIN = VSS 0.25 0.37 0.55
OTG_HS_VBUS)
1. All the voltages are measured from the local ground potential.
2. The STM32F215xx and STM32F217xx USB OTG FS functionality is ensured down to 2.7 V but not the full
USB OTG FS electrical characteristics which are degraded in the 2.7-to-3.0 V VDD voltage range.
3. Guaranteed by design, not tested in production.
4. RL is the load connected on the USB OTG FS drivers

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Electrical characteristics STM32F21xxx

Figure 45. USB OTG FS timings: definition of data signal rise and fall time
Crossover
points
Differen tial
Data L ines
VCRS

VS S
tf tr
ai14137

Table 57. USB OTG FS electrical characteristics(1)

Driver characteristics

Symbol Parameter Conditions Min Max Unit

tr Rise time(2) CL = 50 pF 4 20 ns
tf Fall time(2) CL = 50 pF 4 20 ns
trfm Rise/fall time matching tr/tf 90 110 %
VCRS Output signal crossover voltage - 1.3 2.0 V
1. Guaranteed by design, not tested in production.
2. Measured from 10% to 90% of the data signal. For more detailed informations, refer to USB Specification -
Chapter 7 (version 2.0).

USB HS characteristics
Table 58 shows the USB HS operating voltage.

Table 58. USB HS DC electrical characteristics

Symbol Parameter Min(1) Max(1) Unit

Input level VDD USB OTG HS operating voltage 2.7 3.6 V

1. All the voltages are measured from the local ground potential.

Table 59. Clock timing parameters

Parameter(1) Symbol Min Nominal Max Unit

Frequency (first transition) 8-bit ±10% FSTART_8BIT 54 60 66 MHz

Frequency (steady state) ±500 ppm FSTEADY 59.97 60 60.03 MHz
Duty cycle (first transition) 8-bit ±10% DSTART_8BIT 40 50 60 %
Duty cycle (steady state) ±500 ppm DSTEADY 49.975 50 50.025 %
Time to reach the steady state frequency and
TSTEADY - - 1.4 ms
duty cycle after the first transition

Clock startup time after the Peripheral TSTART_DEV - - 5.6

ms
de-assertion of SuspendM Host TSTART_HOST - - -
PHY preparation time after the first transition
TPREP - - - µs
of the input clock
1. Guaranteed by design, not tested in production.

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STM32F21xxx Electrical characteristics

Figure 46. ULPI timing diagram

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Table 60. ULPI timing

Value(1)
Symbol Parameter Unit
Min Max

Control in (ULPI_DIR) setup time - 2.0

tSC
Control in (ULPI_NXT) setup time - 1.5
tHC Control in (ULPI_DIR, ULPI_NXT) hold time 0 -
tSD Data in setup time - 2.0 ns
tHD Data in hold time 0 -
tDC Control out (ULPI_STP) setup time and hold time - 9.2
tDD Data out available from clock rising edge - 10.7
1. VDD = 2.7 V to 3.6 V and TA = –40 to 85 °C.

Ethernet characteristics
Table 61 shows the Ethernet operating voltage.

Table 61. Ethernet DC electrical characteristics

Symbol Parameter Min(1) Max(1) Unit

Input level VDD Ethernet operating voltage 2.7 3.6 V

1. All the voltages are measured from the local ground potential.

Table 62 gives the list of Ethernet MAC signals for the SMI (station management interface)
and Figure 47 shows the corresponding timing diagram.

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Electrical characteristics STM32F21xxx

Figure 47. Ethernet SMI timing diagram

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Table 62. Dynamics characteristics: Ethernet MAC signals for SMI

Symbol Rating Min Typ Max Unit

tMDC MDC cycle time (2.38 MHz) 411 420 425 ns

td(MDIO) MDIO write data valid time 6 10 13 ns
tsu(MDIO) Read data setup time 12 - - ns
th(MDIO) Read data hold time 0 - - ns

Table 63 gives the list of Ethernet MAC signals for the RMII and Figure 48 shows the
corresponding timing diagram.

Figure 48. Ethernet RMII timing diagram

RMII_REF_CLK

td(TXEN)
td(TXD)

RMII_TX_EN
RMII_TXD[1:0]
tsu(RXD) tih(RXD)
tsu(CRS) tih(CRS)

RMII_RXD[1:0]
RMII_CRS_DV

ai15667

Table 63. Dynamics characteristics: Ethernet MAC signals for RMII

Symbol Rating Min Typ Max Unit

tsu(RXD) Receive data setup time 1 - -

tih(RXD) Receive data hold time 1.5 - -
tsu(CRS) Carrier sense set-up time 0 - -
ns
tih(CRS) Carrier sense hold time 2 - -
td(TXEN) Transmit enable valid delay time 9 11 13
td(TXD) Transmit data valid delay time 9 11.5 14

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STM32F21xxx Electrical characteristics

Table 64 gives the list of Ethernet MAC signals for MII and Figure 48 shows the
corresponding timing diagram.

Figure 49. Ethernet MII timing diagram

MII_RX_CLK
tsu(RXD) tih(RXD)
tsu(ER) tih(ER)
tsu(DV) tih(DV)
MII_RXD[3:0]
MII_RX_DV
MII_RX_ER

MII_TX_CLK

td(TXEN)
td(TXD)

MII_TX_EN
MII_TXD[3:0]

ai15668

Table 64. Dynamics characteristics: Ethernet MAC signals for MII

Symbol Rating Min Typ Max Unit

tsu(RXD) Receive data setup time 7.5 - - ns

tih(RXD) Receive data hold time 1 - - ns
tsu(DV) Data valid setup time 4 - - ns
tih(DV) Data valid hold time 0 - - ns
tsu(ER) Error setup time 3.5 - - ns
tih(ER) Error hold time 0 - - ns
td(TXEN) Transmit enable valid delay time - 11 14 ns
td(TXD) Transmit data valid delay time - 11 14 ns

CAN (controller area network) interface

Refer to Section 6.3.16: I/O port characteristics for more details on the input/output alternate
function characteristics (CANTX and CANRX).

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Electrical characteristics STM32F21xxx

6.3.20 12-bit ADC characteristics

Unless otherwise specified, the parameters given in Table 65 are derived from tests
performed under the ambient temperature, fPCLK2 frequency and VDDA supply voltage
conditions summarized in Table 13.

Table 65. ADC characteristics

Symbol Parameter Conditions Min Typ Max Unit

VDDA Power supply - 1.8 - 3.6 V

VREF+ Positive reference voltage - 1.8(1) - VDDA V
VDDA = 1.8 to 2.4 V 0.6 - 15 MHz
fADC ADC clock frequency
VDDA = 2.4 to 3.6 V 0.6 - 30 MHz
fADC = 30 MHz with
- - 1764 kHz
fTRIG(2) External trigger frequency 12-bit resolution
- - - 17 1/fADC
0 (VSSA or VREF-
VAIN Conversion voltage range(3) - - VREF+ V
tied to ground)
See Equation 1 for
RAIN(2) External input impedance - - 50 kΩ
details
RADC(2)(4) Sampling switch resistance - 1.5 - 6 kΩ
Internal sample and hold
CADC(2) - - 4 - pF
capacitor

Injection trigger conversion fADC = 30 MHz - - 0.100 µs

tlat(2)
latency - - - 3(5) 1/fADC
fADC = 30 MHz - - 0.067 µs
tlatr(2) Regular trigger conversion latency
- - - 2(5) 1/fADC
fADC = 30 MHz 0.100 - 16 µs
tS(2) Sampling time
- 3 - 480 1/fADC
tSTAB(2) Power-up time - - 2 3 µs
fADC = 30 MHz
0.5 - 16.40 µs
12-bit resolution
fADC = 30 MHz
0.43 - 16.34 µs
10-bit resolution
Total conversion time (including fADC = 30 MHz
tCONV(2) 0.37 - 16.27 µs
sampling time) 8-bit resolution
fADC = 30 MHz
0.3 - 16.20 µs
6-bit resolution
9 to 492 (tS for sampling +n-bit resolution for successive
1/fADC
approximation)

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STM32F21xxx Electrical characteristics

Table 65. ADC characteristics (continued)

Symbol Parameter Conditions Min Typ Max Unit

12-bit resolution
- - 2 Msps
Single ADC
12-bit resolution
Sampling rate Interleave Dual ADC - - 3.75 Msps
fS(2)
(fADC = 30 MHz) mode
12-bit resolution
Interleave Triple ADC - - 6 Msps
mode
ADC VREF DC current
IVREF+(2) - - 300 500 µA
consumption in conversion mode
ADC VDDA DC current
IVDDA(2) - - 1.6 1.8 mA
consumption in conversion mode
1. It is recommended to maintain the voltage difference between VREF+ and VDDA below 1.8 V.
2. Guaranteed by characterization results, not tested in production.
3. VREF+ is internally connected to VDDA and VREF- is internally connected to VSSA.
4. RADC maximum value is given for VDD=1.8 V, and minimum value for VDD=3.3 V.
5. For external triggers, a delay of 1/fPCLK2 must be added to the latency specified in Table 65.

Equation 1: RAIN max formula

( k – 0.5 )
R AIN - – R ADC
= ---------------------------------------------------------------
N+2
f ADC × C ADC × ln ( 2 )

The formula above (Equation 1) is used to determine the maximum external impedance
allowed for an error below 1/4 of LSB. N = 12 (from 12-bit resolution) and k is the number of
sampling periods defined in the ADC_SMPR1 register.

Table 66. ADC accuracy (1)

a

Symbol Parameter Test conditions Typ Max(2) Unit

ET Total unadjusted error ±2 ±5

EO Offset error ±1.5 ±2.5
fPCLK2 = 60 MHz,
EG Gain error fADC = 30 MHz, RAIN < 10 kΩ, ±1.5 ±3 LSB
VDDA = 1.8 to 3.6 V
ED Differential linearity error ±1 ±2
EL Integral linearity error ±1.5 ±3
1. Better performance could be achieved in restricted VDD, frequency and temperature ranges.
2. Guaranteed by characterization results, not tested in production.

Note: ADC accuracy vs. negative injection current: injecting a negative current on any analog
input pins should be avoided as this significantly reduces the accuracy of the conversion
being performed on another analog input. It is recommended to add a Schottky diode (pin to
ground) to analog pins which may potentially inject negative currents.
Any positive injection current within the limits specified for IINJ(PIN) and ΣIINJ(PIN) in
Section 6.3.16 does not affect the ADC accuracy.

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Electrical characteristics STM32F21xxx

Figure 50. ADC accuracy characteristics

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2. Ideal transfer curve.
3. End point correlation line.
4. ET = Total Unadjusted Error: maximum deviation between the actual and the ideal transfer curves.
EO = Offset Error: deviation between the first actual transition and the first ideal one.
EG = Gain Error: deviation between the last ideal transition and the last actual one.
ED = Differential Linearity Error: maximum deviation between actual steps and the ideal one.
EL = Integral Linearity Error: maximum deviation between any actual transition and the end point
correlation line.

Figure 51. Typical connection diagram using the ADC

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1. Refer to Table 65 for the values of RAIN, RADC and CADC.

2. Cparasitic represents the capacitance of the PCB (dependent on soldering and PCB layout quality) plus the
pad capacitance (roughly 7 pF). A high Cparasitic value downgrades conversion accuracy. To remedy this,
fADC should be reduced.

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STM32F21xxx Electrical characteristics

General PCB design guidelines

Power supply decoupling should be performed as shown in Figure 52 or Figure 53,
depending on whether VREF+ is connected to VDDA or not. The 10 nF capacitors should be
ceramic (good quality). They should be placed them as close as possible to the chip.

Figure 52. Power supply and reference decoupling (VREF+ not connected to VDDA)

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1. VREF+ and VREF– inputs are both available on UFBGA176 package. VREF+ is also available on all packages
except for LQFP64. When VREF+ and VREF– are not available, they are internally connected to VDDA and
VSSA.

DocID17050 Rev 13 127/180

179
Electrical characteristics STM32F21xxx

Figure 53. Power supply and reference decoupling (VREF+ connected to VDDA)

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1. VREF+ and VREF– inputs are both available on UFBGA176 package. VREF+ is also available on all packages
except for LQFP64. When VREF+ and VREF– are not available, they are internally connected to VDDA and
VSSA.

6.3.21 DAC electrical characteristics

Table 67. DAC characteristics

Symbol Parameter Min Typ Max Unit Comments

VDDA Analog supply voltage 1.8 - 3.6 V -

VREF+ Reference supply voltage 1.8 - 3.6 V VREF+ ≤VDDA

VSSA Ground 0 - 0 V -
Resistive load with buffer
RLOAD(1) 5 - - kΩ -
ON
When the buffer is OFF, the Minimum
Impedance output with
RO(1) - - 15 kΩ resistive load between DAC_OUT and
buffer OFF
VSS to have a 1% accuracy is 1.5 MΩ
Maximum capacitive load at DAC_OUT
CLOAD(1) Capacitive load - - 50 pF
pin (when the buffer is ON).
It gives the maximum output excursion
DAC_OUT Lower DAC_OUT voltage of the DAC.
0.2 - - V
min(1) with buffer ON
It corresponds to 12-bit input code
(0x0E0) to (0xF1C) at VREF+ = 3.6 V
DAC_OUT Higher DAC_OUT voltage and (0x1C7) to (0xE38) at VREF+ =
- - VDDA – 0.2 V
max(1) with buffer ON 1.8 V

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STM32F21xxx Electrical characteristics

Table 67. DAC characteristics (continued)

Symbol Parameter Min Typ Max Unit Comments

DAC_OUT Lower DAC_OUT voltage

- 0.5 - mV
min(1) with buffer OFF It gives the maximum output excursion
DAC_OUT Higher DAC_OUT voltage of the DAC.
- - VREF+ – 1LSB V
max(1) with buffer OFF
With no load, worst code (0x800) at
- 170 240 VREF+ = 3.6 V in terms of DC
DAC DC VREF current consumption on the inputs
IVREF+(3) consumption in quiescent µA
mode (Standby mode) With no load, worst code (0xF1C) at
- 50 75 VREF+ = 3.6 V in terms of DC
consumption on the inputs
With no load, middle code (0x800) on
- 280 380 µA
DAC DC VDDA current the inputs
IDDA(3) consumption in quiescent With no load, worst code (0xF1C) at
mode(2) - 475 625 µA VREF+ = 3.6 V in terms of DC
consumption on the inputs

Given for the DAC in 10-bit

Differential non linearity - - ±0.5 LSB
configuration.
DNL(3) Difference between two
consecutive code-1LSB) Given for the DAC in 12-bit
- - ±2 LSB
configuration.
Integral non linearity Given for the DAC in 10-bit
- - ±1 LSB
(difference between configuration.
measured value at Code i
INL(3) and the value at Code i on
a line drawn between Given for the DAC in 12-bit
- - ±4 LSB
Code 0 and last Code configuration.
1023)
- - ±10 mV -
Offset error
(difference between Given for the DAC in 10-bit at VREF+ =
- - ±3 LSB
Offset(3) measured value at Code 3.6 V
(0x800) and the ideal
Given for the DAC in 12-bit at VREF+ =
value = VREF+/2) - - ±12 LSB
3.6 V
Gain Given for the DAC in 12-bit
Gain error - - ±0.5 %
error(3) configuration
Settling time (full scale: for
a 10-bit input code
transition between the
CLOAD ≤ 50 pF,
tSETTLING(3) lowest and the highest - 3 6 µs
RLOAD ≥ 5 kΩ
input codes when
DAC_OUT reaches final
value ±4LSB
Total Harmonic Distortion CLOAD ≤ 50 pF,
THD(3) - - - dB
Buffer ON RLOAD ≥ 5 kΩ

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Electrical characteristics STM32F21xxx

Table 67. DAC characteristics (continued)

Symbol Parameter Min Typ Max Unit Comments

Max frequency for a

correct DAC_OUT change
Update CLOAD ≤ 50 pF,
when small variation in the - - 1 MS/s
rate(1) RLOAD ≥ 5 kΩ
input code (from code i to
i+1LSB)
Wakeup time from off state CLOAD ≤ 50 pF, RLOAD ≥ 5 kΩ
tWAKEUP(3) (Setting the ENx bit in the - 6.5 10 µs input code between lowest and highest
DAC Control register) possible ones.
Power supply rejection
PSRR+ (1) ratio (to VDDA) (static DC - –67 –40 dB No RLOAD, CLOAD = 50 pF
measurement)
1. Guaranteed by design, not tested in production.
2. The quiescent mode corresponds to a state where the DAC maintains a stable output level to ensure that no dynamic
consumption occurs.
3. Guaranteed by characterization results, not tested in production.

Figure 54. 12-bit buffered/non-buffered DAC

Buffered/Non-buffered DAC

Buffer(1)
RL
12-bit DAC_OUTx
digital to
analog
converter

CL

ai17157V2

1. The DAC integrates an output buffer that can be used to reduce the output impedance and to drive external
loads directly, without the use of an external operational amplifier. The buffer can be bypassed by
configuring the BOFFx bit in the DAC_CR register.

6.3.22 Temperature sensor characteristics

Table 68. Temperature sensor characteristics

Symbol Parameter Min Typ Max Unit

TL(1) VSENSE linearity with temperature - ±1 ±2 °C

(1)
Avg_Slope Average slope - 2.5 - mV/°C
V25(1) Voltage at 25 °C - 0.76 - V
tSTART(2) Startup time - 6 10 µs
ADC sampling time when reading the
TS_temp(2) 10 - - µs
temperature (1 °C accuracy)
1. Guaranteed by characterization results, not tested in production.
2. Guaranteed by design, not tested in production.

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STM32F21xxx Electrical characteristics

6.3.23 VBAT monitoring characteristics

Table 69. VBAT monitoring characteristics

Symbol Parameter Min Typ Max Unit

R Resistor bridge for VBAT - 50 - KΩ

Q Ratio on VBAT measurement - 2 -
(1)
Er Error on Q –1 - +1 %
ADC sampling time when reading the VBAT
TS_vbat(2)(2) 5 - - µs
(1 mV accuracy)
1. Guaranteed by design, not tested in production.
2. Shortest sampling time can be determined in the application by multiple iterations.

6.3.24 Embedded reference voltage

The parameters given in Table 70 are derived from tests performed under ambient
temperature and VDD supply voltage conditions summarized in Table 13.

Table 70. Embedded internal reference voltage

Symbol Parameter Conditions Min Typ Max Unit

VREFINT Internal reference voltage –40 °C < TA < +105 °C 1.18 1.21 1.24 V
ADC sampling time when
TS_vrefint(1) reading the internal reference - 10 - - µs
voltage
Internal reference voltage
VRERINT_s
(2) spread over the temperature VDD = 3 V - 3 5 mV
range
TCoeff(2) Temperature coefficient - - 30 50 ppm/°C
(2)
tSTART Startup time - - 6 10 µs
1. Shortest sampling time can be determined in the application by multiple iterations.
2. Guaranteed by design, not tested in production.

6.3.25 FSMC characteristics

Asynchronous waveforms and timings
Figure 55 through Figure 58 represent asynchronous waveforms and Table 71 through
Table 74 provide the corresponding timings. The results shown in these tables are obtained
with the following FSMC configuration:
• AddressSetupTime = 1
• AddressHoldTime = 1
• DataSetupTime = 1
• BusTurnAroundDuration = 0x0
In all timing tables, the THCLK is the HCLK clock period.

DocID17050 Rev 13 131/180

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Electrical characteristics STM32F21xxx

Figure 55. Asynchronous non-multiplexed SRAM/PSRAM/NOR read waveforms

TW.%

&3-#?.%

TV./%?.% T W./% T H.%?./%

&3-#?./%

&3-#?.7%

TV!?.% T H!?./%

&3-#?!;= !DDRESS
TV",?.% T H",?./%

&3-#?.",;=

T H$ATA?.%

T SU$ATA?./% TH$ATA?./%

T SU$ATA?.%

&3-#?$;= $ATA

T V.!$6?.%

TW.!$6

&3-#?.!$6 

AIC

1. Mode 2/B, C and D only. In Mode 1, FSMC_NADV is not used.

Table 71. Asynchronous non-multiplexed SRAM/PSRAM/NOR read timings(1)(2)

Symbol Parameter Min Max Unit

tw(NE) FSMC_NE low time 2THCLK– 0.5 2THCLK+0.5 ns

tv(NOE_NE) FSMC_NEx low to FSMC_NOE low 0.5 2.5 ns
tw(NOE) FSMC_NOE low time 2THCLK- 1 2THCLK+ 0.5 ns
th(NE_NOE) FSMC_NOE high to FSMC_NE high hold time 0 - ns
tv(A_NE) FSMC_NEx low to FSMC_A valid - 4 ns
th(A_NOE) Address hold time after FSMC_NOE high 0 - ns
tv(BL_NE) FSMC_NEx low to FSMC_BL valid - 0.5 ns
th(BL_NOE) FSMC_BL hold time after FSMC_NOE high 0 - ns
tsu(Data_NE) Data to FSMC_NEx high setup time THCLK+ 0.5 - ns
tsu(Data_NOE) Data to FSMC_NOEx high setup time THCLK+ 2.5 - ns
th(Data_NOE) Data hold time after FSMC_NOE high 0 - ns
th(Data_NE) Data hold time after FSMC_NEx high 0 - ns
tv(NADV_NE) FSMC_NEx low to FSMC_NADV low - 2.5 ns
tw(NADV) FSMC_NADV low time - THCLK– 0.5 ns
1. CL = 30 pF.
2. Guaranteed by characterization results, not tested in production.

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STM32F21xxx Electrical characteristics

Figure 56. Asynchronous non-multiplexed SRAM/PSRAM/NOR write waveforms

WZ1(

)60&B1([

)60&B12(
WY1:(B1( WZ1:( W K1(B1:(

)60&B1:(

WY$B1( WK$B1:(

)60&B$>@ $GGUHVV
WY%/B1( WK%/B1:(

)60&B1%/>@ 1%/
WY'DWDB1( WK'DWDB1:(

)60&B'>@ 'DWD
W Y1$'9B1(
WZ1$'9
)60&B1$'9

DL

1. Mode 2/B, C and D only. In Mode 1, FSMC_NADV is not used.

Table 72. Asynchronous non-multiplexed SRAM/PSRAM/NOR write timings(1)(2)

Symbol Parameter Min Max Unit

tw(NE) FSMC_NE low time 3THCLK 3THCLK+ 4 ns

tv(NWE_NE) FSMC_NEx low to FSMC_NWE low THCLK– 0.5 THCLK+ 0.5 ns
tw(NWE) FSMC_NWE low time THCLK– 0.5 THCLK+ 3 ns
FSMC_NWE high to FSMC_NE high hold
th(NE_NWE) THCLK - ns
time
tv(A_NE) FSMC_NEx low to FSMC_A valid - 0 ns
th(A_NWE) Address hold time after FSMC_NWE high THCLK- 3 - ns
tv(BL_NE) FSMC_NEx low to FSMC_BL valid - 0.5 ns
FSMC_BL hold time after FSMC_NWE
th(BL_NWE) THCLK– 1 - ns
high
tv(Data_NE) Data to FSMC_NEx low to Data valid - THCLK+ 5 ns
th(Data_NWE) Data hold time after FSMC_NWE high THCLK+0.5 - ns
tv(NADV_NE) FSMC_NEx low to FSMC_NADV low - 2 ns
tw(NADV) FSMC_NADV low time - THCLK+ 1.5 ns
1. CL = 30 pF.
2. Guaranteed by characterization results, not tested in production.

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179
Electrical characteristics STM32F21xxx

Figure 57. Asynchronous multiplexed PSRAM/NOR read waveforms

TW.%

&3-#?.%

TV./%?.% T H.%?./%

&3-#?./%

T W./%

&3-#?.7%

TV!?.% T H!?./%

&3-#?!;= !DDRESS
TV",?.% TH",?./%

&3-#?.",;= .",

TH$ATA?.%

TSU$ATA?.%

T V!?.% TSU$ATA?./% TH$ATA?./%

&3-#? !$;= !DDRESS $ATA

T V.!$6?.% TH!$?.!$6
TW.!$6

&3-#?.!$6

AIB

Table 73. Asynchronous multiplexed PSRAM/NOR read timings(1)(2)

Symbol Parameter Min Max Unit

tw(NE) FSMC_NE low time 3THCLK-1 3THCLK+1 ns

tv(NOE_NE) FSMC_NEx low to FSMC_NOE low 2THCLK 2THCLK+0.5 ns
tw(NOE) FSMC_NOE low time THCLK-1 THCLK+1 ns
th(NE_NOE) FSMC_NOE high to FSMC_NE high hold time 0 - ns
tv(A_NE) FSMC_NEx low to FSMC_A valid - 2 ns
tv(NADV_NE) FSMC_NEx low to FSMC_NADV low 1 2.5 ns
tw(NADV) FSMC_NADV low time THCLK– 1.5 THCLK ns
FSMC_AD(adress) valid hold time after
th(AD_NADV) THCLK - ns
FSMC_NADV high)
th(A_NOE) Address hold time after FSMC_NOE high THCLK - ns
th(BL_NOE) FSMC_BL time after FSMC_NOE high 0 - ns
tv(BL_NE) FSMC_NEx low to FSMC_BL valid - 1 ns
tsu(Data_NE) Data to FSMC_NEx high setup time THCLK+ 2 - ns
tsu(Data_NOE) Data to FSMC_NOE high setup time THCLK+ 3 - ns

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STM32F21xxx Electrical characteristics

Table 73. Asynchronous multiplexed PSRAM/NOR read timings(1)(2) (continued)

Symbol Parameter Min Max Unit

th(Data_NE) Data hold time after FSMC_NEx high 0 - ns

th(Data_NOE) Data hold time after FSMC_NOE high 0 - ns
1. CL = 30 pF.
2. Guaranteed by characterization results, not tested in production.

Figure 58. Asynchronous multiplexed PSRAM/NOR write waveforms

WZ1(

)60&B1([

)60&B12(
WY1:(B1( WZ1:( W K1(B1:(

)60&B1:(

WY$B1( WK$B1:(

)60&B$>@ $GGUHVV
WY%/B1( WK%/B1:(

)60&B1%/>@ 1%/
W Y$B1( W Y'DWDB1$'9 WK'DWDB1:(

)60&B$'>@ $GGUHVV 'DWD

W Y1$'9B1( WK$'B1$'9
WZ1$'9

)60&B1$'9

DL%

Table 74. Asynchronous multiplexed PSRAM/NOR write timings(1)(2)

Symbol Parameter Min Max Unit

tw(NE) FSMC_NE low time 4THCLK-1 4THCLK+1 ns

tv(NWE_NE) FSMC_NEx low to FSMC_NWE low THCLK- 1 THCLK ns
tw(NWE) FSMC_NWE low tim e 2THCLK 2THCLK+1 ns
th(NE_NWE) FSMC_NWE high to FSMC_NE high hold time THCLK- 1 - ns
tv(A_NE) FSMC_NEx low to FSMC_A valid - 0 ns
tv(NADV_NE) FSMC_NEx low to FSMC_NADV low 1 2 ns
tw(NADV) FSMC_NADV low time THCLK– 2 THCLK+ 2 ns
FSMC_AD(adress) valid hold time after
th(AD_NADV) THCLK - ns
FSMC_NADV high)

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Electrical characteristics STM32F21xxx

Table 74. Asynchronous multiplexed PSRAM/NOR write timings(1)(2) (continued)

Symbol Parameter Min Max Unit

th(A_NWE) Address hold time after FSMC_NWE high THCLK– 0.5 - ns

th(BL_NWE) FSMC_BL hold time after FSMC_NWE high THCLK- 1 - ns
tv(BL_NE) FSMC_NEx low to FSMC_BL valid - 0.5 ns
tv(Data_NADV) FSMC_NADV high to Data valid - THCLK+2 ns
th(Data_NWE) Data hold time after FSMC_NWE high THCLK– 0.5 - ns
1. CL = 30 pF.
2. Guaranteed by characterization results, not tested in production.

Synchronous waveforms and timings

Figure 59 through Figure 62 represent synchronous waveforms, and Table 76 through
Table 78 provide the corresponding timings. The results shown in these tables are obtained
with the following FSMC configuration:
• BurstAccessMode = FSMC_BurstAccessMode_Enable;
• MemoryType = FSMC_MemoryType_CRAM;
• WriteBurst = FSMC_WriteBurst_Enable;
• CLKDivision = 1; (0 is not supported, see the STM32F20xxx/21xxx reference manual)
• DataLatency = 1 for NOR Flash; DataLatency = 0 for PSRAM
In all timing tables, the THCLK is the HCLK clock period.

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Figure 59. Synchronous multiplexed NOR/PSRAM read timings

WZ&/. WZ&/. %867851 

)60&B&/.

'DWDODWHQF\ 
WG&/./1([/ W G&/./1([+

)60&B1([

WG&/./1$'9/ WG&/./1$'9+

)60&B1$'9

WG&/./$9 WG&/./$,9

)60&B$>@

WG&/.+12(/ WG&/./12(+

)60&B12(

WG&/./$',9 WK&/.+$'9
WG&/./$'9 WVX$'9&/.+ WVX$'9&/.+ WK&/.+$'9

)60&B$'>@ $'>@ ' '

WVX1:$,79&/.+ WK&/.+1:$,79

)60&B1:$,7
:$,7&)* E:$,732/E WVX1:$,79&/.+ WK&/.+1:$,79

)60&B1:$,7
:$,7&)* E:$,732/E
WVX1:$,79&/.+ WK&/.+1:$,79

DLK

Table 75. Synchronous multiplexed NOR/PSRAM read timings(1)(2)

Symbol Parameter Min Max Unit

tw(CLK) FSMC_CLK period 2THCLK - ns

td(CLKL-NExL) FSMC_CLK low to FSMC_NEx low (x=0..2) - 0 ns
td(CLKL-NExH) FSMC_CLK low to FSMC_NEx high (x= 0…2) 1 - ns
td(CLKL-NADVL) FSMC_CLK low to FSMC_NADV low - 1.5 ns
td(CLKL-NADVH) FSMC_CLK low to FSMC_NADV high 2.5 - ns
td(CLKL-AV) FSMC_CLK low to FSMC_Ax valid (x=16…25) - 0 ns
td(CLKL-AIV) FSMC_CLK low to FSMC_Ax invalid (x=16…25) 0 - ns
td(CLKH-NOEL) FSMC_CLK high to FSMC_NOE low - 1 ns
td(CLKL-NOEH) FSMC_CLK low to FSMC_NOE high 1 - ns
td(CLKL-ADV) FSMC_CLK low to FSMC_AD[15:0] valid - 3 ns
td(CLKL-ADIV) FSMC_CLK low to FSMC_AD[15:0] invalid 0 - ns

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Electrical characteristics STM32F21xxx

Table 75. Synchronous multiplexed NOR/PSRAM read timings(1)(2) (continued)

Symbol Parameter Min Max Unit

tsu(ADV-CLKH) FSMC_A/D[15:0] valid data before FSMC_CLK high 5 - ns

th(CLKH-ADV) FSMC_A/D[15:0] valid data after FSMC_CLK high 0 - ns
1. CL = 30 pF.
2. Guaranteed by characterization results, not tested in production.

Figure 60. Synchronous multiplexed PSRAM write timings

TW#,+ TW#,+ "53452.

&3-#?#,+

$ATALATENCY
TD#,+, .%X, TD#,+, .%X(

&3-#?.%X

TD#,+, .!$6, TD#,+, .!$6(

&3-#?.!$6

TD#,+, !6 TD#,+, !)6

&3-#?!;=

TD#,+, .7%, TD#,+, .7%(

&3-#?.7%

TD#,+, !$)6 TD#,+, $ATA

TD#,+, !$6 TD#,+, $ATA

&3-#?!$;= !$;= $ $

&3-#?.7!)4
7!)4#&'B7!)40/,B TSU.7!)46 #,+( TH#,+( .7!)46

TD#,+, .",(

&3-#?.",

AIG

Table 76. Synchronous multiplexed PSRAM write timings(1)(2)

Symbol Parameter Min Max Unit

tw(CLK) FSMC_CLK period 2THCLK- 1 - ns

td(CLKL-NExL) FSMC_CLK low to FSMC_NEx low (x=0..2) - 0 ns
td(CLKL-NExH) FSMC_CLK low to FSMC_NEx high (x= 0…2) 2 - ns
td(CLKL-NADVL) FSMC_CLK low to FSMC_NADV low - 2 ns
td(CLKL-NADVH) FSMC_CLK low to FSMC_NADV high 3 - ns
td(CLKL-AV) FSMC_CLK low to FSMC_Ax valid (x=16…25) - 0 ns
td(CLKL-AIV) FSMC_CLK low to FSMC_Ax invalid (x=16…25) 7 - ns

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STM32F21xxx Electrical characteristics

Table 76. Synchronous multiplexed PSRAM write timings(1)(2) (continued)

Symbol Parameter Min Max Unit

td(CLKL-NWEL) FSMC_CLK low to FSMC_NWE low - 1 ns

td(CLKL-NWEH) FSMC_CLK low to FSMC_NWE high 0 - ns
td(CLKL-ADIV) FSMC_CLK low to FSMC_AD[15:0] invalid 0 - ns
td(CLKL-DATA) FSMC_A/D[15:0] valid data after FSMC_CLK low - 2 ns
td(CLKL-NBLH) FSMC_CLK low to FSMC_NBL high 0.5 - ns
1. CL = 30 pF.
2. Guaranteed by characterization results, not tested in production.

Figure 61. Synchronous non-multiplexed NOR/PSRAM read timings

TW#,+ TW#,+ "53452.

&3-#?#,+

TD#,+, .%X, TD#,+, .%X(

$ATALATENCY
&3-#?.%X

TD#,+, .!$6, TD#,+, .!$6(

&3-#?.!$6

TD#,+, !6 TD#,+, !)6

&3-#?!;=

TD#,+( ./%, TD#,+, ./%(

&3-#?./%
TSU$6 #,+( TH#,+( $6
TSU$6 #,+( TH#,+( $6

&3-#?$;= $ $ $

TSU.7!)46 #,+( TH#,+( .7!)46

&3-#?.7!)4
7!)4#&'B7!)40/,B
TSU.7!)46 #,+( T H#,+( .7!)46

&3-#?.7!)4
7!)4#&'B7!)40/,B
TSU.7!)46 #,+( TH#,+( .7!)46

AIG

Table 77. Synchronous non-multiplexed NOR/PSRAM read timings(1)(2)

Symbol Parameter Min Max Unit

tw(CLK) FSMC_CLK period 2THCLK - ns

td(CLKL-NExL) FSMC_CLK low to FSMC_NEx low (x=0..2) - 0 ns
td(CLKL-NExH) FSMC_CLK low to FSMC_NEx high (x= 0…2) 1 - ns
td(CLKL-NADVL) FSMC_CLK low to FSMC_NADV low - 2.5 ns

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Electrical characteristics STM32F21xxx

Table 77. Synchronous non-multiplexed NOR/PSRAM read timings(1)(2) (continued)

Symbol Parameter Min Max Unit

td(CLKL-NADVH) FSMC_CLK low to FSMC_NADV high 4 - ns

td(CLKL-AV) FSMC_CLK low to FSMC_Ax valid (x=16…25) - 0 ns
td(CLKL-AIV) FSMC_CLK low to FSMC_Ax invalid (x=16…25) 3 - ns
td(CLKH-NOEL) FSMC_CLK high to FSMC_NOE low - 1 ns
td(CLKL-NOEH) FSMC_CLK low to FSMC_NOE high 1.5 - ns
tsu(DV-CLKH) FSMC_D[15:0] valid data before FSMC_CLK high 8 - ns
th(CLKH-DV) FSMC_D[15:0] valid data after FSMC_CLK high 0 - ns
1. CL = 30 pF.
2. Guaranteed by characterization results, not tested in production.

Figure 62. Synchronous non-multiplexed PSRAM write timings

TW#,+ TW#,+ "53452.

&3-#?#,+

TD#,+, .%X, TD#,+, .%X(

$ATALATENCY
&3-#?.%X

TD#,+, .!$6, TD#,+, .!$6(

&3-#?.!$6

TD#,+, !6 TD#,+, !)6

&3-#?!;=

TD#,+, .7%, TD#,+, .7%(

&3-#?.7%

TD#,+, $ATA TD#,+, $ATA

&3-#?$;= $ $

&3-#?.7!)4
7!)4#&'B7!)40/,B TSU.7!)46 #,+( TD#,+, .",(

TH#,+( .7!)46

&3-#?.",

AIG

Table 78. Synchronous non-multiplexed PSRAM write timings(1)(2)

Symbol Parameter Min Max Unit

tw(CLK) FSMC_CLK period 2THCLK- 1 - ns

td(CLKL-NExL) FSMC_CLK low to FSMC_NEx low (x=0..2) - 1 ns
td(CLKL-NExH) FSMC_CLK low to FSMC_NEx high (x= 0…2) 1 - ns

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STM32F21xxx Electrical characteristics

Table 78. Synchronous non-multiplexed PSRAM write timings(1)(2) (continued)

Symbol Parameter Min Max Unit

td(CLKL-
FSMC_CLK low to FSMC_NADV low - 5 ns
NADVL)

td(CLKL-
FSMC_CLK low to FSMC_NADV high 6 - ns
NADVH)

td(CLKL-AV) FSMC_CLK low to FSMC_Ax valid (x=16…25) - 0 ns

td(CLKL-AIV) FSMC_CLK low to FSMC_Ax invalid (x=16…25) 8 - ns
td(CLKL-NWEL) FSMC_CLK low to FSMC_NWE low - 1 ns
td(CLKL-NWEH) FSMC_CLK low to FSMC_NWE high 1 - ns
td(CLKL-Data) FSMC_D[15:0] valid data after FSMC_CLK low - 2 ns
td(CLKL-NBLH) FSMC_CLK low to FSMC_NBL high 2 - ns
1. CL = 30 pF.
2. Guaranteed by characterization results, not tested in production.

PC Card/CompactFlash controller waveforms and timings

Figure 63 through Figure 68 represent synchronous waveforms, with Table 79 and Table 80
providing the corresponding timings. The results shown in these table are obtained with the
following FSMC configuration:
• COM.FSMC_SetupTime = 0x04;
• COM.FSMC_WaitSetupTime = 0x07;
• COM.FSMC_HoldSetupTime = 0x04;
• COM.FSMC_HiZSetupTime = 0x00;
• ATT.FSMC_SetupTime = 0x04;
• ATT.FSMC_WaitSetupTime = 0x07;
• ATT.FSMC_HoldSetupTime = 0x04;
• ATT.FSMC_HiZSetupTime = 0x00;
• IO.FSMC_SetupTime = 0x04;
• IO.FSMC_WaitSetupTime = 0x07;
• IO.FSMC_HoldSetupTime = 0x04;
• IO.FSMC_HiZSetupTime = 0x00;
• TCLRSetupTime = 0;
• TARSetupTime = 0;
In all timing tables, the THCLK is the HCLK clock period.

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Electrical characteristics STM32F21xxx

Figure 63. PC Card/CompactFlash controller waveforms for common memory read

access

)60&B1&(B
)60&B1&(B

WY1&([$ WK1&([$,

)60&B$>@

WK1&([15(*
WG15(*1&([
WK1&([1,25'
WG1,25'1&([
WK1&([1,2:5
)60&B15(*
)60&B1,2:5
)60&B1,25'

)60&B1:(

WG1&(B12( WZ12(
)60&B12(

WVX'12( WK12('

)60&B'>@

DLE

1. FSMC_NCE4_2 remains high (inactive during 8-bit access.

Figure 64. PC Card/CompactFlash controller waveforms for common memory write

access

)60&B1&(B

)60&B1&(B +LJK

WY1&(B$ WK1&(B$,
)60&B$>@

WK1&(B15(*
WG15(*1&(B
WK1&(B1,25'
WG1,25'1&(B
WK1&(B1,2:5
)60&B15(*
)60&B1,2:5
)60&B1,25'
WG1&(B1:( WZ1:( WG1:(1&(B
)60&B1:(

)60&B12(
0(0[+,= 
WG'1:(
WY1:(' WK1:('

)60&B'>@

DLE

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STM32F21xxx Electrical characteristics

Figure 65. PC Card/CompactFlash controller waveforms for attribute memory read

access

)60&B1&(B

WY1&(B$ WK1&(B$,
)60&B1&(B +LJK

)60&B$>@

)60&B1,2:5
)60&B1,25'
WG15(*1&(B WK1&(B15(*

)60&B15(*

)60&B1:(

WG1&(B12( WZ12( WG12(1&(B

)60&B12(

WVX'12( WK12('

)60&B'>@

DLE

1. Only data bits 0...7 are read (bits 8...15 are disregarded).

DocID17050 Rev 13 143/180

179
Electrical characteristics STM32F21xxx

Figure 66. PC Card/CompactFlash controller waveforms for attribute memory write

access

)60&B1&(B

)60&B1&(B +LJK

WY1&(B$ WK1&(B$,

)60&B$>@

)60&B1,2:5
)60&B1,25'
WG15(*1&(B WK1&(B15(*

)60&B15(*
WG1&(B1:( WZ1:(

)60&B1:(
WG1:(1&(B

)60&B12(

WY1:('

)60&B'>@

DLE

1. Only data bits 0...7 are driven (bits 8...15 remains Hi-Z).

Figure 67. PC Card/CompactFlash controller waveforms for I/O space read access
)60&B1&(B
)60&B1&(B
WY1&([$ WK1&(B$,

)60&B$>@

)60&B15(*
)60&B1:(
)60&B12(

)60&B1,2:5
WG1,25'1&(B WZ1,25'

)60&B1,25'

WVX'1,25' WG1,25''

)60&B'>@

DL%

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STM32F21xxx Electrical characteristics

Figure 68. PC Card/CompactFlash controller waveforms for I/O space write access

)60&B1&(B
)60&B1&(B
WY1&([$ WK1&(B$,

)60&B$>@

)60&B15(*
)60&B1:(
)60&B12(

)60&B1,25'
WG1&(B1,2:5 WZ1,2:5

)60&B1,2:5
$77[+,= 
WK1,2:5'
WY1,2:5'

)60&B'>@

DLF

Table 79. Switching characteristics for PC Card/CF read and write cycles in
attribute/common space(1)(2)
Symbol Parameter Min Max Unit

tv(NCEx-A) FSMC_Ncex low to FSMC_Ay valid - 0 ns

th(NCEx_AI) FSMC_NCEx high to FSMC_Ax invalid 4 - ns
td(NREG-NCEx) FSMC_NCEx low to FSMC_NREG valid - 3.5 ns
th(NCEx-NREG) FSMC_NCEx high to FSMC_NREG invalid THCLK+ 4 - ns
td(NCEx-NWE) FSMC_NCEx low to FSMC_NWE low - 5THCLK+ 1 ns
td(NCEx-NOE) FSMC_NCEx low to FSMC_NOE low - 5THCLK ns
tw(NOE) FSMC_NOE low width 8THCLK– 0.5 8THCLK+ 1 ns
td(NOE_NCEx) FSMC_NOE high to FSMC_NCEx high 5THCLK+ 2.5 - ns
tsu (D-NOE) FSMC_D[15:0] valid data before FSMC_NOE high 4 - ns
th (N0E-D) FSMC_N0E high to FSMC_D[15:0] invalid 2 - ns
tw(NWE) FSMC_NWE low width 8THCLK- 1 8THCLK+ 4 ns
td(NWE_NCEx) FSMC_NWE high to FSMC_NCEx high 5THCLK+ 1.5 - ns
td(NCEx-NWE) FSMC_NCEx low to FSMC_NWE low - 5HCLK+ 1 ns
tv (NWE-D) FSMC_NWE low to FSMC_D[15:0] valid - 0 ns
th (NWE-D) FSMC_NWE high to FSMC_D[15:0] invalid 8THCLK - ns
td (D-NWE) FSMC_D[15:0] valid before FSMC_NWE high 13THCLK - ns
1. CL = 30 pF.
2. Guaranteed by characterization results, not tested in production.

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Electrical characteristics STM32F21xxx

Table 80. Switching characteristics for PC Card/CF read and write cycles in I/O space(1)(2)
Symbol Parameter Min Max Unit

tw(NIOWR) FSMC_NIOWR low width 8THCLK - 0.5 - ns

tv(NIOWR-D) FSMC_NIOWR low to FSMC_D[15:0] valid - 5THCLK- 1 ns
th(NIOWR-D) FSMC_NIOWR high to FSMC_D[15:0] invalid 8THCLK- 3 - ns
td(NCE4_1-NIOWR) FSMC_NCE4_1 low to FSMC_NIOWR valid - 5THCLK+ 1.5 ns
th(NCEx-NIOWR) FSMC_NCEx high to FSMC_NIOWR invalid 5THCLK - ns
td(NIORD-NCEx) FSMC_NCEx low to FSMC_NIORD valid - 5THCLK+ 1 ns
th(NCEx-NIORD) FSMC_NCEx high to FSMC_NIORD) valid 5THCLK– 0.5 - ns
tw(NIORD) FSMC_NIORD low width 8THCLK+ 1 - ns
tsu(D-NIORD) FSMC_D[15:0] valid before FSMC_NIORD high 9.5 - ns
td(NIORD-D) FSMC_D[15:0] valid after FSMC_NIORD high 0 - ns
1. CL = 30 pF.
2. Guaranteed by characterization results, not tested in production.

NAND controller waveforms and timings

Figure 69 through Figure 72 represent synchronous waveforms, together with Table 81 and
Table 82 provides the corresponding timings. The results shown in this table are obtained
with the following FSMC configuration:
• COM.FSMC_SetupTime = 0x01;
• COM.FSMC_WaitSetupTime = 0x03;
• COM.FSMC_HoldSetupTime = 0x02;
• COM.FSMC_HiZSetupTime = 0x01;
• ATT.FSMC_SetupTime = 0x01;
• ATT.FSMC_WaitSetupTime = 0x03;
• ATT.FSMC_HoldSetupTime = 0x02;
• ATT.FSMC_HiZSetupTime = 0x01;
• Bank = FSMC_Bank_NAND;
• MemoryDataWidth = FSMC_MemoryDataWidth_16b;
• ECC = FSMC_ECC_Enable;
• ECCPageSize = FSMC_ECCPageSize_512Bytes;
• TCLRSetupTime = 0;
• TARSetupTime = 0;
In all timing tables, the THCLK is the HCLK clock period.

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STM32F21xxx Electrical characteristics

Figure 69. NAND controller waveforms for read access

&3-#?.#%X

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Figure 70. NAND controller waveforms for write access

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WY1:(' WK1:('

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AIC

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179
Electrical characteristics STM32F21xxx

Figure 71. NAND controller waveforms for common memory read access

)60&B1&([

$/()60&B$
&/()60&B$
WG$/(12( WK12($/(

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)60&B12(

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Figure 72. NAND controller waveforms for common memory write access

)60&B1&([

$/()60&B$
&/()60&B$
WG$/(12( WZ1:( WK12($/(

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)60&B12(

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)60&B'>@

DLF

Table 81. Switching characteristics for NAND Flash read cycles(1)(2)

Symbol Parameter Min Max Unit

tw(N0E) FSMC_NOE low width 4THCLK- 1 4THCLK+ 2 ns

tsu(D-NOE) FSMC_D[15-0] valid data before FSMC_NOE high 9 - ns
th(NOE-D) FSMC_D[15-0] valid data after FSMC_NOE high 3 - ns
td(ALE-NOE) FSMC_ALE valid before FSMC_NOE low - 3THCLK ns
th(NOE-ALE) FSMC_NWE high to FSMC_ALE invalid 3THCLK+ 2 - ns
1. CL = 30 pF.
2. Guaranteed by characterization results, not tested in production.

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STM32F21xxx Electrical characteristics

Table 82. Switching characteristics for NAND Flash write cycles(1)(2)

Symbol Parameter Min Max Unit

tw(NWE) FSMC_NWE low width 4THCLK- 1 4THCLK+ 3 ns

tv(NWE-D) FSMC_NWE low to FSMC_D[15-0] valid - 0 ns
th(NWE-D) FSMC_NWE high to FSMC_D[15-0] invalid 3THCLK - ns
td(D-NWE) FSMC_D[15-0] valid before FSMC_NWE high 5THCLK - ns
td(ALE-NWE) FSMC_ALE valid before FSMC_NWE low - 3THCLK+ 2 ns
th(NWE-ALE) FSMC_NWE high to FSMC_ALE invalid 3THCLK- 2 - ns
1. CL = 30 pF.
2. Guaranteed by characterization results, not tested in production.

6.3.26 Camera interface (DCMI) timing specifications

Table 83. DCMI characteristics

Symbol Parameter Conditions Min Max

- Frequency ratio DCMI_PIXCLK/fHCLK DCMI_PIXCLK= 48 MHz - 0.4

6.3.27 SD/SDIO MMC card host interface (SDIO) characteristics

Unless otherwise specified, the parameters given in Table 84 are derived from tests
performed under ambient temperature, fPCLKx frequency and VDD supply voltage conditions
summarized in Table 13.
Refer to Section 6.3.16: I/O port characteristics for more details on the input/output alternate
function characteristics (D[7:0], CMD, CK).

Figure 73. SDIO high-speed mode

TF TR

T#
T7#+( T7#+,

#+

T/6 T/(
$#-$
OUTPUT

T)35 T)(

$#-$
INPUT
AI

DocID17050 Rev 13 149/180

179
Electrical characteristics STM32F21xxx

Figure 74. SD default mode

#+
T/6$ T/($
$#-$
OUTPUT

AI

Table 84. SD/MMC characteristics

Symbol Parameter Conditions Min Max Unit

Clock frequency in data transfer

fPP CL ≤ 30 pF 0 48 MHz
mode
- SDIO_CK/fPCLK2 frequency ratio - - 8/3 -
tW(CKL) Clock low time, fPP = 16 MHz CL ≤ 30 pF 32 -
tW(CKH) Clock high time, fPP = 16 MHz CL ≤ 30 pF 31 -
ns
tr Clock rise time CL ≤ 30 pF - 3.5
tf Clock fall time CL ≤ 30 pF - 5
CMD, D inputs (referenced to CK)
tISU Input setup time CL ≤ 30 pF 2 -
ns
tIH Input hold time CL ≤ 30 pF 0 -
CMD, D outputs (referenced to CK) in MMC and SD HS mode
tOV Output valid time CL ≤ 30 pF - 6
ns
tOH Output hold time CL ≤ 30 pF 0.3 -

CMD, D outputs (referenced to CK) in SD default mode(1)

tOVD Output valid default time CL ≤ 30 pF - 7
ns
tOHD Output hold default time CL ≤ 30 pF 0.5 -
1. Refer to SDIO_CLKCR, the SDI clock control register to control the CK output.

6.3.28 RTC characteristics

Table 85. RTC characteristics

Symbol Parameter Conditions Min Max

Any read/write operation

- fPCLK1/RTCCLK frequency ratio 4 -
from/to an RTC register

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STM32F21xxx Package information

7 Package information

In order to meet environmental requirements, ST offers these devices in different grades of

ECOPACK® packages, depending on their level of environmental compliance. ECOPACK®
specifications, grade definitions and product status are available at: www.st.com.
ECOPACK® is an ST trademark.

7.1 LQFP64 package information

Figure 75. LQFP64 - 64-pin, 10 x 10 mm low-profile quad flat package outline

6($7,1*3/$1(
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FFF &

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1. Drawing is not to scale.

Table 86. LQFP64 - 64-pin, 10 x 10 mm low-profile quad flat

package mechanical data
millimeters inches(1)
Symbol
Min Typ Max Min Typ Max

A - - 1.600 - - 0.0630
A1 0.050 - 0.150 0.0020 - 0.0059
A2 1.350 1.400 1.450 0.0531 0.0551 0.0571
b 0.170 0.220 0.270 0.0067 0.0087 0.0106

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Package information STM32F21xxx

Table 86. LQFP64 - 64-pin, 10 x 10 mm low-profile quad flat

package mechanical data (continued)
millimeters inches(1)
Symbol
Min Typ Max Min Typ Max

c 0.090 - 0.200 0.0035 - 0.0079

D - 12.000 - - 0.4724 -
D1 - 10.000 - - 0.3937 -
D3 - 7.500 - - 0.2953 -
E - 12.000 - - 0.4724 -
E1 - 10.000 - - 0.3937 -
E3 - 7.500 - - 0.2953 -
e - 0.500 - - 0.0197 -
K 0° 3.5° 7° 0° 3.5° 7°
L 0.450 0.600 0.750 0.0177 0.0236 0.0295
L1 - 1.000 - - 0.0394 -
ccc - - 0.080 - - 0.0031
1. Values in inches are converted from mm and rounded to 4 decimal digits.

Figure 76. LQFP64 - 64-pin, 10 x 10 mm low-profile quad flat package

recommended footprint

 


  






 


 





AIC

1. Dimensions are expressed in millimeters.

152/180 DocID17050 Rev 13

STM32F21xxx Package information

7.2 LQFP100 package information

Figure 77. LQFP100 - 100-pin, 14 x 14 mm low-profile quad flat package outline

3%!4).'0,!.%
#

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!

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1. Drawing is not to scale.

Table 87. LQPF100 - 100-pin, 14 x 14 mm low-profile quad flat package

mechanical data
millimeters inches(1)
Symbol
Min Typ Max Min Typ Max

A - - 1.600 - - 0.0630
A1 0.050 - 0.150 0.0020 - 0.0059
A2 1.350 1.400 1.450 0.0531 0.0551 0.0571
b 0.170 0.220 0.270 0.0067 0.0087 0.0106
c 0.090 - 0.200 0.0035 - 0.0079
D 15.800 16.000 16.200 0.6220 0.6299 0.6378
D1 13.800 14.000 14.200 0.5433 0.5512 0.5591

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Package information STM32F21xxx

Table 87. LQPF100 - 100-pin, 14 x 14 mm low-profile quad flat package

mechanical data (continued)
millimeters inches(1)
Symbol
Min Typ Max Min Typ Max

D3 - 12.000 - - 0.4724 -
E 15.800 16.000 16.200 0.6220 0.6299 0.6378
E1 13.800 14.000 14.200 0.5433 0.5512 0.5591
E3 - 12.000 - - 0.4724 -
e - 0.500 - - 0.0197 -
L 0.450 0.600 0.750 0.0177 0.0236 0.0295
L1 - 1.000 - - 0.0394 -
k 0.0° 3.5° 7.0° 0.0° 3.5° 7.0°
ccc - - 0.080 - - 0.0031
1. Values in inches are converted from mm and rounded to 4 decimal digits.

Figure 78. LQFP100 - 100-pin, 14 x 14 mm low-profile quad flat

recommended footprint
 

 




 

 


 





AIC

1. Dimensions are expressed in millimeters.

154/180 DocID17050 Rev 13

STM32F21xxx Package information

Device marking
Figure 79 gives an example of topside marking orientation versus Pin 1 identifier location.

Figure 79. LQFP100 marking (package top view)

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670)

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1. Parts marked as “ES”, “E” or accompanied by an Engineering Sample notification letter, are not yet
qualified and therefore not yet ready to be used in production and any consequences deriving from such
usage will not be at ST charge. In no event, ST will be liable for any customer usage of these engineering
samples in production. ST Quality has to be contacted prior to any decision to use these Engineering
samples to run qualification activity.

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179
Package information STM32F21xxx

7.3 LQFP144 package information

Figure 80. LQFP144 - 144-pin, 20 x 20 mm low-profile quad flat package outline
6($7,1*
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1. Drawing is not to scale.

156/180 DocID17050 Rev 13

STM32F21xxx Package information

Table 88. LQFP144 - 144-pin, 20 x 20 mm low-profile quad flat package

mechanical data
millimeters inches(1)
Symbol
Min Typ Max Min Typ Max

A - - 1.600 - - 0.0630
A1 0.050 - 0.150 0.0020 - 0.0059
A2 1.350 1.400 1.450 0.0531 0.0551 0.0571
b 0.170 0.220 0.270 0.0067 0.0087 0.0106
c 0.090 - 0.200 0.0035 - 0.0079
D 21.800 22.000 22.200 0.8583 0.8661 0.8740
D1 19.800 20.000 20.200 0.7795 0.7874 0.7953
D3 - 17.500 - - 0.6890 -
E 21.800 22.000 22.200 0.8583 0.8661 0.8740
E1 19.800 20.000 20.200 0.7795 0.7874 0.7953
E3 - 17.500 - - 0.6890 -
e - 0.500 - - 0.0197 -
L 0.450 0.600 0.750 0.0177 0.0236 0.0295
L1 - 1.000 - - 0.0394 -
k 0° 3.5° 7° 0° 3.5° 7°
ccc - - 0.080 - - 0.0031
1. Values in inches are converted from mm and rounded to 4 decimal digits.

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179
Package information STM32F21xxx

Figure 81. LQFP144 - 144-pin,20 x 20 mm low-profile quad flat package

recommended footprint


 

  



 


 

 



DLH

1. Dimensions are expressed in millimeters.

158/180 DocID17050 Rev 13

STM32F21xxx Package information

Device marking
Figure 82 gives an example of topside marking orientation versus Pin 1 identifier location.

Figure 82. LQFP144 marking (package top view)

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670)=*7

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1. Parts marked as “ES”, “E” or accompanied by an Engineering Sample notification letter, are not yet
qualified and therefore not yet ready to be used in production and any consequences deriving from such
usage will not be at ST charge. In no event, ST will be liable for any customer usage of these engineering
samples in production. ST Quality has to be contacted prior to any decision to use these Engineering
samples to run qualification activity.

DocID17050 Rev 13 159/180

179
Package information STM32F21xxx

7.4 LQFP176 package information

Figure 83. LQFP176 - 176-pin, 24 x 24 mm low profile quad flat package outline

# 3EATINGPLANE

C
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MM
GAUGEPLANE

K
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,

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0). $
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4?-%?6

1. Drawing is not to scale.

Table 89. LQFP176 - 176-pin, 24 x 24 mm low profile quad flat package

mechanical data
Dimensions

Symbol millimeters inches(1)

Min Typ Max Min Typ Max

A - - 1.600 - - 0.0630
A1 0.050 - 0.150 0.0020 - 0.0059
A2 1.350 - 1.450 0.0531 - 0.0571
b 0.170 - 0.270 0.0067 - 0.0106
c 0.090 - 0.200 0.0035 - 0.0079
D 23.900 - 24.100 0.9409 - 0.9488

160/180 DocID17050 Rev 13

STM32F21xxx Package information

Table 89. LQFP176 - 176-pin, 24 x 24 mm low profile quad flat package

mechanical data (continued)
Dimensions

Symbol millimeters inches(1)

Min Typ Max Min Typ Max

HD 25.900 - 26.100 1.0197 - 1.0276

ZD - 1.250 - - 0.0492 -
E 23.900 - 24.100 0.9409 - 0.9488
HE 25.900 - 26.100 1.0197 - 1.0276
ZE - 1.250 - - 0.0492 -
e - 0.500 - - 0.0197 -
(2)
L 0.450 - 0.750 0.0177 - 0.0295
L1 - 1.000 - - 0.0394 -
k 0° - 7° 0° - 7°
ccc - - 0.080 - - 0.0031
1. Values in inches are converted from mm and rounded to 4 decimal digits.
2. L dimension is measured at gauge plane at 0.25 mm above the seating plane.

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179
Package information STM32F21xxx

Figure 84. LQFP176 - 176-pin, 24 x 24 mm low profile quad flat package

recommended footprint


 
  






 
 






4?&0?6

1. Dimensions are expressed in millimeters.

162/180 DocID17050 Rev 13

STM32F21xxx Package information

7.5 UFBGA176+25 package information

Figure 85. UFBGA176+25 - 201-ball, 10 x 10 mm, 0.65 mm pitch,
ultra fine pitch ball grid array package outline
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Table 90. UFBGA176+25, - 201-ball, 10 x 10 mm, 0.65 mm pitch,

ultra fine pitch ball grid array package mechanical data
millimeters inches(1)
Symbol
Min Typ Max Min Typ Max

A - - 0.600 - - 0.0236
A1 - - 0.110 - - 0.0043
A2 - 0.450 - - 0.0177 -
A3 - 0.130 - - 0.0051 0.0094
A4 - 0.320 - - 0.0126 -
b 0.240 0.290 0.340 0.0094 0.0114 0.0134
D 9.850 10.000 10.150 0.3878 0.3937 0.3996
D1 - 9.100 - - 0.3583 -
E 9.850 10.000 10.150 0.3878 0.3937 0.3996
E1 - 9.100 - - 0.3583 -
e - 0.650 - - 0.0256 -
Z - 0.450 - - 0.0177 -
ddd - - 0.080 - - 0.0031

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Package information STM32F21xxx

Table 90. UFBGA176+25, - 201-ball, 10 x 10 mm, 0.65 mm pitch,

ultra fine pitch ball grid array package mechanical data (continued)
millimeters inches(1)
Symbol
Min Typ Max Min Typ Max

eee - - 0.150 - - 0.0059

fff - - 0.050 - - 0.0020
1. Values in inches are converted from mm and rounded to 4 decimal digits.

Figure 86. UFBGA176+25 - 201-ball, 10 x 10 mm, 0.65 mm pitch, ultra fine pitch ball
grid array package recommended footprint

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'VP

Ϭϳͺ&Wͺsϭ

Table 91. UFBGA176+25 recommended PCB design rules (0.65 mm pitch BGA)
Dimension Recommended values

Pitch 0.65 mm
Dpad 0.300 mm
0.400 mm typ (depends on the soldermask
Dsm
registration tolerance)
Stencil opening 0.300 mm
Stencil thickness Between 0.100 mm and 0.125 mm
Pad trace width 0.100 mm

164/180 DocID17050 Rev 13

STM32F21xxx Package information

Device marking

Figure 87. UFBGA176+25 marking (package top view)

5HYLVLRQFRGH

670
3URGXFWLGHQWLILFDWLRQ
),*+

'DWHFRGH

%DOO$
LGHQWLILHU

069

1. Parts marked as “ES”, “E” or accompanied by an Engineering Sample notification letter, are not yet
qualified and therefore not yet ready to be used in production and any consequences deriving from such
usage will not be at ST charge. In no event, ST will be liable for any customer usage of these engineering
samples in production. ST Quality has to be contacted prior to any decision to use these Engineering
samples to run qualification activity.

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179
Package information STM32F21xxx

7.6 Thermal characteristics

The maximum chip-junction temperature, TJ max, in degrees Celsius, may be calculated
using the following equation:
TJ max = TA max + (PD max x ΘJA)
Where:
• TA max is the maximum ambient temperature in ° C,
• ΘJA is the package junction-to-ambient thermal resistance, in ° C/W,
• PD max is the sum of PINT max and PI/O max (PD max = PINT max + PI/Omax),
• PINT max is the product of IDD and VDD, expressed in Watts. This is the maximum chip
internal power.
PI/O max represents the maximum power dissipation on output pins where:
PI/O max = Σ (VOL × IOL) + Σ((VDD – VOH) × IOH),
taking into account the actual VOL / IOL and VOH / IOH of the I/Os at low and high level in the
application.

Table 92. Package thermal characteristics

Symbol Parameter Value Unit

Thermal resistance junction-ambient

45
LQFP 64 - 10 × 10 mm / 0.5 mm pitch
Thermal resistance junction-ambient
46
LQFP100 - 14 × 14 mm / 0.5 mm pitch
Thermal resistance junction-ambient
ΘJA 40 °C/W
LQFP144 - 20 × 20 mm / 0.5 mm pitch
Thermal resistance junction-ambient
38
LQFP176 - 24 × 24 mm / 0.5 mm pitch
Thermal resistance junction-ambient
39
UFBGA176 - 10× 10 mm / 0.5 mm pitch

Reference document
JESD51-2 Integrated Circuits Thermal Test Method Environment Conditions - Natural
Convection (Still Air). Available from www.jedec.org.

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STM32F21xxx Ordering information

8 Ordering information

Table 93. Ordering information scheme

Example: STM32 F 215 R E T 6 V xxx

Device family
STM32 = ARM-based 32-bit microcontroller

Product type
F = general-purpose

Device subfamily
215 = STM32F21x, connectivity, cryptographic acceleration
217= STM32F21x, connectivity, camera interface,
cryptographic acceleration, Ethernet

Pin count
R = 64 pins
V = 100 pins
Z = 144 pins
I = 176 pins

Flash memory size

E = 512 Kbytes of Flash memory
G = 1024 Kbytes of Flash memory

Package
T = LQFP
H = UFBGA

Temperature range
6 = Industrial temperature range, –40 to 85 °C.
7 = Industrial temperature range, –40 to 105 °C.

Software option
Internal code or Blank

Options
xxx = programmed parts
TR = tape and reel

For a list of available options (speed, package, etc.) or for further information on any aspect
of this device, contact your nearest ST sales office.

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179
Revision history STM32F21xxx

9 Revision history

Table 94. Document revision history

Date Revision Changes

02-Feb-2010 1 Initial release.

Updated datasheet status to PRELIMINARY DATA.
Renamed high-speed SRAM, system SRAM.
Added UFBGA176 package, and note 1 related to LQFP176 package in
Table 2, Figure 12, and Table 93.
Added information on ART accelerator and audio PLL (PLLI2S).
Added Table 5: USART feature comparison.
Several updates on Table 7: STM32F21x pin and ball definitions and
Table 9: Alternate function mapping. ADC, DAC, oscillator, RTC_AF,
WKUP and VBUS signals removed from alternate functions and moved
to the “other functions” column in Table 7: STM32F21x pin and ball
definitions.
TRACESWO added in Figure 4: STM32F21x block diagram, Table 7:
STM32F21x pin and ball definitions, and Table 9: Alternate function
mapping.
XTAL oscillator frequency updated on cover page, in Figure 4:
STM32F21x block diagram and in Section 3.11: External interrupt/event
controller (EXTI).
Updated list of peripherals used for boot mode in Section 3.13: Boot
modes.
Added Regulator bypass mode in Section 3.16: Voltage regulator, and
Section 6.3.4: Operating conditions at power-up / power-down
13-Jul-2010 2 (regulator OFF).
Updated Section 3.17: Real-time clock (RTC), backup SRAM and
backup registers.
Added Note Note: in Section 3.18: Low-power modes.
Added SPI TI protocol in Section 3.23: Serial peripheral interface (SPI).
Updated Section 3.28: Universal serial bus on-the-go full-speed
(OTG_FS), and Section 3.29: Universal serial bus on-the-go high-speed
(OTG_HS).
Added Section 6: Electrical characteristics, and Section 7.6: Thermal
characteristics.
Updated Table 89: LQFP176 - Low profile quad flat package 24 × 24 ×
1.4 mm package mechanical data and Figure 83: LQFP176 - Low
profile quad flat package 24 × 24 × 1.4 mm, package outline.
Added Table 93: Main applications versus package for STM32F2xxx
microcontrollers in A.1: Main applications versus package. Updated
figures in Appendix A.2: USB OTG full speed (FS) interface solutions
and A.3: USB OTG high speed (HS) interface solutions. Updated
Figure 94: Audio player solution using PLL, PLLI2S, USB and 1 crystal
and Figure 95: Audio PLL (PLLI2S) providing accurate I2S clock.
Added random number generation feature. Added trademark for ART
accelerator and updated Section 3.2: Adaptive real-time memory
accelerator (ART Accelerator™).

168/180 DocID17050 Rev 13

STM32F21xxx Revision history

Table 94. Document revision history (continued)

Date Revision Changes

Added WLCSP66 (64+2) package. Added note 1 related to LQFP176

on cover page.
Update I/Os in Section : Features.
Updated Table 5: Multi-AHB matrix.
Added case of BOR inactivation using IRROFF on WLCSP devices in
Section 3.15: Power supply supervisor.
Reworked Section 3.16: Voltage regulator to clarify regulator off modes.
Added Section 3.19: VBAT operation.
Modified VDD_3 pin in Table 7: STM32F21x pin and ball definitions, and
added note related to the FSMC_NL pin.
Renamed BYPASS-REG REGOFF, and add IRROFF pin.
Changed VSS_SA to VSS, and VDD_SA pin reserved for future use.
Updated maximum HSE crystal frequency to 26 MHz.
USART4/5 renamed UART4/5. USART4 pins renamed UART4 in
Table 7: STM32F21x pin and ball definitions. Updated LIN and IrDA
features for UART4/5 in Table 5: USART feature comparison.
Section 6.2: Absolute maximum ratings: Updated VIN minimum and
maximum values and note for non-five-volt tolerant pins in Table 10:
Voltage characteristics. Updated IINJ(PIN) maximum values and related
notes in Table 11: Current characteristics.
Updated VDDA minimum value in Table 13: General operating
conditions.
Added Note 2 and updated Maximum CPU frequency in Table 14:
25-Nov-2010 3 Limitations depending on the operating power supply range; and added
Figure 19: Number of wait states versus fCPU and VDD range.
Renamed Brownout Low, medium and High reset thresholds, Renamed
VBORL/VBORM/VBORH, VBOR1/VBOR2/VBOR3 in Table 18: Embedded
reset and power control block characteristics.
Changed fLSI typical value in Table 32: LSI oscillator characteristics.
Added Figure 33: ACCLSI versus temperature.
Changed fOSC_IN maximum value in Table 29: HSE 4-26 MHz oscillator
characteristics.
Changed fPLL_IN maximum value in Table 33: Main PLL characteristics,
and updated jitter parameters in Table 34: PLLI2S (audio PLL)
characteristics.
Section 6.3.16: I/O port characteristics: updated VIH and VIL in Table 45:
I/O static characteristics.
Added Note 1 below Table 46: Output voltage characteristics.
Updated RPD and RPU parameter description in Table 56: USB OTG FS
DC electrical characteristics.
Updated VREF+ minimum value in Table 65: ADC characteristics.
Updated Table 70: Embedded internal reference voltage.
Removed Ethernet and USB2 for 64-pin devices in Table 93: Main
applications versus package for STM32F2xxx microcontrollers.
Added A.2: USB OTG full speed (FS) interface solutions, removed
“OTG FS connection with external PHY” figure, updated Figure 85,
Figure 86, and Figure 87 to add STULPI01B.

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Table 94. Document revision history (continued)

Date Revision Changes

Changed datasheet status to “Full Datasheet”.

APB1 frequency changed form 36 MHz to 30 MHz.
Introduced concept of SRAM1 and SRAM2.
LQFP176 now in production.
Removed WLCSP64+2 package.
Updated Figure 3: Compatible board design between STM32F10x and
STM32F2xx for LQFP144 package and Figure 2: Compatible board
design between STM32F10x and STM32F2xx for LQFP100 package.
Added camera interface for STM32F217Vx devices in Table 2:
STM32F215xx and STM32F217xx: features and peripheral counts.
Removed 16 MHz internal RC oscillator accuracy in Section 3.12:
Clocks and startup.
Updated Section 3.16: Voltage regulator.
Modified I2S sampling frequency range in Section 3.12: Clocks and
startup, Section 3.24: Inter-integrated sound (I2S), and Section 3.30:
Audio PLL (PLLI2S).
Updated Section 3.17: Real-time clock (RTC), backup SRAM and
backup registers and description of TIM2 and TIM5 in Section 3.20.2:
General-purpose timers (TIMx).
Modified maximum baud rate (oversampling by 16) for USART1 in
Table 5: USART feature comparison.
Updated note related to RFU pin below Figure 10: STM32F21x
LQFP100 pinout, Figure 11: STM32F21x LQFP144 pinout, Figure 12:
22-Apr-2011 4 STM32F21x LQFP176 pinout, Figure 13: STM32F21x UFBGA176
ballout, and Table 7: STM32F21x pin and ball definitions.
Added RTC_50Hz as PB15 alternate function, and TT (3.6 V tolerant
I/O) in Table 7: STM32F21x pin and ball definitions and Table 9:
Alternate function mapping.
PA15 added in Table 7: STM32F21x pin and ball definitions.
In Table 7: STM32F21x pin and ball definitions, changed I2S2_CK and
I2S3_CK to I2S2_SCK and I2S3_SCK, respectively.
Removed ETH _RMII_TX_CLK for PC3/AF11 in Table 9: Alternate function
mapping.
Updated Table 10: Voltage characteristics and Table 11: Current
characteristics.
TSTG updated to –65 to +150 in Table 12: Thermal characteristics.
Added CEXT and ESR in Table 13: General operating conditions as well
as Section 6.3.2: VCAP1/VCAP2 external capacitor.
Modified Note 3 in Table 14: Limitations depending on the operating
power supply range.
Updated Table 16: Operating conditions at power-up / power-down
(regulator ON), and Table 17: Operating conditions at power-up / power-
down (regulator OFF).
Updated notes below and added OSC_OUT pin in Figure 15: Pin
loading conditions. and Figure 16: Pin input voltage.
Updated VPVD, VBOR1, VBOR2, VBOR3, TRSTTEMPO typical value, and
IRUSH, added ERUSH and Note 2 in Table 18: Embedded reset and
power control block characteristics.

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Table 94. Document revision history (continued)

Date Revision Changes

Updated Typical and maximum current consumption conditions, as well

as Table 20: Typical and maximum current consumption in Run mode,
code with data processing running from Flash memory (ART
accelerator disabled) and Table 19: Typical and maximum current
consumption in Run mode, code with data processing running from
Flash memory (ART accelerator enabled) or RAM. Added Figure 21,
Figure 22, Figure 23, and Figure 24.
Updated Table 21: Typical and maximum current consumption in Sleep
mode, and added Figure 25 and Figure 26.
Updated Table 23: Typical and maximum current consumptions in
Standby mode and Table 24: Typical and maximum current
consumptions in VBAT mode.
Updated Table 22: Typical and maximum current consumptions in Stop
mode. Added Figure 27: Typical current consumption vs. temperature in
Stop mode.
Updated Table 23: Typical and maximum current consumptions in
Standby mode and Table 24: Typical and maximum current
consumptions in VBAT mode.
Updated On-chip peripheral current consumption conditions and
Table 25: Peripheral current consumption.
Updated tWUSTDBY and tWUSTOP, and added Note 3 in Table 26: Low-
power mode wakeup timings.
Maximum fHSE_ext and minimum tw(HSE) values updated in Table 27:
High-speed external user clock characteristics.
4 Updated C and gm in Table 29: HSE 4-26 MHz oscillator characteristics.
22-Apr-2011 Updated RF, I2, gm, and tsu(LSE) in Table 30: LSE oscillator
(continued)
characteristics (fLSE = 32.768 kHz).
Added Note 3 and updated ACCHSI, IDD(HSI) and tsu(HSI) in Table 31:
HSI oscillator characteristics. Added Figure 32: ACCHSI versus
temperature
Updated fLSI, tsu(LSI) and IDD(LSI) in Table 32: LSI oscillator
characteristics.
Table 33: Main PLL characteristics: removed note 1, updated tLOCK,
jitter, IDD(PLL) and IDDA(PLL), added Note 2 for fPLL_IN minimum and
maximum values.
Table 34: PLLI2S (audio PLL) characteristics: removed note 1, updated
tLOCK, jitter, IDD(PLLI2S) and IDDA(PLLI2S), added Note 2 for fPLLI2S_IN
minimum and maximum values.
Added Note 1 in Table 35: SSCG parameters constraint.
Updated Table 36: Flash memory characteristics. Modified Table 37:
Flash memory programming and added Note 1 for tprog. Updated tprog
and added Note 1 in Table 38: Flash memory programming with VPP.
Modified Figure 38: Recommended NRST pin protection.
Updated Table 41: EMI characteristics and EMI monitoring conditions in
Section : Electromagnetic Interference (EMI).
Added Note 2 related to VESD(HBM)in Table 42: ESD absolute maximum
ratings.
Added Section 6.3.15: I/O current injection characteristics.
Updated Table 45: I/O static characteristics. Modified maximum
frequency values and conditions in Table 47: I/O AC characteristics.

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Table 94. Document revision history (continued)

Date Revision Changes

Updated tres(TIM) in Table 49: Characteristics of TIMx connected to the

APB1 domain. Modified tres(TIM) and fEXT Table 50: Characteristics of
TIMx connected to the APB2 domain.
Changed tw(SCKH) to tw(SCLH), tw(SCKL) to tw(SCLL), tr(SCK) to tr(SCL), and
tf(SCK) to tf(SCL) in Table 51: I2C characteristics and Figure 39: I2C bus
AC waveforms and measurement circuit.
Added Table 56: USB OTG FS DC electrical characteristics and
updated Table 57: USB OTG FS electrical characteristics.
Updated VDD minimum value in Table 61: Ethernet DC electrical
characteristics.
Updated Table 65: ADC characteristics and RAIN equation.
Updated RAIN equation. Updated Table 67: DAC characteristics.
Updated tSTART in Table 68: Temperature sensor characteristics.
Updated Table 70: Embedded internal reference voltage.
Modified FSMC_NOE waveform in Figure 55: Asynchronous non-
multiplexed SRAM/PSRAM/NOR read waveforms. Shifted end of
FSMC_NEx/NADV/addresses/NWE/NOE/NWAIT of a half FSMC_CLK
period, changed td(CLKH-NExH) to td(CLKL-NExH), td(CLKH-AIV) to td(CLKL-
AIV), td(CLKH-NOEH) to td(CLKL-NOEH), and td(CLKH-NWEH) to td(CLKL-NWEH),
4 and updated data latency from 1 to 0 in Figure 59: Synchronous
22-Apr-2011
(continued) multiplexed NOR/PSRAM read timings, Figure 60: Synchronous
multiplexed PSRAM write timings, Figure 61: Synchronous non-
multiplexed NOR/PSRAM read timings, and Figure 62: Synchronous
non-multiplexed PSRAM write timings,
Changed td(CLKH-NExH) to td(CLKL-NExH), td(CLKH-AIV) to td(CLKL-AIV),
td(CLKH-NOEH) to td(CLKL-NOEH), td(CLKH-NWEH) to td(CLKL-NWEH), and
modified tw(CLK) minimum value in Table 75, Table 76, Table 77, and
Table 78.
Updated R typical value in Table 69: VBAT monitoring
characteristics.Updated note 2 in Table 71, Table 72, Table 73,
Table 74, Table 75, Table 76, Table 77, and Table 78.
Modified th(NIOWR-D) in Figure 68: PC Card/CompactFlash controller
waveforms for I/O space write access.
Modified FSMC_NCEx signal in Figure 69: NAND controller waveforms
for read access, Figure 70: NAND controller waveforms for write
access, Figure 71: NAND controller waveforms for common memory
read access, and Figure 72: NAND controller waveforms for common
memory write access.
Specified Full speed (FS) mode for Figure 86: USB OTG HS peripheral-
only connection in FS mode and Figure 87: USB OTG HS host-only
connection in FS mode.

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Table 94. Document revision history (continued)

Date Revision Changes

Added SDIO in Table 2: STM32F215xx and STM32F217xx: features

and peripheral counts.
Updated VIN for 5V tolerant pins in Table 10: Voltage characteristics.
Updated jitter parameters description in Table 33: Main PLL
characteristics.
Remove jitter values for system clock in Table 34: PLLI2S (audio PLL)
characteristics.
Updated Table 41: EMI characteristics.
Update Note 2 in Table 51: I2C characteristics.
Updated Avg_Slope typical value and TS_temp minimum value in
14-Jun-2011 5 Table 68: Temperature sensor characteristics.
Updated TS_vbat minimum value in Table 69: VBAT monitoring
characteristics.
Updated TS_vrefint minimum value in Table 70: Embedded internal
reference voltage.
Added Software option in Section 8: Ordering information.
In Table 93: Main applications versus package for STM32F2xxx
microcontrollers, renamed USB1 and USB2, USB OTG FS and USB
OTG HS, respectively; and removed USB OTG FS and camera
interface for 64-pin package; added USB OTG HS on 64-pin package;
and added Note 1 and Note 2.
Updated disclaimer on cover page.

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Table 94. Document revision history (continued)

Date Revision Changes

Updated SDIO register addresses in Figure 14: Memory map.

Updated Figure 3: Compatible board design between STM32F10x and
STM32F2xx for LQFP144 package, Figure 2: Compatible board design
between STM32F10x and STM32F2xx for LQFP100 package, Figure 1:
Compatible board design between STM32F10x and STM32F2xx for
LQFP64 package, and added Figure 4: Compatible board design
between STM32F10xx and STM32F2xx for LQFP176 package.
Updated Section 3.3: Memory protection unit.
Updated Section 3.6: Embedded SRAM.
Updated Section 3.28: Universal serial bus on-the-go full-speed
(OTG_FS) to remove external FS OTG PHY support.
In Table 7: STM32F21x pin and ball definitions: changed SPI2_MCK
and SPI3_MCK to I2S2_MCK and I2S3_MCK, respectively. Added ETH
_RMII_TX_EN alternate function to PG11. Added EVENTOUT in the list
of alternate functions for I/O pin/balls. Removed OTG_FS_SDA,
OTG_FS_SCL and OTG_FS_INTN alternate functions.
In Table 9: Alternate function mapping: changed I2S3_SCK to
I2S3_MCK for PC7/AF6, added FSMC_NCE3 for PG9, FSMC_NE3 for
PG10, and FSMC_NCE2 for PD7. Removed OTG_FS_SDA,
OTG_FS_SCL and OTG_FS_INTN alternate functions. Updated
peripherals corresponding to AF12.
20-Dec-2011 6 Removed CEXT and ESR from Table 13: General operating conditions.
Added maximum power consumption at TA=25 °C in Table 22: Typical
and maximum current consumptions in Stop mode.
Added CRYPTO, RNG, and HASH consumption in Table 25: Peripheral
current consumption.
Updated md minimum value in Table 35: SSCG parameters constraint.
Added examples in Section 6.3.11: PLL spread spectrum clock
generation (SSCG) characteristics.
Updated Table 53: SPI characteristics and Table 54: I2S characteristics.
Updated Figure 46: ULPI timing diagram and Table 60: ULPI timing.
Updated Table 62: Dynamics characteristics: Ethernet MAC signals for
SMI, Table 63: Dynamics characteristics: Ethernet MAC signals for
RMII, and Table 64: Dynamics characteristics: Ethernet MAC signals for
MII.
Updated maximum fS values in Table 65: ADC characteristics.
Section 6.3.25: FSMC characteristics: updated Table 71 toTable 82,
changed CL value to 30 pF, and modified FSMC configuration for
asynchronous timings and waveforms. Updated Figure 60:
Synchronous multiplexed PSRAM write timings.
UpdatedTable 83: DCMI characteristics.
Updated Table 90: UFBGA176+25 - ultra thin fine pitch ball grid array 10
× 10 × 0.6 mm mechanical data.

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Table 94. Document revision history (continued)

Date Revision Changes

Appendix A.2: USB OTG full speed (FS) interface solutions: updated
Figure 85: USB OTG FS (full speed) host-only connection and added
Note 2, updated Figure 86: OTG FS (full speed) connection dual-role
with internal PHY and added Note 3 and Note 4, modified Figure 87:
OTG HS (high speed) device connection, host and dual-role in high-
speed mode with external PHY and added Note 2.
6
20-Dec-2011 Appendix A.3: USB OTG high speed (HS) interface solutions:
(continued)
removed figures USB OTG HS device-only connection in FS mode and
USB OTG HS host-only connection in FS mode, updated Figure 87:
OTG HS (high speed) device connection, host and dual-role in high-
speed mode with external PHY.
Added Appendix A.4: Ethernet interface solutions.
Updated disclaimer on last page.

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Table 94. Document revision history (continued)

Date Revision Changes

Updated number of USB OTG HS and FS, added Note 1 related to

FSMC and Note 3 related to SPI/I2S in Table 2: STM32F215xx and
STM32F217xx: features and peripheral counts.
Added Note 2 and update TIM5 in Figure 4: STM32F21x block diagram.
Updated maximum number of maskable interrupts in Section 3.10:
Nested vectored interrupt controller (NVIC).
Removed STM32F215xx in Section 3.28: Universal serial bus on-the-go
full-speed (OTG_FS).
Removed support of I2C for OTG PHY in Section 3.29: Universal serial
bus on-the-go high-speed (OTG_HS).
Removed OTG_HS_SCL, OTG_HS_SDA, OTG_FS_INTN in Table 7:
STM32F21x pin and ball definitions and Table 9: Alternate function
mapping.
PH10 alternate function TIM5_CH1_ETR renamed TIM5_CH1.
Added Table 8: FSMC pin definition.
Updated VPOR/PDR in Table 18: Embedded reset and power control
block characteristics.
Updated VDDA and VREF+ decoupling capacitor in Figure 17: Power
supply scheme.
Updated typical values in Table 23: Typical and maximum current
consumptions in Standby mode and Table 24: Typical and maximum
24-Apr-2012 7 current consumptions in VBAT mode.
Updated Table 29: HSE 4-26 MHz oscillator characteristics and
Table 30: LSE oscillator characteristics (fLSE = 32.768 kHz).
Updated Table 36: Flash memory characteristics, Table 37: Flash
memory programming, and Table 38: Flash memory programming with
VPP.
Updated Section : Output driving current.
Updated Note 3 and removed note related to minimum hold time value
in Table 51: I2C characteristics.
Updated Table 63: Dynamics characteristics: Ethernet MAC signals for
RMII.
Updated CADC, IVREF+, and IVDDA in Table 65: ADC characteristics.
Updated note concerning ADC accuracy vs. negative injection current
below Table 66: ADC accuracy.
Updated Figure 85: UFBGA176+25 - ultra thin fine pitch ball grid array
10 × 10 × 0.6 mm, package outline.
Appendix A.1: Main applications versus package: removed number of
address lines for FSMC/NAND in Table 93: Main applications versus
package for STM32F2xxx microcontrollers.
Appendix A.4: Ethernet interface solutions: updated Figure 92:
Complete audio player solution 1 and Figure 93: Complete audio player
solution 2.

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Table 94. Document revision history (continued)

Date Revision Changes

Removed Figure 4. Compatible board design between STM32F10xx

and STM32F2xx for LQFP176 package.
Updated number of AHB buses in Section 2: Description and
Section 3.12: Clocks and startup.
Updated Note 2 below Figure 4: STM32F21x block diagram.
Changed System memory to System memory + OTP in Figure 14:
Memory map.
Added Note 1 below Table 15: VCAP1/VCAP2 operating conditions.
Updated VDDA and VREF+ decoupling capacitor in Figure 17: Power
supply scheme and updated Note 3.
Changed simplex mode into half-duplex mode in Section 3.24: Inter-
integrated sound (I2S).
Replaced DAC1_OUT and DAC2_OUT by DAC_OUT1 and
DAC_OUT2, respectively.
Changed TIM2_CH1/TIM2_ETR into TIM2_CH1_ETR for PA0 and PA5
in Table 9: Alternate function mapping.
Updated note applying to IDD (external clock and all peripheral disabled)
in Table 20: Typical and maximum current consumption in Run mode,
code with data processing running from Flash memory (ART
accelerator disabled). Updated Note 3 below Table 21: Typical and
maximum current consumption in Sleep mode.
Removed fHSE_ext typical value in Table 27: High-speed external user
clock characteristics.
Updated master I2S clock jitter conditions and values in Table 34:
29-Oct-2012 8 PLLI2S (audio PLL) characteristics.
Updated equations in Section 6.3.11: PLL spread spectrum clock
generation (SSCG) characteristics.
Swapped TTL and CMOS port conditions for VOL and VOH in Table 46:
Output voltage characteristics. Updated VIL(NRST) and VIH(NRST) in
Table 48: NRST pin characteristics.
Updated Table 53: SPI characteristics and Table 54: I2S
characteristics.Removed note 1 related to measurement points below
Figure 41: SPI timing diagram - slave mode and CPHA = 1, Figure 42:
SPI timing diagram - master mode, and Figure 43: I2S slave timing
diagram (Philips protocol)(1).
Updated tHC in Table 60: ULPI timing.
Updated Figure 47: Ethernet SMI timing diagram, Table 62: Dynamics
characteristics: Ethernet MAC signals for SMI and Table 63: Dynamics
characteristics: Ethernet MAC signals for RMII.
Update fTRIG in Table 65: ADC characteristics. Updated IDDA description
in Table 67: DAC characteristics.
Updated note below Figure 52: Power supply and reference decoupling
(VREF+ not connected to VDDA) and Figure 53: Power supply and
reference decoupling (VREF+ connected to VDDA).
Replaced td(CLKL-NOEL) by td(CLKH-NOEL) in Table 75: Synchronous
multiplexed NOR/PSRAM read timings, Table 77: Synchronous non-
multiplexed NOR/PSRAM read timings, Figure 59: Synchronous
multiplexed NOR/PSRAM read timings and Figure 61: Synchronous
non-multiplexed NOR/PSRAM read timings.

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Table 94. Document revision history (continued)

Date Revision Changes

Added Figure 84: LQFP176 recommended footprint.

Added Note 2 below Figure 86: Regulator OFF/internal reset ON.
8
29-Oct-2012
(continued) Updated device subfamily in Table 93: Ordering information scheme.
Remove reference to note 2 for USB IOTG FS in Table 93: Main
applications versus package for STM32F2xxx microcontrollers.
Updated Section 3.14: Power supply schemes, Section 3.15: Power
supply supervisor, Section 3.16.1: Regulator ON and Section 3.16.2:
Regulator OFF. Added Section 3.16.3: Regulator ON/OFF and internal
reset ON/OFF availability.
Restructured RTC features and added reference clock detection in
Section 3.17: Real-time clock (RTC), backup SRAM and backup
registers.
Added note indicating the package view below Figure 9: STM32F21x
LQFP64 pinout, Figure 10: STM32F21x LQFP100 pinout, Figure 11:
STM32F21x LQFP144 pinout, and Figure 12: STM32F21x LQFP176
pinout.
Added Table 6: Legend/abbreviations used in the pinout table.
Table 7: STM32F21x pin and ball definitions: content reformatted,
removed indexes on VSS and VDD, updated PA4, PA5, PA6, PC4,
BOOT0; replaced DCMI_12 by DCMI_D12, ETH_MII_RX_D0 by
ETH_MII_RXD0, ETH_MII_RX_D1 by ETH_MII_RXD1,
ETH_RMII_RX_D0 by ETH_RMII_RXD0, and ETH_RMII_RX_D1 by
ETH_RMII_RXD1 in .
Table 9: Alternate function mapping: replaced FSMC_BLN1 by
FSMC_NBL1, added EVENTOUT as AF15 alternated function for
PC13, PC14, PC15, PH0, PH1, and PI8.
04-Nov-2013 9
Updated Figure 15: Pin loading conditions and Figure 16: Pin input
voltage.
Added VIN in Table 13: General operating conditions.
Removed note applying to VPOR/PDR minimum value in Table 18:
Embedded reset and power control block characteristics.
Updated notes related to CL1 and CL2 in Section : Low-speed external
clock generated from a crystal/ceramic resonator.
Updated conditions in Table 40: EMS characteristics. Updated Table 41:
EMI characteristics. Updated VIL, VIH and VHys in Table 45: I/O static
characteristics. Added Section : Output driving current and updated
Figure 37: I/O AC characteristics definition.
Updated VIL(NRST) and VIH(NRST) in Table 48: NRST pin characteristics,
updated Figure 37: I/O AC characteristics definition.
Removed tests conditions in Section : I2C interface characteristics.
Updated Table 51: I2C characteristics and Figure 39: I2C bus AC
waveforms and measurement circuit.
Updated IVREF+ and IVDDA in Table 65: ADC characteristics.
Updated Offset comments in Table 67: DAC characteristics.
Updated minimum th(CLKH-DV) value in Table 77: Synchronous non-
multiplexed NOR/PSRAM read timings.

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Table 94. Document revision history (continued)

Date Revision Changes

Updated Figure 75: LQFP64 – 10 x 10 mm 64 pin low-profile quad flat

package outline and Table 86: LQFP64 – 10 x 10 mm 64 pin low-profile
quad flat package mechanical data. Updated Figure 77: LQFP100, 14 x
14 mm 100-pin low-profile quad flat package outline, Figure 80:
LQFP144, 20 x 20 mm, 144-pin low-profile quad flat package outline,
9
04-Nov-2013 Figure 83: LQFP176 - Low profile quad flat package 24 × 24 × 1.4 mm,
(continued)
package outline. Updated Figure 85: UFBGA176+25 - ultra thin fine
pitch ball grid array 10 × 10 × 0.6 mm, package outline and Figure 85:
UFBGA176+25 - ultra thin fine pitch ball grid array 10 × 10 × 0.6 mm,
package outline.
Removed Appendix A Application block diagrams.
Updated VBAT voltage range in Figure 17: Power supply scheme. Added
caution note in Section 6.1.6: Power supply scheme.
Updated VIN in Table 13: General operating conditions.
Removed note 1 in Table 22: Typical and maximum current
consumptions in Stop mode.
27-Oct-2014 10
Updated Table 44: I/O current injection susceptibility, Section 6.3.16:
I/O port characteristics and Section 6.3.17: NRST pin characteristics.
Removed note 3 in Table 68: Temperature sensor characteristics.
Added Figure 79: LQFP100 marking (package top view) and Figure 82:
LQFP144 marking (package top view).
Updated Section 1: Introduction.
Updated Table 31: HSI oscillator characteristics and its footnotes.
Updated Figure 34: PLL output clock waveforms in center spread mode,
Figure 35: PLL output clock waveforms in down spread mode,
23-Feb-2016 11
Figure 52: Power supply and reference decoupling (VREF+ not
connected to VDDA) and Figure 53: Power supply and reference
decoupling (VREF+ connected to VDDA).
Updated Section 7: Package information and its subsections.
Updated Features and Section 2: Description.
Updated figures 1, 2 and 3 in Section 2.1: Full compatibility throughout
the family.
Updated Device marking and Figure 79 in Section 7.2: LQFP100
package information.
07-Jul-2016 12
Updated Device marking and Figure 82 in Section 7.3: LQFP144
package information.
Updated Section 7.5: UFBGA176+25 package information with
introduction of Device marking and Figure 87.
Updated Table 93: Ordering information scheme.
Updated Figure 52: Power supply and reference decoupling (VREF+
16-Aug-2016 13 not connected to VDDA).
Updated title of Section 8: Ordering information.

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 STM32F21xxx

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