ESP8266

AT Instruction Set

Version 3.0.1
Espressif Systems
Copyright © 2019

www.espressif.com
 About This Guide
This document provides AT commands list based on ESP8266_NONOS_SDK.

Release Notes

Date Version Release notes

2016.04 V1.5.3 First Release.

2016.05 V1.5.4 Updated Section 5.2.16 and Section 5.2.19

2016.07 V2.0.0 Added Section 3.2.11, updated Section 1.2

2017.05 V2.1.0 Updated Section 3.2, Section 4.1 and Section 5.2.

2017.08 V2.1.1 Added Appendix B.

Added Section 3.2.22, 3.2.23, 4.2.39, 4.2.40, 5.2.15

2018.02 V2.2
Updated 4.2.7, 4.2.8, and Appendix B.

2018.05 V2.2.1 Updated 4.2.10, 4.2.11 and 4.2.12

Added Section 5.2.11, 5.2.23, 5.2.24

2018.05 V2.2.2
Updated Section 3.2.10.

Added Section 5.2.5, 5.2.25, 5.2.26, 5.2.27

Updated Chapter 1, and Section 4.2.3, 4.2.4, 4.2.11,

2018.08 V3.0
4.2.12, Appendix A

Remove AT+RFAUTOTRACE command.

2019.02 V3.0.1 Updated Section 5.2.5, 5.2.30, 5.2.31.

Documentation Change Notification

Espressif provides email notifications to keep customers updated on changes to technical
documentation. Please subscribe here.

Certifications
Please download the product certification(s) here.

 Table of Contents
1. Overview ................................................................................................................................................1
1.1. Customize AT Firmware .............................................................................................................................. 1

1.1.1. Compiling AT project .....................................................................................................................1

1.1.2. Customize AT Functions ................................................................................................................ 1

1.1.3. Add User-Defined AT Commands ................................................................................................. 1

1.2. Downloading AT Firmware into the Flash ...................................................................................................2

1.2.1. 16 Mbit Flash, Map: 1024 KB + 1024 KB ......................................................................................3

1.2.2. 32 Mbit Flash, Map: 1024 KB + 1024 KB ......................................................................................3

1.2.3. 4 Mbit Flash ................................................................................................................................... 3

1.2.4. 8 Mbit Flash ................................................................................................................................... 4

1.2.5. 16 Mbit Flash, Map: 512 KB + 512 KB .......................................................................................... 4

1.2.6. 32 Mbit Flash, Map: 512 KB + 512 KB .......................................................................................... 5

2. Command Description ..........................................................................................................................6

3. Basic AT Commands .............................................................................................................................7

3.1. Overview .....................................................................................................................................................7

3.2. Commands ................................................................................................................................................. 8

3.2.1. AT—Tests AT Startup .....................................................................................................................8

3.2.2. AT+RST—Restarts the Module .....................................................................................................8

3.2.3. AT+GMR—Checks Version Information ........................................................................................ 8

3.2.4. AT+GSLP—Enters Deep-sleep Mode ........................................................................................... 8

3.2.5. ATE—AT Commands Echoing .......................................................................................................9

3.2.6. AT+RESTORE—Restores the Factory Default Settings ................................................................9

3.2.7. AT+UART_CUR—Current UART Configuration; Not Saved in the Flash ...................................... 9

3.2.8. AT+UART_DEF—Default UART Configuration; Saved in the Flash .............................................11

3.2.9. AT+SLEEP—Configures the Sleep Modes ..................................................................................12

3.2.10. AT+WAKEUPGPIO—Configures a GPIO to Wake ESP8266 up from Light-sleep Mode ............12

3.2.11. AT+RFPOWER—Sets the Maximum Value of RF TX Power ....................................................... 13

3.2.12. AT+RFVDD—Sets RF TX Power According to VDD33 ................................................................13

3.2.13. AT+SYSRAM—Checks the Remaining Space of RAM ...............................................................14

3.2.14. AT+SYSADC—Checks the Value of ADC ....................................................................................14

 3.2.15. AT+SYSIOSETCFG—Configures IO Working Mode .................................................................... 14

3.2.16. AT+SYSIOGETCFG—Checks the Working Modes of IO Pins ..................................................... 14

3.2.17. AT+SYSGPIODIR—Configures the Direction of a GPIO ............................................................. 15

3.2.18. AT+SYSGPIOWRITE—Configures the Output Level of a GPIO ..................................................15

3.2.19. AT+SYSGPIOREAD—Reads the GPIO Input Level ..................................................................... 16

3.2.20. AT+SYSMSG_CUR—Set Current System Messages .................................................................16

3.2.21. AT+SYSMSG_DEF—Set Default System Messages ...................................................................18

4. Wi-Fi AT Commands ...........................................................................................................................19

4.1. Overview ...................................................................................................................................................19

4.2. Commands ............................................................................................................................................... 21

4.2.1. AT+CWMODE_CUR—Sets the Current Wi-Fi mode; Configuration Not Saved in the Flash ...... 21

4.2.2. AT+CWMODE_DEF—Sets the Default Wi-Fi mode; Configuration Saved in the Flash ..............21

4.2.3. AT+CWJAP_CUR—Connects to an AP; Configuration Not Saved in the Flash .......................... 22

4.2.4. AT+CWJAP_DEF—Connects to an AP; Configuration Saved in the Flash .................................23

4.2.5. AT+CWLAPOPT—Sets the Configuration for the Command AT+CWLAP .................................. 24

4.2.6. AT+CWLAP—Lists Available APs ................................................................................................ 24

4.2.7. AT+CWQAP—Disconnects from the AP ..................................................................................... 26

4.2.8. AT+CWSAP_CUR—Configures the ESP8266 SoftAP; Configuration Not Saved in the Flash .... 26

4.2.9. AT+CWSAP_DEF—Configures the ESP8266 SoftAP; Configuration Saved in the Flash ...........27

4.2.10. AT+CWLIF—IP of Stations to Which the ESP8266 SoftAP is Connected ................................... 27

4.2.11. AT+CWDHCP_CUR—Enables/Disables DHCP; Configuration Not Saved in the Flash .............28

4.2.12. AT+CWDHCP_DEF—Enables/Disables DHCP; Configuration Saved in the Flash ..................... 28

4.2.13. AT+CWDHCPS_CUR—Sets the IP Address Allocated by ESP8266 SoftAP DHCP;

Configuration Not Saved in Flash ...............................................................................................................29

4.2.14. AT+CWDHCPS_DEF—Sets the IP Address Allocated by ESP8266 SoftAP DHCP; Configuration

Saved in Flash .............................................................................................................................................29

4.2.15. AT+CWAUTOCONN—Auto-Connects to the AP or Not ............................................................. 30

4.2.16. AT+CIPSTAMAC_CUR—Sets the MAC Address of the ESP8266 Station; Configuration Not
Saved in the Flash .......................................................................................................................................30

4.2.17. AT+CIPSTAMAC_DEF—Sets the MAC Address of the ESP8266 Station; Configuration Saved in
the Flash ......................................................................................................................................................31

4.2.18. AT+CIPAPMAC_CUR—Sets the MAC Address of the ESP8266 SoftAP; Configuration Not
Saved in the Flash .......................................................................................................................................31

4.2.19. AT+CIPAPMAC_DEF—Sets the MAC Address of the ESP8266 SoftAP; Configuration Saved in
Flash ............................................................................................................................................................31

 4.2.20. AT+CIPSTA_CUR—Sets the Current IP Address of the ESP8266 Station; Configuration Not
Saved in the Flash .......................................................................................................................................32

4.2.21. AT+CIPSTA_DEF—Sets the Default IP Address of the ESP8266 Station; Configuration Saved in
the Flash ......................................................................................................................................................32

4.2.22. AT+CIPAP_CUR—Sets the IP Address of the ESP8266 SoftAP; Configuration Not Saved in the
Flash ............................................................................................................................................................33

4.2.23. AT+CIPAP_DEF—Sets the Default IP Address of the ESP8266 SoftAP; Configuration Saved in
the Flash ......................................................................................................................................................34

4.2.24. AT+CWSTARTSMART—Starts SmartConfig ...............................................................................34

4.2.25. AT+CWSTOPSMART—Stops SmartConfig ................................................................................35

4.2.26. AT+CWSTARTDISCOVER—Enables the Mode that ESP8266 can be Found by WeChat ..........35

4.2.27. AT+CWSTOPDISCOVER—Disables the Mode that ESP8266 can be Found by WeChat ..........36

4.2.28. AT+WPS—Enables the WPS Function ........................................................................................ 36

4.2.29. AT+MDNS—Configures the MDNS Function .............................................................................. 36

4.2.30. AT+CWHOSTNAME—Configures the Name of ESP8266 Station ..............................................37

4.2.31. AT+CWCOUNTRY_CUR—Set ESP8266 WiFi Country Code; Configuration Not Saved in the
Flash ............................................................................................................................................................37

4.2.32. AT+CWCOUNTRY_DEF—Set the default WiFi Country Code of ESP8266; Configuration Saved
in the Flash ..................................................................................................................................................38

5. TCP/IP-Related AT Commands ..........................................................................................................39

5.1. Overview ...................................................................................................................................................39

5.2. Commands ............................................................................................................................................... 41

5.2.1. AT+CIPSTATUS—Gets the Connection Status ........................................................................... 41

5.2.2. AT+CIPDOMAIN—DNS Function ................................................................................................ 41

5.2.3. AT+CIPSTART—Establishes TCP Connection, UDP Transmission or SSL Connection .............42

5.2.4. AT+CIPSSLSIZE—Sets the Size of SSL Buffer ........................................................................... 44

5.2.5. AT+CIPSSLCCONF - Sets Configuration of ESP SSL Client ...................................................... 44

5.2.6. AT+CIPSEND—Sends Data ......................................................................................................... 45

5.2.7. AT+CIPSENDEX—Sends Data ....................................................................................................46

5.2.8. AT+CIPSENDBUF—Writes Data into the TCP-Send-Buffer ........................................................ 46

5.2.9. AT+CIPBUFRESET—Resets the Segment ID Count ...................................................................47

5.2.10. AT+CIPBUFSTATUS—Checks the Status of the TCP-Send-Buffer ............................................ 48

5.2.11. AT+CIPCHECKSEQ—Checks If a Specific Segment Was Successfully Sent ............................48

5.2.12. AT+CIPCLOSEMODE—Set the Close Mode of TCP Connection .............................................49

5.2.13. AT+CIPCLOSE—Closes the TCP/UDP/SSL Connection ............................................................ 49

5.2.14. AT+CIFSR—Gets the Local IP Address ...................................................................................... 49

 5.2.15. AT+CIPMUX—Enable or Disable Multiple Connections ..............................................................50

5.2.16. AT+CIPSERVER—Deletes/Creates TCP Server .......................................................................... 50

5.2.17. AT+CIPSERVERMAXCONN—Set the Maximum Connections Allowed by Server ..................... 51

5.2.18. AT+CIPMODE—Sets Transmission Mode ...................................................................................51

5.2.19. AT+SAVETRANSLINK—Saves the Transparent Transmission Link in Flash ...............................52

5.2.20. AT+CIPSTO—Sets the TCP Server Timeout ...............................................................................53

5.2.21. AT+PING—Ping Packets ............................................................................................................. 53

5.2.22. AT+CIUPDATE—Updates the Software Through Wi-Fi ...............................................................54

5.2.23. AT+CIPDINFO—Shows the Remote IP and Port with +IPD ........................................................ 54

5.2.24. +IPD—Receives Network Data ...................................................................................................54

5.2.25. AT+CIPRECVMODE—Set TCP Receive Mode ........................................................................... 55

5.2.26. AT+CIPRECVDATA—Get TCP Data in Passive Receive Mode ................................................... 55

5.2.27. AT+CIPRECVLEN—Get TCP Data Length in Passive Receive Mode ......................................... 56

5.2.28. AT+CIPSNTPCFG—Sets the Configuration of SNTP ..................................................................56

5.2.29. AT+CIPSNTPTIME—Checks the SNTP Time .............................................................................. 56

5.2.30. AT+CIPDNS_CUR—Sets User-defined DNS Servers; Configuration Not Saved in the Flash .... 57

5.2.31. AT+CIPDNS_DEF—Sets User-defined DNS Servers; Configuration Saved in the Flash ............58

A. Appendix A ..........................................................................................................................................59

B. Appendix B ..........................................................................................................................................60

C. Q&A ......................................................................................................................................................61
 1. Overview
!

1. Overview
ESP8266 AT Firmware, officially launched by Espressif, is available for download and can be used
directly. Also, users may find AT Project that Espressif specially created for users to customize AT
firmware.
This document introduces how to customize AT firmware and download AT firmware into flash. It also
provides detailed information about the AT instruction set.

⚠ Notes:

• Please make sure that correct BIN (/ESP8266_NONOS_SDK/bin/at) is already in the ESP8266 module before
using the AT commands listed in this document.

• AT firmware uses priority levels 0 and 1 of system_os_task, so only one task of priority 2 is allowed to be set up by
the user application.

1.1. Customize AT Firmware

1.1.1. Compiling AT project
If users want to customize AT source code, or add customized AT commands, please copy the folder
at in examples to the root directory of the corresponding ESP8266_NONOS_SDK , and then enter
ESP8266_NONOS_SDK/at folder to develop and compile AT project. For details, please refer to
ESP8266 Getting Started Guide.

1.1.2. Customize AT Functions

• OTA：

- The official AT firmware launched by Espressif supports the command AT+CIUPDATE by default,
which helps update AT firmware to the latest version from Espressif Cloud.
- For the customized AT firmware, users have to implement this function by themselves to update
the firmware from their own cloud. Please refer to the OTA example that Espressif introduced in
at_upgrade.c.

• SmartConfig：

- The official AT firmware launched by Espressif supports the commands AT+CWSTARTSMART

and AT+CWSTOPSMART.
- If users don’t need SmartConfig, you can compile AT Project and disable
CONFIG_AT_SMARTCONFIG_COMMAND_ENABLE in user_config.h for smaller bin size and
more memory.

1.1.3. Add User-Defined AT Commands

Please use only English letters when naming user-defined AT commands. The AT command name
must NOT contain characters or numbers.

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 1. Overview
!

AT firmware is based on ESP8266_NONOS_SDK. Espressif Systems’ AT commands are provided in

libat.a, which is included in the AT BIN firmware. Examples of customized, user-defined AT
commands are provided in ESP8266_NONOS_SDK/example/at.
Examples of implementing user-defined AT commands are provided in /ESP8266_NONOS_SDK/
examples/at/user/user_main.c. The structure, at_funcationType, is used to define four types of a
command, for details of which please refer to the following table.

Definition Type Description

AT Command AT+TEST=?

Registered Callback In Example at_testCmdTest

at_testCmd Test
Function Design Return the value range of parameters

If at_testCmd is registered as NULL, there will be no testing command.

AT Command AT+TEST?

Registered Callback In Example at_queryCmdTest

at_queryCmd Query
Function Design Return the current value

If at_queryCmd is registered as NULL, there will be no Query Command.

AT Command AT+TEST=parameter1, parameter2, …

Registered Callback In Example at_setupCmdTest

at_setupCmd Set
Function Design Set configuration

If at_setupCmd is registered as NULL, there will be no setup command.

AT Command AT+TEST

Registered Callback In Example at_exeCmdTest

at_exeCmd Execute
Function Design Execute an action

If at_exeCmd is registered as NULL, there will be no execution command.

1.2. Downloading AT Firmware into the Flash

Please refer to ESP8266_NONOS_SDK/bin/at/readme.txt for instructions on how to download AT
firmware into flash. Please use Espressif’s official Flash Download Tools to download the firmware.
Make sure you select the corresponding flash size.
Espressif’s official Flash Download Tools:

http://espressif.com/en/support/download/other-tools?keys=&field_type_tid%5B%5D=14.
Since ESP8266_NONOS_SDK_V3.0.0, AT_V1.7, limited by the size of the AT bin files, only 1024 KB
+1024 KB flash map is supported by default.

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 1. Overview
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1.2.1. 16 Mbit Flash, Map: 1024 KB + 1024 KB

Use Espressif Flash download tool and select flash size: 16 Mbit-C1.

BIN Address Description

blank.bin 0x1FB000 Initializes RF_CAL parameter area.

Stores default RF parameter values, has to be downloaded into

flash at least once.
esp_init_data_default.bin 0x1FC000
If the RF_CAL parameter area is initialized, this bin has to be
downloaded too.

blank.bin 0xFE000 Initializes Flash user parameter area, more details in Appendix.

Initializes Flash system parameter area, more details in

blank.bin 0x1FE000
Appendix.

boot.bin 0x00000 In /bin/at.

user1.2048.new.5.bin 0x01000 In /bin/at/1024+1024.

1.2.2. 32 Mbit Flash, Map: 1024 KB + 1024 KB

Use Espressif Flash download tool and select flash size: 32 Mbit-C1.

BIN Address Description

blank.bin 0x3FB000 Initializes RF_CAL parameter area

Stores default RF parameter values, has to be downloaded into

flash at least once.
esp_init_data_default.bin 0x3FC000
If the RF_CAL parameter area is initialized, this bin has to be
downloaded too.

blank.bin 0xFE000 Initializes Flash user parameter area, more details in Appendix.

Initializes Flash system parameter area, more details in

blank.bin 0x3FE000
Appendix.

boot.bin 0x00000 In /bin/at.

user1.2048.new.5.bin 0x01000 In /bin/at/1024+1024.

1.2.3. 4 Mbit Flash

With the release of ESP8266_NONOS_SDK_V2.0.0, AT_V1.3, AT firmware can use 4-Mbit flash but
does not supports FOTA (upgrade AT firmware through Wi-Fi) function.

BIN Address Description

blank.bin 0x78000 Initializes the RF_CAL parameter area.

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 1. Overview
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BIN Address Description

Stores the default RF parameter values; the BIN has to be

downloaded into flash at least once.
esp_init_data_default.bin 0x7C000
If the RF_CAL parameter area is initialized, this BIN has to be
downloaded too.

Initializes the flash user parameter area; for more details please
blank.bin 0x7A000
see Appendix.

Initializes Flash system parameter area; for more details please

blank.bin 0x7E000
see Appendix.

eagle.flash.bin 0x00000 In /bin/at/noboot.

eagle.irom0text.bin 0x10000 In /bin/at/noboot.

1.2.4. 8 Mbit Flash

If the flash size is 8 Mbit or larger, users can use boot mode which supports AT firmware upgrade
feature through Wi-Fi by command AT+CIUPDATE. Use Espressif Flash download tool and select flash
size: 8 Mbit.

BIN Address Description

blank.bin 0xFB000 Initializes the RF_CAL parameter area.

Stores the default RF parameter values; the BIN has to be

downloaded into flash at least once.
esp_init_data_default.bin 0xFC000
If the RF_CAL parameter area is initialized, this BIN has to be
downloaded too.

Initializes the flash user parameter area; for more details please
blank.bin 0x7E000
see Appendix.

Initializes the flash system parameter area; for more details

blank.bin 0xFE000
please see Appendix.

boot.bin 0x00000 In /bin/at

user1.1024.new.2.bin 0x01000 In /bin/at/512+512

1.2.5. 16 Mbit Flash, Map: 512 KB + 512 KB

Use Espressif Flash download tool and select flash size: 16 Mbit.

BIN Address Description

blank.bin 0x1FB000 Initializes RF_CAL parameter area.

Stores default RF parameter values, has to be downloaded into

flash at least once.
esp_init_data_default.bin 0x1FC000
If the RF_CAL parameter area is initialized, this bin has to be
downloaded too.

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BIN Address Description

blank.bin 0x7E000 Initializes Flash user parameter area, more details in Appendix.

Initializes Flash system parameter area, more details in

blank.bin 0x1FE000
Appendix.

boot.bin 0x00000 In /bin/at.

user1.1024.new.2.bin 0x01000 In /bin/at/512+512.

1.2.6. 32 Mbit Flash, Map: 512 KB + 512 KB

Use Espressif Flash download tool and select flash size: 32 Mbit.

BIN Address Description

blank.bin 0x3FB000 Initializes RF_CAL parameter area.

Stores default RF parameter values, has to be downloaded into

flash at least once.
esp_init_data_default.bin 0x3FC000
If the RF_CAL parameter area is initialized, this bin has to be
downloaded too.

blank.bin 0x7E000 Initializes Flash user parameter area, more details in Appendix.

Initializes Flash system parameter area, more details in

blank.bin 0x3FE000
Appendix.

boot.bin 0x00000 In /bin/at.

user1.1024.new.2.bin 0x01000 In /bin/at/512+512.

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 2. Command Description
!

2. Command Description
Each command set contains four types of AT commands.

Type Command Format Description

Queries the Set Commands’ internal parameters and their range of

Test Command AT+<x>=?
values.

Query Command AT+<x>? Returns the current value of parameters.

Sets the value of user-defined parameters in commands, and runs these

Set Command AT+<x>=<…>
commands.

Execute Command AT+<x> Runs commands with no user-defined parameters.

⚠ Notice:

• Not all AT commands support all four variations mentioned above.

• Square brackets [ ] designate the default value; it is either not required or may not appear.

• String values need to be included in double quotation marks, for example: AT+CWSAP="ESP756290","21030826",
1,4.

• The default baud rate is 115200.

• AT commands have to be capitalized, and must end with a new line (CR LF).

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 3. Basic AT Commands
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3. Basic AT Commands
3.1. Overview
Commands Description

AT Tests AT startup.

AT+RST Restarts the module.

AT+GMR Checks version information.

AT+GSLP Enters Deep-sleep mode.

ATE Configures echoing of AT commands.

AT+RESTORE Restores the factory default settings of the module.

AT+UART_CUR The current UART configuration.

AT+UART_DEF The default UART configuration, saved in flash.

AT+SLEEP Configures the sleep modes.

AT+WAKEUPGPIO Configures a GPIO to wake ESP8266 up from Light-sleep mode.

AT+RFPOWER Sets the maximum value of the RF TX Power.

AT+RFVDD Sets the RF TX Power according to VDD33.

AT+SYSRAM Checks the available RAM size.

AT+SYSADC Checks the ADC value.

AT+SYSIOSETCFG Sets configuration of IO pins.

AT+SYSIOGETCFG Gets configuration of IO pins.

AT+SYSGPIODIR Configures the direction of GPIO.

AT+SYSGPIOWRITE Configures the GPIO output level

AT+SYSGPIOREAD Checks the GPIO input level.

AT+SYSMSG_CUR Sets current system messages.

AT+SYSMSG_DEF Sets default system messages.

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3.2. Commands
3.2.1. AT—Tests AT Startup

Execute Command AT

Response OK

Parameters -

3.2.2. AT+RST—Restarts the Module

Execute Command AT+RST

Response OK

Parameters -

3.2.3. AT+GMR—Checks Version Information

Execute Command AT+GMR

<AT version info>

<SDK version info>

Response <compile time>

OK

• <AT version info>: information about the AT version.

Parameters • <SDK version info>: information about the SDK version.

• <compile time>: the duration of time for compiling the BIN.

3.2.4. AT+GSLP—Enters Deep-sleep Mode

Set Command AT+GSLP=<time>

<time>

Response
OK

<time>: the duration of ESP8266’s sleep. Unit: ms.

Parameters ESP8266 will wake up after Deep-sleep for as many milliseconds (ms) as <time>
indicates.

A minor adjustment has to be made before the module enter the Deep-sleep mode, i.e.,
Note
connecting XPD_DCDC to EXT_RSTB via a 0-ohm resistor.

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 3. Basic AT Commands
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3.2.5. ATE—AT Commands Echoing

Execute Command ATE

Response OK

• ATE0: Switches echo off.

Parameters
• ATE1: Switches echo on.

This command ATE is used to trigger command echo. It means that entered commands
can be echoed back to the sender when ATE command is used. Two parameters are
Note
possible. The command returns OK in normal cases and ERROR when a parameter other
than 0 or 1 was specified.

3.2.6. AT+RESTORE—Restores the Factory Default Settings

Execute Command AT+RESTORE

Response OK

The execution of this command will reset all parameters saved in flash, and restore the
Note factory default settings of the module. The chip will be restarted when this command is
executed.

3.2.7. AT+UART_CUR—Current UART Configuration; Not Saved in the Flash

Set Command:
Query Command:
Command
AT+UART_CUR=<baudrate>,<databits>,<stop
AT+UART_CUR?
bits>,<parity>,<flow control>

+UART_CUR:<baudrate>,<databits>,<stop
Response bits>,<parity>,<flow control>
OK
OK

Command AT+UART_CUR? will return the

actual value of UART configuration
parameters, which may have allowable
errors compared with the set value
Note because of the clock division. -
For example, if the UART baud rate is set
as 115200, the baud rate returned by
using command AT+UART_CUR? could be
115273.

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 3. Basic AT Commands
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• <baudrate>: UART baud rate

• <databits>: data bits

‣ 5: 5-bit data
‣ 6: 6-bit data
‣ 7: 7-bit data
‣ 8: 8-bit data
• <stopbits>: stop bits

‣ 1: 1-bit stop bit

‣ 2: 1.5-bit stop bit
Parameters ‣ 3: 2-bit stop bit
• <parity>: parity bit

‣ 0: None
‣ 1: Odd
‣ 2: Even
• <flow control>: flow control

‣ 0: flow control is not enabled

‣ 1: enable RTS
‣ 2: enable CTS
‣ 3: enable both RTS and CTS

1. The configuration changes will NOT be saved in the flash.

2. The use of flow control requires the support of hardware:
Notes ‣ MTCK is UART0 CTS
‣ MTDO is UART0 RTS
3. The range of baud rates supported: 110~115200*40.

Example AT+UART_CUR=115200,8,1,0,3

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3.2.8. AT+UART_DEF—Default UART Configuration; Saved in the Flash

Set Command:
Query Command:
Command
AT+UART_DEF=<baudrate>,<databits>,<stopbits>
AT+UART_DEF?
,<parity>,<flow control>

+UART_DEF:<baudrate>,<databits>,<stopbits>,<
Response parity>,<flow control>
OK
OK

• <baudrate>: UART baud rate

• <databits>: data bits

‣ 5: 5-bit data
‣ 6: 6-bit data
‣ 7: 7-bit data
‣ 8: 8-bit data
• <stopbits>: stop bits

‣ 1: 1-bit stop bit

‣ 2: 1.5-bit stop bit
Parameter ‣ 3: 2-bit stop bit
• <parity>: parity bit

‣ 0: None
‣ 1: Odd
‣ 2: Even
• <flow control>: flow control

‣ 0: flow control is not enabled

‣ 1: enable RTS
‣ 2: enable CTS
‣ 3: enable both RTS and CTS

1. The configuration changes will be saved in the user parameter area in the flash, and will still be valid
when the chip is powered on again.
2. The use of flow control requires the support of hardware:
Notes
‣ MTCK is UART0 CTS
‣ MTDO is UART0 RTS
3. The range of baud rates supported: 110~115200*40.

Example AT+UART_DEF=115200,8,1,0,3

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3.2.9. AT+SLEEP—Configures the Sleep Modes

Query Command: Set Command:

Command
AT+SLEEP? AT+SLEEP=<sleep mode>

+SLEEP:<sleep mode>

Response OK
OK

<sleep mode>:

Parameter ‣ 0: disables sleep mode

‣ 1: Light-sleep mode
‣ 2: Modem-sleep mode

Notes This command can only be used in Station mode. Modem-sleep is the default sleep mode.

Example AT+SLEEP=0

3.2.10. AT+WAKEUPGPIO—Configures a GPIO to Wake ESP8266 up from Light-sleep Mode

Command AT+WAKEUPGPIO=<enable>,<trigger_GPIO>,<trigger_level>[,<awake_GPIO>,<awake_level>]

Response OK

• <enable>

‣ 0: ESP8266 can NOT be woken up from light-sleep by GPIO.

‣ 1: ESP8266 can be woken up from light-sleep by GPIO.

• <trigger_GPIO>

‣ Sets the GPIO to wake ESP8266 up; range of value: [0, 15].
• <trigger_level>

‣ 0: The GPIO wakes up ESP8266 on low level.

Parameter
‣ 1: The GPIO wakes up ESP8266 on high level.
• [<awake_GPIO>]

‣ Optional; this parameter is used to set a GPIO as a flag of ESP8266’s being awoken form
Light-sleep; range of value: [0, 15].
• [<awake_level>]

‣ Optional;

‣ 0: The GPIO is set to be low level after the wakeup process.

‣ 1: The GPIO is set to be high level after the wakeup process.

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• Since the system needs some time to wake up from light sleep, it is suggested that wait at
least 5ms before sending next AT command.
• The value of <trigger_GPIO> and <awake_GPIO> in the command should not be the same.
Notes • After being woken up by <trigger_GPIO> from Light-sleep, when the ESP8266 attempts to
sleep again, it will check the status of the <trigger_GPIO>:
‣ if it is still in the wakeup status, the EP8266 will enter Modem-sleep mode instead;
‣ if it is NOT in the wakeup status, the ESP8266 will enter Light-sleep mode.

• Set ESP8266 to be woken from Light-sleep, when GPIO0 is on low level:

AT+WAKEUPGPIO=1,0,0

• Set ESP8266 to be woken from Light-sleep, when GPIO0 is on high level. After the waking-
Example up, GPIO13 is set to high level.

AT+WAKEUPGPIO=1,0,1,13,1

• Disable the function that ESP8266 can be woken up from Light-sleep by a GPIO.

AT+WAKEUPGPIO=0

3.2.11. AT+RFPOWER—Sets the Maximum Value of RF TX Power

Set Command AT+RFPOWER=<TX Power>

Response OK

Parameter <TX Power>: the maximum value of RF TX power; range: [0, 82]; unit: 0.25 dBm.

This command sets the maximum value of ESP8266 RF TX power; it is not precise. The actual
Note
value could be smaller than the set value.

Example AT+RFPOWER=50

3.2.12. AT+RFVDD—Sets RF TX Power According to VDD33

Query Command:
Set Command: Execute Command:
AT+RFVDD?

Command AT+RFVDD=<VDD33>
AT+RFVDD

Function: Checks the

Function: Sets the RF TX Function: Automatically sets the RF TX
value of ESP8266
Power according to <VDD33>. Power.
VDD33.

+RFVDD:<VDD33>
Response OK OK
OK

<VDD33>: power voltage <VDD33>: power voltage of

Parameter of ESP8266 VDD33; ESP8266 VDD33 ; range: -
unit: 1/1024 V. [1900, 3300].

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The command should

only be used when
TOUT pin has to be TOUT pin has to be suspended in
Note -
suspended, or else the order to measure VDD33.
returned value would be
invalid.

Example AT+RFVDD=2800

3.2.13. AT+SYSRAM—Checks the Remaining Space of RAM

Query Command AT+SYSRAM?

+SYSRAM:<remaining RAM size>

Response
OK

Parameter <remaining RAM size>: remaining space of RAM, unit: byte.

3.2.14. AT+SYSADC—Checks the Value of ADC

Query Command AT+SYSADC?

+SYSADC:<ADC>
Response
OK

Parameter <ADC>: the value of ADC; unit: 1/1024V.

3.2.15. AT+SYSIOSETCFG—Configures IO Working Mode

Set Command AT+SYSIOSETCFG=<pin>,<mode>,<pull-up>

Response OK

• <pin>: number of an IO pin

• <mode>: the working mode of the IO pin

Parameter • <pull-up>

‣ 0: disable the pull-up

‣ 1: enable the pull-up of the IO pin

Note Please refer to ESP8266 Pin List for uses of AT+SYSIO-related commands.

Example AT+SYSIOSETCFG=12,3,1 //Set GPIO12 to work as a GPIO

3.2.16. AT+SYSIOGETCFG—Checks the Working Modes of IO Pins

Set Command AT+SYSIOGETCFG=<pin>

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+SYSIOGETCFG:<pin>,<mode>,<pull-up>
Response
OK

• <pin>: number of an IO pin

• <mode>: the working mode of the IO pin

Parameter • <pull-up>

‣ 0: disable the pull-up

‣ 1: enable the pull-up of the IO pin

Note Please refer to ESP8266 Pin List for uses of AT+SYSIO-related commands.

3.2.17. AT+SYSGPIODIR—Configures the Direction of a GPIO

Set Command AT+SYSGPIODIR=<pin>,<dir>

• If the configuration is successful, the command will return:

OK

Response • If the IO pin is not in GPIO mode, the command will return:

NOT GPIO MODE!

ERROR

• <pin>: GPIO pin number

• <dir>:

Parameter
‣ 0: sets the GPIO as an input

‣ 1: sets the GPIO as an output

Note Please refer to ESP8266 Pin List for uses of AT+SYSGPIO-related commands.

AT+SYSIOSETCFG=12,3,1 //Set GPIO12 to work as a GPIO

Example
AT+SYSGPIODIR=12,0 //Set GPIO12 to work as an input

3.2.18. AT+SYSGPIOWRITE—Configures the Output Level of a GPIO

Set Command AT+SYSGPIOWRITE=<pin>,<level>

• If the configuration is successful, the command will return:

OK

Response • If the IO pin is not in output mode, the command will return:

NOT OUTPUT!

ERROR

• <pin>: GPIO pin number

• <level>:

Parameter
‣ 0: low level

‣ 1: high level

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Note Please refer to ESP8266 Pin List for uses of AT+SYSGPIO-related commands.

AT+SYSIOSETCFG=12,3,1 //Set GPIO12 to work as a GPIO

Example AT+SYSGPIODIR=12,1 //Set GPIO12 to work as an output

AT+SYSGPIOWRITE=12,1 //Set GPIO12 to output high level

3.2.19. AT+SYSGPIOREAD—Reads the GPIO Input Level

Set Command AT+SYSGPIOREAD=<pin>

• If the configuration is successful, the command returns:

+SYSGPIOREAD:<pin>,<dir>,<level>

OK

Response
• If the IO pin is not in GPIO mode, the command will return:

NOT GPIO MODE!

ERROR

• <pin>: GPIO pin number

• <dir>:

‣ 0: sets the GPIO as an input

Parameter ‣ 1: sets the GPIO as an output

• <level>:

‣ 0: low level

‣ 1: high level

Note Please refer to ESP8266 Pin List for uses of AT+SYSGPIO-related commands.

AT+SYSIOSETCFG=12,3,1 //Set GPIO12 to work as a GPIO

Example AT+SYSGPIODIR=12,0 //Set GPIO12 to work as an input

AT+SYSGPIOREAD=12

3.2.20. AT+SYSMSG_CUR—Set Current System Messages

Set Command AT+SYSMSG_CUR=<n>

Response OK

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<n>:

• bit0: configure the message of quitting WiFi-UART passthrough transmission

‣ if the bit0 is 0, there is no message when quitting WiFi-UART passthrough transmission;

default is 0

‣ if the bit0 is 1, when quitting WiFi-UART passthrough transmission, it will prompt the
message +QUITT // Quit transparent transmission

• bit1: configure the message of establishing a network transmission

Parameter
‣ if the bit1 is 0, when a network connection is established, it will prompt the message
<Link_ID>,CONNECT; default is 0

‣ if the bit1 is 1, when establishing a network connection, it will prompt the message
+LINK_CONN:<status_type>,<link_id>,"UDP/TCP/SSL",<c/s>,<remote_ip>,
<remote_port>,<local_port>;

- <status_type> : 0 - the connection is established successfully;

1 - fail to establish the connection

- <c/s> : 0 - the ESP works as a client; 1 - the ESP works as a server

Note The configuration changes will NOT be saved in the flash.

Example AT+SYSMSG_CUR=3

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3.2.21. AT+SYSMSG_DEF—Set Default System Messages

Set Command AT+SYSMSG_DEF=<n>

Response OK

<n>:

• bit0: configure the message of quitting WiFi-UART passthrough transmission

‣ if the bit0 is 0, there is no message when quitting WiFi-UART passthrough transmission;

default is 0

‣ if the bit0 is 1, when quitting WiFi-UART passthrough transmission, it will prompt the
message +QUITT // Quit transparent transmission

• bit1: configure the message of establishing a network transmission

Parameter ‣ if the bit1 is 0, when a network connection is established, it will prompt the message
<Link_ID>,CONNECT; default is 0

‣ if the bit1 is 1, when establishing a network connection, it will prompt the message
+LINK_CONN:<status_type>,<link_id>,"UDP/TCP/SSL",<c/s>,<remote_ip>,
<remote_port>,<local_port>;

- <status_type> : 0 - the connection is established successfully;

1 - fail to establish the connection

- <c/s> : 0 - the ESP works as a client; 1 - the ESP works as a server

Note The configuration changes will be saved in the flash user parameter area.

Example AT+SYSMSG_DEF=3

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4. Wi-Fi AT Commands
4.1. Overview
Commands Description

AT+CWMODE_CUR Sets the Wi-Fi mode (Station/AP/Station+AP); configuration not saved in the flash.

AT+CWMODE_DEF Sets the default Wi-Fi mode (Station/AP/Station+AP); configuration saved in the flash.

AT+CWJAP_CUR Connects to an AP; configuration not saved in the flash.

AT+CWJAP_DEF Connects to an AP; configuration saved in the flash.

AT+CWLAPOPT Sets the configuration of command AT+CWLAP.

AT+CWLAP Lists available APs.

AT+CWQAP Disconnects from an AP.

AT+CWSAP_CUR Sets the current configuration of the ESP8266 SoftAP; configuration not saved in the flash.

AT+CWSAP_DEF Sets the configuration of the ESP8266 SoftAP; configuration saved in the flash.

AT+CWLIF Gets the Station IP to which the ESP8266 SoftAP is connected.

AT+CWDHCP_CUR Enables/Disables DHCP; configuration not saved in the flash.

AT+CWDHCP_DEF Enable/Disable DHCP; configuration saved in the flash.

AT+CWDHCPS_CUR Sets the IP range of the DHCP server; configuration not saved in the flash.

AT+CWDHCPS_DEF Sets the IP range of the DHCP server; configuration saved in the flash.

AT+CWAUTOCONN Connects to an AP automatically on power-up.

AT+CIPSTAMAC_CUR Sets the MAC address of the ESP8266 Station; configuration not saved in the flash.

AT+CIPSTAMAC_DEF Sets the MAC address of ESP8266 station; configuration saved in the flash.

AT+CIPAPMAC_CUR Sets the MAC address of the ESP8266 SoftAP; configuration not saved in the flash.

AT+CIPAPMAC_DEF Sets the MAC address of the ESP8266 SoftAP; configuration saved in the flash.

AT+CIPSTA_CUR Sets the IP address of the ESP8266 Station; configuration not saved in the flash.

AT+CIPSTA_DEF Sets the IP address of the ESP8266 Station; configuration saved in the flash.

AT+CIPAP_CUR Sets the IP address of ESP8266 SoftAP; configuration not saved in the flash.

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AT+CIPAP_DEF Sets the IP address of ESP8266 SoftAP; configuration saved in the flash.

AT+CWSTARTSMART Starts SmartConfig.

AT+CWSTOPSMART Stops SmartConfig.

AT+CWSTARTDISCOVER Enables the mode that ESP8266 can be found by WeChat.

AT+CWSTOPDISCOVER Disables the mode that ESP8266 can be found by WeChat.

AT+WPS Sets the WPS function.

AT+MDNS Sets the MDNS function.

AT+CWHOSTNAME Sets the host name of the ESP8266 Station.

AT+CWCOUNTRY_CUR Sets current WiFi country code

AT+CWCOUNTRY_DEF Sets default WiFi country code

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4.2. Commands
4.2.1. AT+CWMODE_CUR—Sets the Current Wi-Fi mode; Configuration Not Saved in the Flash

Query Command: Set Command:

Test Command: AT+CWMODE_CUR?
AT+CWMODE_CUR=<mode>

Commands
AT+CWMODE_CUR=? Function: to query the current Wi-Fi Function: to set the current Wi-Fi
mode of ESP8266. mode of ESP8266.

+CWMODE_CUR:<mode> +CWMODE_CUR:<mode>

Response OK
OK OK

<mode>:

Parameters ‣ 1: Station mode

‣ 2: SoftAP mode
‣ 3: SoftAP+Station mode

Note The configuration changes will NOT be saved in the flash.

Example AT+CWMODE_CUR=3

4.2.2. AT+CWMODE_DEF—Sets the Default Wi-Fi mode; Configuration Saved in the Flash

Query Command: Set Command:

Test Command: AT+CWMODE_DEF?
AT+CWMODE_DEF=<mode>

Commands
AT+CWMODE_DEF=? Function: to query the current Wi-Fi Function: to set the current Wi-Fi
mode of ESP8266. mode of ESP8266.

+CWMODE_DEF:<mode> +CWMODE_DEF:<mode>

Response OK
OK OK

<mode>:

Parameters ‣ 1: Station mode

‣ 2: SoftAP mode
‣ 3: SoftAP+Station mode

Note The configuration changes will be saved in the system parameter area in the flash.

Example AT+CWMODE_DEF=3

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4.2.3. AT+CWJAP_CUR—Connects to an AP; Configuration Not Saved in the Flash

Set Command:
Query Command:
AT+CWJAP_CUR=<ssid>,<pwd>,[<bssid>]
Commands AT+CWJAP_CUR?
[,<pci_en>]
Function: to query the AP to which the ESP8266
Function: to set the AP to which the ESP8266
Station is already connected.
Station needs to be connected.

OK
+CWJAP_CUR:<ssid>,<bssid>,<channel>,<rssi>
or
Response
OK +CWJAP_CUR:<error code>
FAIL

• <ssid>: the SSID of the target AP.

• <pwd>: password, MAX: 64-byte ASCII.

• [<bssid>]: optional parameter, the target AP’s

MAC address, used when multiple APs have the
same SSID.
• [<pci_en>]: optional parameter, disable the
connection to WEP or OPEN AP, and can be
used for PCI authentication.
<ssid>: a string parameter showing the SSID of
Parameters
the target AP. • <error code>: (for reference only)
‣ 1: connection timeout.
‣ 2: wrong password.
‣ 3: cannot find the target AP.
‣ 4: connection failed.
This command requires Station mode to be enabled.
Escape character syntax is needed if SSID or
password contains any special characters, such as ,
or ” or \.

Note The configuration changes will NOT be saved in the flash.

AT+CWJAP_CUR="abc","0123456789"

For example, if the target AP’s SSID is "ab\,c" and the password is "0123456789"\", the command is
as follows:

Examples
AT+CWJAP_CUR="ab\\\,c","0123456789\"\\"

If multiple APs have the same SSID as "abc", the target AP can be found by BSSID:

AT+CWJAP_CUR="abc","0123456789","ca:d7:19:d8:a6:44"

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4.2.4. AT+CWJAP_DEF—Connects to an AP; Configuration Saved in the Flash

Set Command:
Query Command:
AT+CWJAP_DEF=<ssid>,<pwd>,[<bssid>]
Commands AT+CWJAP_DEF?
[,<pci_en>]
Function: to query the AP to which the ESP8266
Function: to set the AP to which the ESP8266
Station is already connected.
Station needs to be connected.

OK
+CWJAP_DEF:<ssid>,<bssid>,<channel>,<rssi>
or
Response
OK +CWJAP_DEF:<error code>
FAIL

• <ssid>: the SSID of the target AP, MAX: 32 bytes.

• <pwd>: password, MAX: 64-byte ASCII.

• [<bssid>]: optional parameter, the target AP’s

MAC address, used when multiple APs have the
same SSID.
• [<pci_en>]: optional parameter, disable the
connection to WEP or OPEN AP, and can be
used for PCI authentication.
<ssid>: a string parameter showing the SSID of
Parameters
the target AP. • <error code>: (for reference only)
‣ 1: connection timeout.
‣ 2: wrong password.
‣ 3: cannot find the target AP.
‣ 4: connection failed.
This command requires Station mode to be enabled.
Escape character syntax is needed if SSID or
password contains any special characters, such as ,
or ” or \.

Note The configuration changes will be saved in the system parameter area in the flash.

AT+CWJAP_DEF="abc","0123456789"

For example, if the target AP’s SSID is "ab\,c" and the password is "0123456789"\", the command is
as follows:

Examples
AT+CWJAP_DEF="ab\\\,c","0123456789\"\\"

If multiple APs have the same SSID as "abc", the target AP can be found by BSSID:

AT+CWJAP_DEF="abc","0123456789","ca:d7:19:d8:a6:44"

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4.2.5. AT+CWLAPOPT—Sets the Configuration for the Command AT+CWLAP

Set Command AT+CWLAPOPT=<sort_enable>,<mask>

OK
Response or

ERROR

• <sort_enable>: determines whether the result of command AT+CWLAP will be listed according to
RSSI:
‣ 0: the result is ordered according to RSSI.
‣ 1: the result is not ordered according to RSSI.
• <mask>: determines the parameters shown in the result of AT+CWLAP; 0 means not showing the
parameter corresponding to the bit, and 1 means showing it.
‣ bit 0: determines whether <ecn> will be shown in the result of AT+CWLAP.
Parameters ‣ bit 1: determines whether <ssid> will be shown in the result of AT+CWLAP.
‣ bit 2: determines whether <rssi> will be shown in the result of AT+CWLAP.
‣ bit 3: determines whether <mac> will be shown in the result of AT+CWLAP.
‣ bit 4: determines whether <ch> will be shown in the result of AT+CWLAP.
‣ bit 5: determines whether <freq offset> will be shown in the result of AT+CWLAP.

‣ bit 6: determines whether <freq calibration> will be shown in the result of AT+CWLAP.
‣ bit 7: determines whether <pairwise_cipher> will be shown in the result of AT+CWLAP.

‣ bit 8: determines whether <group_cipher> will be shown in the result of AT+CWLAP.

‣ bit 9: determines whether <bgn> will be shown in the result of AT+CWLAP.

‣ bit 10: determines whether <wps> will be shown in the result of AT+CWLAP.

AT+CWLAPOPT=1,2047

The first parameter is 1, meaning that the result of the command AT+CWLAP will be ordered
Example according to RSSI;

The second parameter is 2047, namely 0x7FF, meaning that the corresponding bits of <mask> are
set to 1. All parameters will be shown in the result of AT+CWLAP.

4.2.6. AT+CWLAP—Lists Available APs

Set Command:
Execute Command:
AT+CWLAP[=<ssid>,<mac>,<channel>,<scan_
Commands type>,<scan_time_min>,<scan_time_max>] AT+CWLAP

Function: to query the APs with specific SSID Function: to list all available APs.
and MAC on a specific channel.

+CWLAP:<ecn>,<ssid>,<rssi>,<mac>,<chann
+CWLAP:<ecn>,<ssid>,<rssi>,<mac>,<channel>,<
el>,<freq offset>,<freq
freq offset>, <freq cali>,<pairwise_cipher>,
Response cali>,<pairwise_cipher>,
<group_cipher>,<bgn>,<wps>

<group_cipher>,<bgn>,<wps>

OK
OK

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• [<scan_type>]: optional parameter

‣ 0: active scan

‣ 1: passive scan

• [<scan_time_min>] : optional parameter, unit: ms, range: [0,1500]

‣ For active scan mode, <scan_time_min> is the minimum scan time for each channel, default
is 0
‣ For passive scan mode, <scan_time_min> is meaningless, can be omitted

• [<scan_time_max>] : optional parameter, unit: ms, range: [0,1500]

‣ For active scan mode, <scan_time_max> is the maximum scan time for each channel; if it is
set to be 0, a default value, 120ms will be used.
‣ For passive scan mode, <scan_time_max> is the scan time for each channel, default is 360ms

• <ecn>: encryption method.

‣ 0: OPEN
‣ 1: WEP
‣ 2: WPA_PSK
‣ 3: WPA2_PSK
‣ 4: WPA_WPA2_PSK
‣ 5: WPA2_Enterprise (AT can NOT connect to WPA2_Enterprise AP for now.)
• <ssid>: string parameter, SSID of the AP.

• <rssi>: signal strength.

Parameters
• <mac>: string parameter, MAC address of the AP.

• <channel>: channel number

• <freq offset>: frequency offset of AP; unit: KHz. The value of ppm is <freq offset>/2.4.

• <freq calibration>: calibration for frequency offset.

• <pairwise_cipher>:
‣ 0：CIPHER_NONE
‣ 1：CIPHER_WEP40
‣ 2：CIPHER_WEP104
‣ 3：CIPHER_TKIP
‣ 4：CIPHER_CCMP
‣ 5：CIPHER_TKIP_CCMP
‣ 6：CIPHER_UNKNOWN
• <group_cipher>: definitions of cipher types are same as <pairwise_cipher>
• <bgn>:
‣ bit0 is for 802.11b mode; bit1 is for 802.11g mode; bit2 is for 802.11n mode;
‣ if the value of the bit is 1, the corresponding 802.11 mode is enabled; if the bit value is 0, the
mode is disabled.
• <wps>：0, WPS is disabled; 1, WPS is enabled

AT+CWLAP="Wi-Fi","ca:d7:19:d8:a6:44",6

or search for APs with a designated SSID:

Examples AT+CWLAP="Wi-Fi"

or enable passive scan:

AT+CWLAP=,,,1,,

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4.2.7. AT+CWQAP—Disconnects from the AP

Execute Command AT+CWQAP

Response OK

Parameters -

4.2.8. AT+CWSAP_CUR—Configures the ESP8266 SoftAP; Configuration Not Saved in the Flash

Query Command: Set Command:

AT+CWSAP_CUR?
AT+CWSAP_CUR=<ssid>,<pwd>,<chl>,<ecn>[,
Commands
<max conn>][,<ssid hidden>]

Function: to obtain the configuration

parameters of the ESP8266 SoftAP. Function: to configure the ESP8266 SoftAP.

OK

+CWSAP_CUR:<ssid>,<pwd>,<chl>,<ecn>,<m
Response or

ax conn>,<ssid hidden>
ERROR

• <ssid>: string parameter, SSID of AP.

• <pwd>: string parameter, length of
password: 8 ~ 64 bytes ASCII.
• <chl>: channel ID.
• <ecn>: encryption method; WEP is not
supported.
‣ 0: OPEN
‣ 2: WPA_PSK ⚠ Notice:
Parameters ‣ 3: WPA2_PSK
This command is only available when SoftAP
‣ 4: WPA_WPA2_PSK is active.
• [<max conn>] (optional): maximum
number of Stations to which ESP8266
SoftAP can be connected; within the
range of [1, 8].
• [<ssid hidden>] (optional):
‣ 0: SSID is broadcasted. (the default
setting)
‣ 1: SSID is not broadcasted.

Note The configuration changes will NOT be saved in the flash.

Example AT+CWSAP_CUR="ESP8266","1234567890",5,3

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4.2.9. AT+CWSAP_DEF—Configures the ESP8266 SoftAP; Configuration Saved in the Flash

Query Command: Set Command:

Commands AT+CWSAP_DEF?
AT+CWSAP_DEF=<ssid>,<pwd>,<chl>,<ecn>[,
Function: to obtain the configuration <max conn>][,<ssid hidden>]

parameters of the ESP8266 SoftAP. Function: to list all available APs.

OK

+CWSAP_DEF:<ssid>,<pwd>,<chl>,<ecn>,<m
Response or

ax conn>,<ssid hidden>
ERROR

• <ssid>: string parameter, SSID of AP.

• <pwd>: string parameter, length of
password: 8 ~ 64 bytes ASCII.
• <chl>: channel ID.
• <ecn>: encryption method; WEP is not
supported.
‣ 0: OPEN
The same as above.
‣ 2: WPA_PSK
Parameters ‣ 3: WPA2_PSK ⚠ Notice:
‣ 4: WPA_WPA2_PSK
This command is only available when SoftAP
• [<max conn>] (optional): maximum is active.
number of Stations to which ESP8266
SoftAP can be connected; within the
range of [1, 8].
• [<ssid hidden>] (optional):
‣ 0: SSID is broadcasted. (the default
setting)
‣ 1: SSID is not broadcasted.

Note The configuration changes will be saved in the flash system parameter area.

Example AT+CWSAP_DEF="ESP8266","1234567890",5,3

4.2.10. AT+CWLIF—IP of Stations to Which the ESP8266 SoftAP is Connected

Execute Command AT+CWLIF

<ip addr>,<mac>

Response
OK

• <ip addr>: IP address of Stations to which ESP8266 SoftAP is connected.

Parameters
• <mac>: MAC address of Stations to which ESP8266 SoftAP is connected.

Note This command cannot get a static IP. It only works when both DHCPs of the ESP8266
SoftAP, and of the Station to which ESP8266 is connected, are enabled.

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4.2.11. AT+CWDHCP_CUR—Enables/Disables DHCP; Configuration Not Saved in the Flash

Set Command:
Query Command:
Commands AT+CWDHCP_CUR=<<mode>,<en>
AT+CWDHCP_CUR?
Function: to enable/disable DHCP.

Response DHCP disabled or enabled now? OK

• <mode>:
• Bit0:
‣ 0: Sets ESP8266 SoftAP
‣ 0: SoftAP DHCP is disabled.
‣ 1: Sets ESP8266 Station
‣ 1: SoftAP DHCP is enabled.
Parameters ‣ 2: Sets both SoftAP and Station
• Bit1:
• <en>:
‣ 0: Station DHCP is disabled.
‣ 0: Disables DHCP
‣ 1: Station DHCP is enabled.
‣ 1: Enables DHCP

• The configuration changes will not be saved in flash.

• This Set Command interacts with static-IP-related AT commands (AT+CIPSTA-related and

Notes AT+CIPA-related commands):
‣ If DHCP is enabled, static IP will be disabled;
‣ If static IP is enabled, DHCP will be disabled;
‣ Whether it is DHCP or static IP that is enabled depends on the last configuration.

Example AT+CWDHCP_CUR=0,1

4.2.12. AT+CWDHCP_DEF—Enables/Disables DHCP; Configuration Saved in the Flash

Set Command:
Query Command:
Commands AT+CWDHCP_DEF=<<mode>,<en>
AT+CWDHCP_DEF?
Function: to enable/disable DHCP.

Response DHCP disabled or enabled now? OK

• <mode>:
• Bit0:
‣ 0: Sets ESP8266 SoftAP
‣ 0: SoftAP DHCP is disabled.
‣ 1: Sets ESP8266 Station
‣ 1: SoftAP DHCP is enabled.
Parameters ‣ 2: Sets both SoftAP and Station
• Bit1:
• <en>:
‣ 0: Station DHCP is disabled.
‣ 0: Disables DHCP
‣ 1: Station DHCP is enabled.
‣ 1: Enables DHCP

• The configuration changes will be stored in the user parameter area in the flash.

• This Set Command interacts with static-IP-related AT commands (AT+CIPSTA-related and

Notes AT+CIPA-related commands):
‣ If DHCP is enabled, static IP will be disabled;
‣ If static IP is enabled, DHCP will be disabled;
‣ Whether it is DHCP or static IP that is enabled depends on the last configuration.

Example AT+CWDHCP_DEF=0,1

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4.2.13. AT+CWDHCPS_CUR—Sets the IP Address Allocated by ESP8266 SoftAP DHCP;

Configuration Not Saved in Flash

Set Command:

Query Command: AT+CWDHCPS_CUR=<enable>,<lease

Commands time>,<start IP>,<end IP>
AT+CWDHCPS_CUR?
Function: sets the IP address range of the
ESP8266 SoftAP DHCP server.

+CWDHCPS_CUR=<lease time>,<start
Response OK
IP>,<end IP>

• <enable>:

‣ 0: Disable the settings and use the default IP range.

‣ 1: Enable setting the IP range, and the parameters below have to be set.
Parameters • <lease time>: lease time; unit: minute; range [1, 2880].

• <start IP>: start IP of the IP range that can be obtained from ESP8266 SoftAP DHCP
server.
• <end IP>: end IP of the IP range that can be obtained from ESP8266 SoftAP DHCP server.

• The configuration changes will NOT be saved in the flash.

Notes • This AT command is enabled when ESP8266 runs as SoftAP, and when DHCP is enabled.
The IP address should be in the same network segment as the IP address of ESP8266
SoftAP.

AT+CWDHCPS_CUR=1,3,"192.168.4.10","192.168.4.15"

Examples or

AT+CWDHCPS_CUR=0 //Disable the settings and use the default IP range.

4.2.14. AT+CWDHCPS_DEF—Sets the IP Address Allocated by ESP8266 SoftAP DHCP;

Configuration Saved in Flash

Set Command:

Query Command: AT+CWDHCPS_DEF=<enable>,<lease time>,<start

Commands IP>,<end IP>
AT+CWDHCPS_DEF?
Function: sets the IP address range of the
ESP8266 SoftAP DHCP server.

Response +CWDHCPS_DEF=<lease time>,<start

OK
IP>,<end IP>

• <enable>:

‣ 0: Disable the settings and use the default IP range.

‣ 1: Enable setting the IP range, and the parameters below have to be set.
Parameters • <lease time>: lease time; unit: minute; range [1, 2880].

• <start IP>: start IP of the IP range that can be obtained from ESP8266 SoftAP DHCP
server.
• <end IP>: end IP of the IP range that can be obtained from ESP8266 SoftAP DHCP server.

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• The configuration changes will be stored in the user parameter area in the flash.

Notes • This AT command is enabled when ESP8266 runs as SoftAP, and when DHCP is enabled.
The IP address should be in the same network segment as the IP address of ESP8266
SoftAP.

AT+CWDHCPS_DEF=1,3,"192.168.4.10","192.168.4.15"

Examples or

AT+CWDHCPS_DEF=0 //Disable the settings and use the default IP range.

4.2.15. AT+CWAUTOCONN—Auto-Connects to the AP or Not

Set Command AT+CWAUTOCONN=<enable>

Response OK

<enable>:

Parameters ‣ 0: does NOT auto-connect to AP on power-up.

‣ 1: connects to AP automatically on power-up.
The ESP8266 Station connects to the AP automatically on power-up by default.

Note The configuration changes will be saved in the system parameter area in the flash.

Example AT+CWAUTOCONN=1

4.2.16. AT+CIPSTAMAC_CUR—Sets the MAC Address of the ESP8266 Station; Configuration Not
Saved in the Flash

Set Command:
Query Command: AT+CIPSTAMAC_CUR=<mac>

Commands
AT+CIPSTAMAC_CUR? Function: to set the MAC address of the ESP8266
Station.

+CIPSTAMAC_CUR:<mac>

Response OK
OK

Parameters <mac>: string parameter, MAC address of the ESP8266 Station.

• The configuration changes will NOT be saved in the flash.

• The MAC address of ESP8266 SoftAP is different from that of the ESP8266 Station. Please
Notes make sure that you do not set the same MAC address for both of them.
• Bit 0 of the ESP8266 MAC address CANNOT be 1. For example, a MAC address can be
“18:…” but not “15:…”.

Example AT+CIPSTAMAC_CUR="18:fe:35:98:d3:7b"

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4.2.17. AT+CIPSTAMAC_DEF—Sets the MAC Address of the ESP8266 Station; Configuration Saved
in the Flash

Set Command:
Query Command: AT+CIPSTAMAC_DEF=<mac>

Commands
AT+CIPSTAMAC_DEF? Function: to set the MAC address of the ESP8266
Station.

+CIPSTAMAC_DEF:<mac>

Response OK
OK

Parameters <mac>: string parameter, MAC address of the ESP8266 Station.

• The configuration changes will be saved in the user parameter area in the flash.

• The MAC address of ESP8266 SoftAP is different from that of the ESP8266 Station. Please
Notes make sure that you do not set the same MAC address for both of them.
• Bit 0 of the ESP8266 MAC address CANNOT be 1. For example, a MAC address can be “18:
…” but not “15:…”.

Example AT+CIPSTAMAC_DEF="18:fe:35:98:d3:7b"

4.2.18. AT+CIPAPMAC_CUR—Sets the MAC Address of the ESP8266 SoftAP; Configuration Not
Saved in the Flash

Query Command: Set Command:

AT+CIPAPMAC_CUR? AT+CIPAPMAC_CUR=<mac>
Commands
Function: to obtain the MAC address of Function: to set the MAC address of the ESP8266
the ESP8266 SoftAP. SoftAP.

+CIPAPMAC_CUR:<mac>

Response OK
OK

Parameters <mac>: string parameter, MAC address of ESP8266 SoftAP.

• The configuration changes will NOT be saved the flash.

• The MAC address of ESP8266 SoftAP is different from that of the ESP8266 Station. Please
Notes make sure you do not set the same MAC address for both of them.
• Bit 0 of the ESP8266 MAC address CANNOT be 1. For example, a MAC address can be “18:
…” but not “15:…”.

Example AT+CIPAPMAC_CUR="1a:fe:36:97:d5:7b"

4.2.19. AT+CIPAPMAC_DEF—Sets the MAC Address of the ESP8266 SoftAP; Configuration Saved
in Flash

Query Command: Set Command:

Commands AT+CIPAPMAC_DEF? AT+CIPAPMAC_DEF=<mac>

Function: to obtain the MAC address of Function: to set the MAC address of the ESP8266
the ESP8266 SoftAP. SoftAP.

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+CIPAPMAC_DEF:<mac>

Response OK
OK

Parameters <mac>: string parameter, MAC address of ESP8266 SoftAP.

• The configuration changes will be saved in the user parameter area in the flash.

• The MAC address of ESP8266 SoftAP is different from that of the ESP8266 Station. Please
Notes make sure you do not set the same MAC address for both of them.
• Bit 0 of the ESP8266 MAC address CANNOT be 1. For example, a MAC address can be “18:
…” but not “15:…”.

Example AT+CIPAPMAC_DEF="1a:fe:36:97:d5:7b"

4.2.20. AT+CIPSTA_CUR—Sets the Current IP Address of the ESP8266 Station; Configuration Not
Saved in the Flash

Query Command: Set Command:

Commands AT+CIPSTA_CUR?
AT+CIPSTA_CUR=<ip>[,<gateway>,<netmask>]
Function: to obtain the current IP Function: to set the current IP address of the ESP8266
address of the ESP8266 Station. Station.

+CIPSTA_CUR:<ip>

+CIPSTA_CUR:<gateway>

Response OK
+CIPSTA_CUR:<netmask>

OK

⚠ Notice: • <ip>: string parameter, the IP address of the

ESP8266 Station.
Parameters Only when the ESP8266 Station is
• [<gateway>]: gateway.
connected to an AP can its IP address
be queried. • [<netmask>]: netmask.

• The configuration changes will NOT be saved in the flash.

• The Set Command interacts with DHCP-related AT commands (AT+CWDHCP-related commands):

Notes
‣ If static IP is enabled, DHCP will be disabled;
‣ If DHCP is enabled, static IP will be disabled;
‣ Whether it is DHCP or static IP that is enabled depends on the last configuration.

Example AT+CIPSTA_CUR="192.168.6.100","192.168.6.1","255.255.255.0"

4.2.21. AT+CIPSTA_DEF—Sets the Default IP Address of the ESP8266 Station; Configuration Saved
in the Flash

Query Command: Set Command:

AT+CIPSTA_DEF?
AT+CIPSTA_DEF=<ip>[,<gateway>,<netmask>]
Commands
Function: to obtain the default IP address Function: to set the default IP address of the ESP8266
of the ESP8266 Station. Station.

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+CIPSTA_DEF:<ip>

+CIPSTA_DEF:<gateway>

Response OK
+CIPSTA_DEF:<netmask>

OK

⚠ Notice: • <ip>: string parameter, the IP address of the

ESP8266 Station.
Parameters Only when the ESP8266 Station is
• [<gateway>]: gateway.
connected to an AP can its IP address
be queried. • [<netmask>]: netmask.

• The configuration changes will be saved in the user parameter area in the flash.

• The Set Command interacts with DHCP-related AT commands (AT+CWDHCP-related

Notes commands):
‣ If static IP is enabled, DHCP will be disabled;
‣ If DHCP is enabled, static IP will be disabled;
‣ Whether it is DHCP or static IP that is enabled depends on the last configuration.

Example AT+CIPSTA_DEF="192.168.6.100","192.168.6.1","255.255.255.0"

4.2.22. AT+CIPAP_CUR—Sets the IP Address of the ESP8266 SoftAP; Configuration Not Saved in
the Flash

Query Command: Set Command:

Commands AT+CIPAP_CUR? AT+CIPAP_CUR=<ip>[,<gateway>,<netmask>]

Function: to obtain the current IP address Function: to set the current IP address of the ESP8266
of the ESP8266 SoftAP. SoftAP.

+CIPAP_CUR:<ip>

+CIPAP_CUR:<gateway>

Response OK
+CIPAP_CUR:<netmask>

OK

• <ip>: string parameter, the IP address of the ESP8266 SoftAP.

Parameters • [<gateway>]: gateway.

• [<netmask>]: netmask.

• The configuration changes will not be saved in the flash.

• Currently, ESP8266 only supports class C IP addresses.

Notes • The Set Command interacts with DHCP-related AT commands (AT+CWDHCP-related commands):

‣ If static IP is enabled, DHCP will be disabled;

‣ If DHCP is enabled, static IP will be disabled;
‣ Whether it is DHCP or static IP that is enabled depends on the last configuration.

Example AT+CIPAP_CUR="192.168.5.1","192.168.5.1","255.255.255.0"

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4.2.23. AT+CIPAP_DEF—Sets the Default IP Address of the ESP8266 SoftAP; Configuration Saved
in the Flash

Query Command: Set Command:

Commands AT+CIPAP_DEF? AT+CIPAP_DEF=<ip>[,<gateway>,<netmask>]

Function: to obtain the default IP address Function: to set the default IP address of the ESP8266
of the ESP8266 SoftAP. SoftAP.

+CIPAP_DEF:<ip>

+CIPAP_DEF:<gateway>

Response OK
+CIPAP_DEF:<netmask>

OK

• <ip>: string parameter, the IP address of the ESP8266 SoftAP.

Parameters • [<gateway>]: gateway.

• [<netmask>]: netmask.

• The configuration changes will be saved in the user parameter area in the flash.

• Currently, ESP8266 only supports class C IP addresses.

Notes • The Set Command interacts with DHCP-related AT commands (AT+CWDHCP-related commands):

‣ If static IP is enabled, DHCP will be disabled;

‣ If DHCP is enabled, static IP will be disabled;
‣ Whether it is DHCP or static IP that is enabled depends on the last configuration.

Example AT+CIPAP_DEF="192.168.5.1","192.168.5.1","255.255.255.0"

4.2.24. AT+CWSTARTSMART—Starts SmartConfig

Execute Command:
AT+CWSTARTSMART
Set Command:
Commands AT+CWSTARTSMART=<type>

Function: to start SmartConfig. (The type

of SmartConfig is ESP-TOUCH + Function: to start SmartConfig of a designated type.
AirKiss.）

Response OK

<type>:

Parameters ‣ 1: ESP-TOUCH
‣ 2: AirKiss
‣ 3: ESP-TOUCH+AirKiss

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When smartconfig starts, it will prompt messages as below:

smartconfig type: <type> // AIRKISS or ESPTOUCH
smart get wifi info // got SSID and password
ssid:<AP's SSID>
Messages password:<AP's password>
// ESP8266 will try to connect to the AP
WIFI CONNECTED
WIFI GOT IP
smartconfig connected wifi // if the connection failed, it will prompt "smartconfig connect fail"

• For details on SmartConfig please see ESP-TOUCH User Guide.

• SmartConfig is only available in the ESP8266 Station mode.

• The message smart get wifi info means that SmartConfig has successfully acquired the AP
information. ESP8266 will try to connect to the target AP.
• Message smartconfig connected wifi is printed if the connection is successful. Use command
Notes AT+CWSTOPSMART to stop SmartConfig before running other commands. Please make sure that
you do not execute other commands during SmartConfig.
• Starting from AT_v1.0, SmartConfig can get protocol type (AirKiss or ESP-TOUCH) automatically
by command AT+CWSTARTSMART.
• Users can remove this function to reduce bin size and save memory by recompiling the at project,
refer to Section 1.1, and disable the #define CONFIG_AT_SMARTCONFIG_COMMAND_ENABLE in
user_config.h.

AT+CWMODE=1

Example
AT+CWSTARTSMART

4.2.25. AT+CWSTOPSMART—Stops SmartConfig

Execute Command AT+CWSTOPSMART

Response OK

Parameters -

Note Irrespective of whether SmartConfig succeeds or not, before executing any other AT commands,
please always call AT+CWSTOPSMART to release the internal memory taken up by SmartConfig.

Example AT+CWSTOPSMART

4.2.26. AT+CWSTARTDISCOVER—Enables the Mode that ESP8266 can be Found by WeChat

Set Command AT+CWSTARTDISCOVER=<WeChat number>,<dev_type>,<time>

Response OK

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• <WeChat number>: WeChat official account, which is to be obtained from WeChat.

• <dev_type>: the device type, which is to be obtained from WeChat.

• <time>: the interval of time for ESP8266 to send packets; range: 0 ~ 24x3600; unit: second.
Parameters
‣ 0: ESP8266 will not take the initiative to send packets; it only makes response to queries
from WeChat.
‣ Otherwise: the time interval for ESP8266 to send packets regularly in order to be detected by
WeChat on the same LAN.

• For details on detection function of WeChat, please refer to http://iot.weixin.qq.com.

Note • ESP8266 Station should connect to an AP and obtain an IP address first before this command
is used.

Example AT+CWSTARTDISCOVER="gh_9e2cff3dfa51","122475",10

4.2.27. AT+CWSTOPDISCOVER—Disables the Mode that ESP8266 can be Found by WeChat

Execute Command AT+CWSTOPDISCOVER

Response OK

Example AT+CWSTOPDISCOVER

4.2.28. AT+WPS—Enables the WPS Function

Set Command AT+WPS=<enable>

Response OK

<enable>:
Parameters
‣ 1: enables WPS/Wi-Fi Protected Setup
‣ 0: disables WPS

• WPS must be used when the ESP8266 Station is enabled.

Notes
• WPS does not support WEP/Wired-Equivalent Privacy encryption.

AT+CWMODE=1

Example
AT+WPS=1

4.2.29. AT+MDNS—Configures the MDNS Function

Set Command AT+MDNS=<enable>,<hostname>,<server_name>,<server_port>

OK

or
Response
opmode mismatch when mdns

ERROR

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• <enable>:

‣ 1: enables the MDNS function; the following three parameters need to be set.
‣ 0: disables the MDNS function; the following three parameters need not to be set.
Parameters
• <hostname>: MDNS host name

• <server_name>: MDNS server name

• <server_port>: MDNS server port

• Please do not use special characters (such as .) or a protocol name (for example, http) for
Notes <hostname> and <server_name>.
• ESP8266 SoftAP mode does not support the MDNS function for now.

Example AT+MDNS=1,"espressif","iot",8080

4.2.30. AT+CWHOSTNAME—Configures the Name of ESP8266 Station

Query Command:
Set Command:
Commands AT+CWHOSTNAME?

AT+CWHOSTNAME=<hostname>

Function: Checks the host name of

Function: Sets the host name of ESP8266 Station.
ESP8266 Station.

+CWHOSTNAME:<host name> OK

OK
If the Station mode is not enabled, the command
will return:

If the station mode is not enabled, the

Response
command will return:
ERROR
+CWHOSTNAME:<null>

OK

Parameters <hostname>: the host name of the ESP8266 Station, the maximum length is 32 bytes.

• The configuration changes are not saved in the flash.

Notes • The default host name of the ESP8266 Station is ESP_XXXXXX; XXXXXX is the lower 3 bytes of
the MAC address, for example, +CWHOSTNAME:<ESP_A378DA>.

AT+CWMODE=3

Example
AT+CWHOSTNAME="my_test"

4.2.31. AT+CWCOUNTRY_CUR—Set ESP8266 WiFi Country Code; Configuration Not Saved in the
Flash

Set Command:
Query Command:
AT+CWCOUNTRY_CUR=<country_policy>,<country_co
AT+CWCOUNTRY_CUR?

Commands de>,<start_channel>,<total_channel_count>

Function: Check the current WiFi country

Function: Set the current WiFi country code of
code of ESP8266.
ESP8266.

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+CWCOUNTRY_CUR:<country_policy>,<cou
ntry_code>,<start_channel>,<total_ch
annel_count>
OK

Response OK
Command AT+CWCOUNTRY_CUR? will return
the actual value of WiFi country code,
which may be changed to the same as the
AP it connected to.

<country_policy>:
• 0: will change the county code to be the same as the AP that ESP is connected to
• 1: the country code will not change, always be the one set by command.
Parameters <country_code>: country code, the length can be 3 characters at most; but the third one is a
special character which will not be shown when querying by command AT+CWCOUNTRY_CUR?
<start_channel> : the channel number to start at
<total_channel_count> : channel count

Notes The configuration changes will NOT be saved in the flash.

AT+CWMODE=3

Example
AT+CWCOUNTRY_CUR=1,"CN",1,13

4.2.32. AT+CWCOUNTRY_DEF—Set the default WiFi Country Code of ESP8266; Configuration

Saved in the Flash

Query Command: Set Command:

AT+CWCOUNTRY_DEF?
AT+CWCOUNTRY_DEF=<country_policy>,<country_co
Commands Function: Check the default WiFi country de>,<start_channel>,<total_channel_count>

code of ESP8266 which is saved in the Function: Set the default WiFi country code of
flash. ESP8266, and save in the flash.

+CWCOUNTRY_DEF:<country_policy>,<cou
ntry_code>,<start_channel>,<total_ch
annel_count>
Response OK
OK
Command AT+CWCOUNTRY_DEF? will return
the default WiFi country code which is
stored in the flash.

<country_policy>:
• 0: will change the county code to be the same as the AP that ESP is connected to
• 1: the country code will not change, always be the one set by command.
Parameters <country_code>: country code, the length can be 3 characters at most; but the third one is a
special character which will not be shown when querying by command AT+CWCOUNTRY_DEF?
<start_channel> : the channel number to start at
<total_channel_count> : channel count

Notes The configuration changes will be saved in the flash user parameter area.

AT+CWMODE=3

Example
AT+CWCOUNTRY_DEF=1,"CN",1,13

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5. TCP/IP-Related AT Commands
5.1. Overview
Command Description

AT+CIPSTATUS Gets the connection status

AT+CIPDOMAIN DNS function

AT+CIPSTART Establishes TCP connection, UDP transmission or SSL connection

AT+CIPSSLSIZE Sets the size of SSL buffer

AT+CIPSSLCONF Set configuration of ESP SSL client

AT+CIPSEND Sends data

AT+CIPSENDEX Sends data when length of data is <length>, or when \0 appears in the data

AT+CIPSENDBUF Writes data into TCP-send-buffer

AT+CIPBUFRESET Resets the segment ID count

AT+CIPBUFSTATUS Checks the status of TCP-send-buffer

AT+CIPCHECKSEQ Checks if a specific segment is sent or not

AT+CIPCLOSE Closes TCP/UDP/SSL connection

AT+CIFSR Gets the local IP address

AT+CIPMUX Configures the multiple connections mode

AT+CIPSERVER Deletes/Creates a TCP server

AT+CIPSERVERMAXCONN Set the maximum connections that server allows

AT+CIPMODE Configures the transmission mode

AT+SAVETRANSLINK Saves the transparent transmission link in the flash

AT+CIPSTO Sets timeout when ESP8266 runs as TCP server

AT+PING Ping packets

AT+CIUPDATE Upgrades the software through network

AT+CIPDINFO Shows remote IP and remote port with +IPD

+IPD ESP receives network data

AT+CIPRECVMODE Set TCP Receive Mode

AT+CIPRECVDATA Get TCP Data in Passive Receive Mode

AT+CIPRECVLEN Get TCP Data Length in Passive Receive Mode

AT+CIPSNTPCFG Configures the time domain and SNTP server.

AT+CIPSNTPTIME Queries the SNTP time.

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AT+CIPDNS_CUR Sets user-defined DNS servers; configuration not saved in the flash

AT+CIPDNS_DEF Sets user-defined DNS servers; configuration saved in the flash

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5.2. Commands
5.2.1. AT+CIPSTATUS—Gets the Connection Status

Execute Command AT+CIPSTATUS

STATUS:<stat>

Response
+CIPSTATUS:<link ID>,<type>,<remote IP>,<remote port>,<local port>,<tetype>

• <stat>: status of the ESP8266 Station interface.

‣ 2: The ESP8266 Station is connected to an AP and its IP is obtained.

‣ 3: The ESP8266 Station has created a TCP or UDP transmission.
‣ 4: The TCP or UDP transmission of ESP8266 Station is disconnected.
‣ 5: The ESP8266 Station does NOT connect to an AP.
• <link ID>: ID of the connection (0~4), used for multiple connections.

• <type>: string parameter, "TCP" or "UDP".

Parameters
• <remote IP>: string parameter indicating the remote IP address.

• <remote port>: the remote port number.

• <local port>: ESP8266 local port number.

• <tetype>:

‣ 0: ESP8266 runs as a client.

‣ 1: ESP8266 runs as a server.

5.2.2. AT+CIPDOMAIN—DNS Function

Execute Command AT+CIPDOMAIN=<domain name>

+CIPDOMAIN:<IP address>

OK

Response Or

DNS Fail

ERROR

Parameter <domain name>: the domain name, length should be less than 64 bytes.

AT+CWMODE=1 // set Station mode

Example AT+CWJAP="SSID","password" // access to the internet

AT+CIPDOMAIN="iot.espressif.cn" // DNS function

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5.2.3. AT+CIPSTART—Establishes TCP Connection, UDP Transmission or SSL Connection

Establish TCP Connection

Single TCP connection (AT+CIPMUX=0): Multiple TCP Connections (AT+CIPMUX=1):

Set
Command AT+CIPSTART=<type>,<remote IP>,<remote AT+CIPSTART=<link ID>,<type>,<remote IP>,<remote
port>[,<TCP keep alive>] port>[,<TCP keep alive>]

OK

or
Response ERROR

If the TCP connection is already established, the response is:

ALREADY CONNECTED

• <link ID>: ID of network connection (0~4), used for multiple connections.

• <type>: string parameter indicating the connection type: "TCP", "UDP" or "SSL".

• <remote IP>: string parameter indicating the remote IP address.

Parameters • <remote port>: the remote port number.

• [<TCP keep alive>]: detection time interval when TCP is kept alive; this function is disabled by
default.
‣ 0: disable TCP keep-alive.
‣ 1 ~ 7200: detection time interval; unit: second (s).

AT+CIPSTART="TCP","iot.espressif.cn",8000

Examples AT+CIPSTART="TCP","192.168.101.110",1000

For more information please see: ESP8266 AT Command Examples.

Establish UDP Transmission

Single connection (AT+CIPMUX=0):

Multiple connections (AT+CIPMUX=1):
Set
AT+CIPSTART=<type>,<remote IP>,<remote
Command AT+CIPSTART=<link ID>,<type>,<remote IP>,<remote
port>[,(<UDP local port>),(<UDP
port>[,(<UDP local port>),(<UDP mode>)]
mode>)]

OK
or
Response ERROR
If the UDP transmission is already established, the response is:

ALREADY CONNECTED

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• <link ID>: ID of network connection (0~4), used for multiple connections.

• <type>: string parameter indicating the connection type: "TCP", "UDP" or "SSL".

• <remote IP>: string parameter indicating the remote IP address.

• <remote port>: remote port number.

• [<UDP local port>]: optional; UDP port of ESP8266.

Parameters • [<UDP mode>]: optional. In the UDP transparent transmission, the value of this parameter has to be 0.

‣ 0: the destination peer entity of UDP will not change; this is the default setting.
‣ 1: the destination peer entity of UDP can change once.
‣ 2: the destination peer entity of UDP is allowed to change.

⚠ Notice:

To use <UDP mode> , <UDP local port> must be set first.

AT+CIPSTART="UDP","192.168.101.110",1000,1002,2

Example
For more information please see: ESP8266 AT Command Examples.

Establish SSL Connection

Set
AT+CIPSTART=[<link ID>,]<type>,<remote IP>,<remote port>[,<TCP keep alive>]
Command

OK

or
Response ERROR

If the TCP connection is already established, the response is:

ALREADY CONNECTED

• <link ID>: ID of network connection (0~4), used for multiple connections.

• <type>: string parameter indicating the connection type: "TCP", "UDP" or "SSL".

• <remote IP>: string parameter indicating the remote IP address.

Parameters • <remote port>: the remote port number.

• [<TCP keep alive>]: detection time interval when TCP is kept alive; this function is disabled by
default.
‣ 0: disable the TCP keep-alive function.
‣ 1 ~ 7200: detection time interval, unit: second (s).

• ESP8266 can only set one SSL connection at most.

• SSL connection does not support UART-Wi-Fi passthrough mode (transparent transmission).
Notes
• SSL connection needs a large amount of memory; otherwise, it may cause system reboot. The
command AT+CIPSSLSIZE=<size> can be used to enlarge the SSL buffer size.

Example AT+CIPSTART="SSL","iot.espressif.cn",8443

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5.2.4. AT+CIPSSLSIZE—Sets the Size of SSL Buffer

Set Command AT+CIPSSLSIZE=<size>

Response OK

Parameters <size>: the size of the SSL buffer; range of value: [2048, 4096].

Example AT+CIPSSLSIZE=4096

5.2.5. AT+CIPSSLCCONF - Sets Configuration of ESP SSL Client

Query Command: Set Command:

Commands AT+CIPSSLCCONF?
AT+CIPSSLCCONF=<SSL mode>

Function: Get configuration of the ESP8266 SSL Function: Set configuration of the ESP8266 SSL
client. client.

+CIPSSLCCONF:<SSL mode>
Response OK
OK

<SSL mode>:

Parameters ‣ bit0：if set to be 1, certificate and private key will be enabled, so SSL server can verify ESP8266; if
0, then will not.
‣ bit1：if set to be 1, CA will be enabled, so ESP8266 can verify SSL server; if 0, then will not.

• If certificates need to be enabled, please call this command before SSL connection is established.

• If certificates need to be enabled, please refer to the ESP8266 SSL User Guide to generate
certificates.
- esp_ca_cert.bin downloads to 0xFB000 by default
Notes - esp_cert_private_key.bin downloads to 0xFC000 by default

- Users can revise the SYSTEM_PARTITION_SSL_CLIENT_CA_ADDR and

SYSTEM_PARTITION_SSL_CLIENT_CERT_PRIVKEY_ADDR in user_main.c to change the
downloading addresses.
• This configuration will be saved in the flash user parameter area.

AT+CWMODE=1 // enable sta mode

AT+CWJAP="SSID","PASSWORD" // connect to an AP

AT+CIPSNTPCFG=1,8 // set SNTP timezone

Example
AT+CIPSNTPTIME? // get SNTP time

AT+CIPSSLCCONF=2

AT+CIPSTART="SSL","192.168.3.38",8443

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5.2.6. AT+CIPSEND—Sends Data

Set Command:
1. Single connection: (+CIPMUX=0)
AT+CIPSEND=<length>
2. Multiple connections: (+CIPMUX=1) Execute Command:
AT+CIPSEND=<link ID>,<length> AT+CIPSEND
Commands
3. Remote IP and ports can be set in UDP Function: to start sending data in transparent
transmission: transmission mode.
AT+CIPSEND=[<link ID>,]<length> [,<remote
IP>,<remote port>]
Function: to configure the data length in normal
transmission mode.

Send data of designated length.

Wrap return > after executing this command.
Wrap return > after the Set Command. Begin
Enter transparent transmission, with a 20-ms
receiving serial data. When data length defined by
interval between each packet, and a maximum of
<length> is met, the transmission of data starts.
2048 bytes per packet.
If the connection cannot be established or gets
When a single packet containing +++ is received,
disrupted during data transmission, the system
ESP8266 returns to normal command mode.
Response returns:
Please wait for at least one second before
ERROR sending the next AT command.
If data is transmitted successfully, the system This command can only be used in transparent
returns: transmission mode which requires single
SEND OK
connection.
If it failed, the system returns: For UDP transparent transmission, the value of
SEND FAIL <UDP mode> has to be 0 when using AT+CIPSTART.

• <link ID>: ID of the connection (0~4), for multiple

connections.
• <length>: data length, MAX: 2048 bytes.
Parameters • [<remote IP>]: remote IP can be set in UDP -
transmission.
• [<remote port>]: remote port can be set in UDP
transmission.

Example For more information please see: ESP8266 AT Command Examples.

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5.2.7. AT+CIPSENDEX—Sends Data

1. Single connection: (+CIPMUX=0)

AT+CIPSENDEX=<length>
2. Multiple connections: (+CIPMUX=1)
Set
AT+CIPSENDEX=<link ID>,<length>
Command
3. Remote IP and ports can be set in UDP transmission:

AT+CIPSENDEX=[<link ID>,]<length>[,<remote IP>,<remote port>]

Function: to configure the data length in normal transmission mode.

Send data of designated length.

Wrap return > after the Set Command. Begin receiving serial data. When the requirement of data length,
determined by <length>, is met, or when \0 appears in the data, the transmission starts.

If connection cannot be established or gets disconnected during transmission, the system returns:
Response ERROR

If data are successfully transmitted, the system returns:

SEND OK

If it failed, the system returns:

SEND FAIL

• <link ID>: ID of the connection (0~4), for multiple connections.

• <length>: data length, MAX: 2048 bytes.

Parameters • When the requirement of data length, determined by <length>, is met, or when \0 appears, the
transmission of data starts. Go back to the normal command mode and wait for the next AT
command.
• When sending \0, please send it as \\0.

5.2.8. AT+CIPSENDBUF—Writes Data into the TCP-Send-Buffer

1. Single connection: (+CIPMUX=0)

Set AT+CIPSENDBUF=<length>
Command 2. Multiple connections: (+CIPMUX=1)
AT+CIPSENDBUF=<link ID>,<length>

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<current segment ID>,<segment ID of which sent successfully>

OK

>
• Wrap return > begins receiving serial data; when the length of data defined by the parameter <length>
is met, the data is sent; if the data length over the value of <length>, the data will be discarded, and
the command returns busy.

• If the connection cannot be established, or if it is not a TCP connection, or if the buffer is full, or some
other error occurs, the command returns
Response ERROR
• If data is transmitted successfully,

‣ for single connection, the response is:

<segment ID>,SEND OK

‣ for multiple connections, the response is:

<link ID>,<segment ID>,SEND OK

• If it failed, the system returns:

SEND FAIL

• <link ID>: ID of the connection (0~4), for multiple connections.

Parameters • <segment ID>: uint32; the ID assigned to each data packet, starting from 1; the ID number increases
by 1 every time a data packet is written into the buffer.
• <length>: data length; MAX: 2048 bytes.

• This command only writes data into the TCP-send-buffer, so it can be called continually, and the user
need not wait for SEND OK; if a TCP segment is sent successfully, it will return <segment ID>,SEND OK.
Notes • Before data length reaches the value defined by <length>, input +++ can switch back from data mode
to command mode, and discard the data received before.
• This command can NOT be used for SSL connections.

5.2.9. AT+CIPBUFRESET—Resets the Segment ID Count

1. Single connection: (+CIPMUX=0)

AT+CIPBUFRESET
Set Command
2. Multiple connections: (+CIPMUX=1)
AT+CIPBUFRESET=<link ID>

OK
Response If the connection is not established or there is still TCP data waiting to be sent, the response will be:

ERROR

Parameter <link ID>: ID of the connection (0~4), for multiple connections.

Note This command can only be used when AT+CIPSENDBUF is used.

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5.2.10. AT+CIPBUFSTATUS—Checks the Status of the TCP-Send-Buffer

1. Single connection: (+CIPMUX=0)

AT+CIPBUFSTATUS
Set Command
2. Multiple connections: (+CIPMUX=1)

AT+CIPBUFSTATUS=<link ID>

<next segment ID>,<segment ID sent >,<segment ID successfully sent>,<remain buffer

Response size>,<queue number>
OK

• <next segment ID>: the next segment ID obtained by AT+CIPSENDBUF;

• <segment ID sent>: the ID of the TCP segment last sent;

• Only when <next segment ID> - <segment ID sent> = 1, can AT+CIPBUFRESET be called to reset the
counting.

Parameters
• <segment ID successfully sent>: the ID of the last successfully sent TCP segment;

• <remain buffer size>: the remaining size of the TCP-send-buffer;

• <queue number>: available TCP queue number; it’s not reliable and should be used as a reference
only.

Notes This command can not be used for SSL connection.

For example, in single connection, the command AT+CIPBUFSTATUS returns:

20,15,10,200,7

Description:
• 20: means that the latest segment ID is 19; so when calling AT+CIPSENDBUF the next time, the
segment ID returned is 20;
Example • 15: means that the TCP segment with the ID 15 is the last segment sent, but the segment may
not be successfully sent;
• 10: means that the TCP segment with the ID 10 was sent successfully;

• 200: means that the remaining size of the TCP-send-buffer is 200 bytes;

• 7: the available TCP queue number; it is not reliable and should be used as a reference only;
when the queue number is 0, no TCP data can be sent.

5.2.11. AT+CIPCHECKSEQ—Checks If a Specific Segment Was Successfully Sent

1. Single connection: (+CIPMUX=0)

AT+CIPCHECKSEQ=<segment ID>
Set Command
2. multiple connections: (+CIPMUX=1)
AT+CIPCHECKSEQ=<link ID>,<segment ID>

[<link ID>,]<segment ID>,<status>

Response
OK

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• The command can only be used to record the status of the last 32 segments at most.

• [<link ID>]: ID of the connection (0~4), for multiple connection;

• <segment ID>: the segment ID obtained by calling AT+CIPSENDBUF;

Parameters
• <status>:
‣ FALSE: the segment-sending failed;
‣ TRUE: the segment was sent successfully.

Notes This command can only be used when AT+CIPSENDBUF is used.

5.2.12. AT+CIPCLOSEMODE—Set the Close Mode of TCP Connection

1. Single connection: (+CIPMUX=0)

AT+CIPCLOSEMODE=<enable_abort>
Commands
2. multiple connections: (+CIPMUX=1)
AT+CIPCLOSEMODE=<link ID>,<enable_abort>

Response OK

<link ID>: ID of the connection

Parameters
<enable_abort>: 0, normal disconnect; 1, abort to disconnect

• Default is the normal disconnect mode. Usually the abort mode should not be enabled.

• If the abort mode is needed, please use this command after TCP connection is established. And
Notes the configuration only takes effect in the current connection. If the connection breaks, you need to
set it again after new connection is established.

• This configuration only works on normal TCP connection, cannot be used on SSL connection.

AT+CIPSTART=0,"TCP","192.168.3.60",3400
Example AT+CIPCLOSEMODE=0,1

AT+CIPCLOSE=0

5.2.13. AT+CIPCLOSE—Closes the TCP/UDP/SSL Connection

Set Command (used in multiple connections): Execute Command (used in multiple

Commands AT+CIPCLOSE=<link ID>
connections):
Function: close the TCP/UDP Connection. AT+CIPCLOSE

Response OK

<link ID>: ID of the connection to be closed. When ID

Parameters is 5, all connections will be closed. (In server mode, the -
ID 5 has no effect.)

5.2.14. AT+CIFSR—Gets the Local IP Address

Execute
AT+CIFSR
Command

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+CIFSR:APIP,<SoftAP IP address>

+CIFSR:APMAC,<SoftAP MAC address>

Response +CIFSR:STAIP,<Station IP address>

+CIFSR:STAMAC,<Station MAC address>

OK

<IP address>:

IP address of the ESP8266 SoftAP;

IP address of the ESP8266 Station.

Parameters
<MAC address>:

MAC address of the ESP8266 SoftAP;

MAC address of the ESP8266 Station.

Notes Only when the ESP8266 Station is connected to an AP can the Station IP can be queried.

5.2.15. AT+CIPMUX—Enable or Disable Multiple Connections

Set Command:
Query Command:
Commands AT+CIPMUX=<mode>
AT+CIPMUX?
Function: to set the connection type.

+CIPMUX:<mode>

Response OK
OK

<mode>:
Parameters
‣ 0: single connection
‣ 1: multiple connections

• The default mode is single connection mode.

• Multiple connections can only be set when transparent transmission is disabled (AT+CIPMODE=0).
Notes • This mode can only be changed after all connections are disconnected.

• If the TCP server is running, it must be deleted (AT+CIPSERVER=0) before the single connection
mode is activated.

Example AT+CIPMUX=1

5.2.16. AT+CIPSERVER—Deletes/Creates TCP Server

Set Command AT+CIPSERVER=<mode>[,<port>]

Response OK

• <mode>:

Parameters ‣ 0: deletes server.

‣ 1: creates server.
• <port>: port number; 333 by default.

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• A TCP server can only be created when multiple connections are activated (AT+CIPMUX=1).
Notes • A server monitor will automatically be created when the TCP server is created.

• When a client is connected to the server, it will take up one connection and be assigned an ID.

AT+CIPMUX=1

Example
AT+CIPSERVER=1,1001

5.2.17. AT+CIPSERVERMAXCONN—Set the Maximum Connections Allowed by Server

Query Command: Set Command:

AT+CIPSERVERMAXCONN?
AT+CIPSERVERMAXCONN=<num>
Commands
Function: obtain the maximum number of clients Function: set the maximum number of clients
allowed to connect to the TCP or SSL server. allowed to connect to the TCP or SSL server.

+CIPSERVERMAXCONN:<num>

Response OK
OK

Parameters <num>: the maximum number of clients allowed to connect to the TCP or SSL server, range: [1, 5]
To set this configuration, you should call the command AT+CIPSERVERMAXCONN=<num> before creating
Notes
a server.

AT+CIPMUX=1

Example AT+CIPSERVERMAXCONN=2

AT+CIPSERVER=1,80

5.2.18. AT+CIPMODE—Sets Transmission Mode

Query Command:
Set Command:
AT+CIPMODE?

Commands AT+CIPMODE=<mode>
Function: to obtain information about
Function: to set the transmission mode.
transmission mode.

+CIPMODE:<mode>

Response OK
OK

<mode>:

Parameters ‣ 0: normal transmission mode.

‣ 1: UART-Wi-Fi passthrough mode (transparent transmission), which can only be enabled in TCP
single connection mode or in UDP mode when the remote IP and port do not change.

• The configuration changes will NOT be saved in flash.

Notes • During the UART-Wi-Fi passthrough transmission, if the TCP connection breaks, ESP8266 will
keep trying to reconnect until +++ is input to exit the transmission. If it is a normal TCP transmission
and the TCP connection breaks, ESP8266 will give a prompt and will not attempt to reconnect.

Example AT+CIPMODE=1

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5.2.19. AT+SAVETRANSLINK—Saves the Transparent Transmission Link in Flash

Save TCP Single Connection in Flash

Set Command AT+SAVETRANSLINK=<mode>,<remote IP or domain name>,<remote port>[,<type>,<TCP keep

alive>]

Response OK

• <mode>:

‣ 0: ESP8266 will NOT enter UART-Wi-Fi passthrough mode on power-up.

‣ 1: ESP8266 will enter UART-Wi-Fi passthrough mode on power-up.
• <remote IP>: remote IP or domain name.

Parameters • <remote port>: remote port.

• [<type>] (optional): TCP or UDP, TCP by default.

• [<TCP keep alive>] (optional): TCP is kept alive. This function is disabled by default.

‣ 0: disables the TCP keep-alive function.

‣ 1 ~ 7200: keep-alive detection time interval; unit: second (s).

• This command will save the UART-Wi-Fi passthrough mode and its link in the flash. ESP8266 will
enter the UART-Wi-Fi passthrough mode on any subsequent power cycles.
Notes
• As long as the remote IP (or domain name) and port are valid, the configuration will be saved in the
flash.

Example AT+SAVETRANSLINK=1,"192.168.6.110",1002,"TCP"

Save UDP Transmission in Flash

Set Command AT+SAVETRANSLINK=<mode>,<remote IP>,<remote port>,<type>[,<UDP local port>]

Response OK

• <mode>:

‣ 0: normal mode; ESP8266 will NOT enter UART-Wi-Fi passthrough mode on power-up.
‣ 1: ESP8266 enters UART-Wi-Fi passthrough mode on power-up.
• <remote IP>: remote IP or domain name.
Parameters
• <remote port>: remote port.

• [<type>] (optional): UDP; TCP by default.

• [<UDP local port>] (optional): local port when UDP transparent transmission is enabled on
power-up.

• This command will save the UART-Wi-Fi passthrough mode and its link in the flash. ESP8266 will
enter the UART-Wi-Fi passthrough mode on any subsequent power cycles.
Notes
• As long as the remote IP (or domain name) and port are valid, the configuration will be saved in
the user parameter area in the flash.

Example AT+SAVETRANSLINK=1,"192.168.6.110",1002,"UDP",1005

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5.2.20. AT+CIPSTO—Sets the TCP Server Timeout

Query Command: Set Command:

Commands AT+CIPSTO?
AT+CIPSTO=<time>
Function: to check the TCP server timeout. Function: to set the TCP server timeout.

+CIPSTO:<time>

Response OK
OK

Parameter <time>: TCP server timeout within the range of 0 ~ 7200s.

• ESP8266 configured as a TCP server will disconnect from the TCP client that does not
Notes communicate with it until timeout.
• If AT+CIPSTO=0, the connection will never time out. This configuration is not recommended.

AT+CIPMUX=1

Example AT+CIPSERVER=1,1001

AT+CIPSTO=10

5.2.21. AT+PING—Ping Packets

AT+PING=<IP>

Set Command
Function: Ping packets.

+<time>
OK
Response or

+timeout
ERROR

• <IP>: string; host IP or domain name

Parameters
• <time>: the response time of ping

AT+PING="192.168.1.1"

Notes
AT+PING="www.baidu.com"

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5.2.22. AT+CIUPDATE—Updates the Software Through Wi-Fi

Execute AT+CIUPDATE

Command Function: updates software.

+CIPUPDATE:<n>

Response
OK

• <n>:

‣ 1: find the server.

Parameters ‣ 2: connect to server.
‣ 3: get the software version.
‣ 4: start updating.

• The speed of the upgrade is susceptible to the connectivity of the network.

Notes • ERROR will be returned if the upgrade fails due to unfavourable network conditions. Please wait
for some time before retrying.

• If using Espressif’s AT BIN (/ESP8266_NONOS_SDK/bin/at), AT+CIUPDATE will download a new

AT BIN from the Espressif Cloud.
• If using a user-compiled AT BIN, users need to make their own AT+CIUPDATE upgrade. Espressif
Notes
provides a demo as a reference for local upgrade (/ESP8266_NONOS_SDK/example/at).
• It is suggested that users call AT+RESTORE to restore the factory default settings after upgrading
the AT firmware.

5.2.23. AT+CIPDINFO—Shows the Remote IP and Port with +IPD

Set Command AT+CIPDINFO=<mode>

Response OK

<mode>:
Parameters ‣ 0: does not show the remote IP and port with +IPD.
‣ 1: shows the remote IP and port with +IPD.

Example AT+CIPDINFO=1

5.2.24. +IPD—Receives Network Data

Single connection: multiple connections:

Command
(+CIPMUX=0)+IPD,<len>[,<remote (+CIPMUX=1)+IPD,<link ID>,<len>[,<remote
IP>,<remote port>]:<data> IP>,<remote port>]:<data>

The command is valid in normal command mode. When the module receives network data, it will
send the data through the serial port using the +IPD command.
• [<remote IP>]: remote IP, enabled by command AT+CIPDINFO=1.
Parameters • [<remote port>]: remote port, enabled by command AT+CIPDINFO=1.
• <link ID>: ID number of connection.
• <len>: data length.
• <data>: data received.

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5.2.25. AT+CIPRECVMODE—Set TCP Receive Mode

Set Command: Query Command:

Commands
AT+CIPRECVMODE=<mode> AT+CIPRECVMODE?

+CIPRECVMODE:<mode>

Response OK
OK

<mode>: the receive mode of TCP data is active mode by default.

• 0: active mode - ESP8266 will send all the received TCP data instantly to host MCU through
Parameters UART with header “+IPD".
• 1: passive mode - ESP8266 will keep the received TCP data in an internal buffer (default is 2920
bytes), and wait for host MCU to read the data. If the buffer is full, the TCP transmission will be
blocked.

Example AT+CIPRECVMODE=1

• The configuration is for normal TCP transmission only, and cannot be used on SSL, UDP or WiFi-
UART passthrough mode.
• If the passive mode is enabled, when ESP8266 receives TCP data, it will prompt the following
message in different scenarios:
Note
- for multiple connection mode (AT+CIPMUX=1), the message is: +IPD,<link ID>,<len>

- for single connection mode (AT+CIPMUX=0), the message is: +IPD,<len>

- <len> is the total length of TCP data in buffer

5.2.26. AT+CIPRECVDATA—Get TCP Data in Passive Receive Mode

• For single connection mode (AT+CIPMUX=0)：

AT+CIPRECVDATA=<len>

Set Commands
• For multiple connection mode (AT+CIPMUX=1)：

AT+CIPRECVDATA=<link_id>,<len>

+CIPRECVDATA:<actual_len>,<data>
Response
OK

<link_id>: connection ID in multiple connection mode.

<len>: data length that you want to get, max is 2048 bytes per time.
Parameters
<actual_len>: length of the data you actually get

<data>: the data you get

• In a case of disconnection, the buffered TCP data will still be there and can be read by MCU until
Notes a new connection is established. If the newly established connection happens to use the same
link ID, the previously buffered data in the last connection will be lost.

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AT+CIPRECVMODE=1

// For example, if host MCU gets a message of receiving 100 bytes data in connection with No.0, the
Example message will be as following: +IPD,0,100

// then you can read those 100 bytes by using the command below
AT+CIPRECVDATA=0,100

5.2.27. AT+CIPRECVLEN—Get TCP Data Length in Passive Receive Mode

Query Commands AT+CIPRECVLEN?

+CIPRECVLEN:<data length of link0>,<data length of link1>,<data length of link2>,<data

Response length of link3>,<data length of link4>
OK

Parameters <data length of link>: length of the entire data buffered for the link

AT+CIPRECVLEN?

Example +CIPRECVLEN:100,,,,,
OK

5.2.28. AT+CIPSNTPCFG—Sets the Configuration of SNTP

Set Command:
Query Command:
Commands
AT+CIPSNTPCFG=<enable>[,<timezone>][,<SNTP
AT+CIPSNTPCFG?
server0>,<SNTP server1>,<SNTP server2>]

+CIPSNTPCFG:<enable>,<timezone>
,<SNTP server1>[,<SNTP
Response server2>,<SNTP server3>]
OK

OK

• <enable>:

‣ 0: SNTP is disabled;

‣ 1: SNTP is enabled.

Parameters • <timezone>: time zone; range: [-11,13]; if SNTP is enabled, the <timezone> has to be set;
• <SNTP server0>: optional parameter indicating the first SNTP server;
• <SNTP server1>: optional parameter indicating the second SNTP server;
• <SNTP server2>: optional parameter indicating the third SNTP server.

Example AT+CIPSNTPCFG=1,8,"cn.ntp.org.cn","ntp.sjtu.edu.cn","us.pool.ntp.org"

If the <SNTP server> parameters are not set, servers "cn.ntp.org.cn","ntp.sjtu.edu.cn", and
Note
"us.pool.ntp.org" will be used by default.

5.2.29. AT+CIPSNTPTIME—Checks the SNTP Time

Query Command AT+CIPSNTPTIME?

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+CIPSNTPTIME:<time>

Response
OK

<time>: SNTP time

For example,
Parameters
+CIPSNTPTIME:Thu Aug 04 14:48:05 2016

OK

AT+CWMODE=1 //set as station mode

AT+CWJAP="DemoAP","password" //connect to router, access the internet

Example
AT+CIPSNTPCFG=1,8 //set time zone

AT+CIPSNTPTIME? //get time

5.2.30. AT+CIPDNS_CUR—Sets User-defined DNS Servers; Configuration Not Saved in the Flash

Query Command:
Set Command:
AT+CIPDNS_CUR?

Commands AT+CIPDNS_CUR=<enable>[,<DNS server0>,<DNS server1>]

Function: Get the current DNS

Function: Set user-defined DNS servers.
server.

[+CIPDNS_CUR:<DNS server0>]

Response [+CIPDNS_CUR:<DNS server1>]

OK

OK

• <enable>:

‣ 0: disable to use user-defined DNS servers;

Parameters ‣ 1: enable to use user-defined DNS servers.

• <DNS server0>: optional parameter indicating the first DNS server;
• <DNS server1>: optional parameter indicating the second DNS serve.

Example AT+CIPDNS_CUR=1,"208.67.220.220"

• For command: AT+CIPDNS_CUR=0 (disable to use user-defined DNS servers), "208.67.222.222" will
be used as DNS server by default. And the DNS server may change according to the configuration
of the router which the chip connected to.
Note
• For command: AT+CIPDNS_CUR=1 (enable to use user-defined DNS servers, but the <DNS server>
parameters are not set), servers "208.67.222.222" will be used as DNS server by default.

• <DNS server0> and <DNS server1> cannot be set to the same server.

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 5. TCP/IP-Related AT Commands
!

5.2.31. AT+CIPDNS_DEF—Sets User-defined DNS Servers; Configuration Saved in the Flash

Query Command:
Set Command:
Commands AT+CIPDNS_DEF?

AT+CIPDNS_DEF=<enable>[,<DNS server0>,<DNS server1>]

Function: Get the user-defined DNS

Function: Set user-defined DNS servers.
servers which saved in flash.

[+CIPDNS_DEF:<DNS server0>]

Response [+CIPDNS_DEF:<DNS server1>]

OK

OK

• <enable>:

‣ 0: disable to use a user-defined DNS server;

Parameters ‣ 1: enable to use a user-defined DNS server.

• <DNS server0>: optional parameter indicating the first DNS server;
• <DNS server1>: optional parameter indicating the second DNS serve.

Example AT+CIPDNS_DEF=1,"208.67.220.220"

• This configuration will be saved in the user parameter area of flash.

• For command: AT+CIPDNS_DEF=0 (disable to use user-defined DNS servers), "208.67.222.222" will
be used as DNS server by default. And the DNS server may change according to the configuration
Note of the router which the chip connected to.

• For command: AT+CIPDNS_DEF=1 (enable to use user-defined DNS servers, but the <DNS server>
parameters are not set), servers "208.67.222.222" will be used as DNS server by default.

• <DNS server0> and <DNS server1> cannot be set to the same server.

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 Appendix A
!

A. Appendix A
ESP8266 AT commands below will save the configuration changes in flash:

AT Command Examples

Configuration Saved in the User Parameter Area in the Flash

AT+UART_DEF AT+UART_DEF=115200,8,1,0,3

AT+CWDHCP_DEF AT+CWDHCP_DEF=1,1

AT+CIPSTAMAC_DEF AT+CIPSTAMAC_DEF="18:fe:35:98:d3:7b"

AT+CIPAPMAC_DEF AT+CIPAPMAC_DEF="1a:fe:36:97:d5:7b"

AT+CIPSTA_DEF AT+CIPSTA_DEF="192.168.6.100"

AT+CIPAP_DEF AT+CIPAP_DEF="192.168.5.1"

AT+CWDHCPS_DEF AT+CWDHCPS_DEF=1,3,"192.168.4.10","192.168.4.15"

AT+SAVETRANSLINK AT+SAVETRANSLINK_DEF=1,"192.168.6.10",1001

AT+CIPDNS_DEF AT+CIPDNS_DEF=1,"208.67.220.220"

AT+SYSMSG_DEF AT+SYSMSG_DEF=3

AT+CWCOUNTRY_DEF AT+CWCOUNTRY_DEF=1,"CN",1,13

AT+CIPSSLCCONF AT+CIPSSLCCONF=2

Configuration Saved in the System Parameter Area in the Flash

AT+CWMODE_DEF AT+CWMODE_DEF=3

AT+CWJAP_DEF AT+CWJAP_DEF="abc","0123456789"

AT+CWSAP_DEF AT+CWSAP_DEF="ESP8266","12345678",5,3

AT+CWAUTOCONN AT+CWAUTOCONN=1

⚠ Notice:

• Only when the configuration changes will the AT firmware write the new configuration into the flash. Therefore,
users need not be concerned about wearing out the flash on repeated application of commands that set the same
default configurations over and over again.
• For 512 KB + 512 KB Flash Map, the user parameter area is 0x7C000 ~ 0x80000, 16 KB;

• For 1024 KB + 1024 KB Flash Map: the user parameter area is 0xFC000 ~ 0x100000, 16 KB;

• The system parameter area is always the last 16 KB in the flash.

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 Appendix B
!

B. Appendix B
Messages of ESP8266 AT are as below:

Messages Description

ready The AT firmware is ready.

ERROR AT command error, or error occurred during execution.

WIFI CONNECTED ESP8266 station connected to an AP.

WIFI GOT IP ESP8266 station got IP address.

WIFI DISCONNECT ESP8266 station disconnected from an AP.

busy s... Busy sending. The system is sending data now, cannot accept the newly input.

Busy processing. The system is in process of handling the previous command,

busy p...
cannot accept the newly input.

<conn_id>,CONNECT A network connection of which ID is <conn_id> is established.

<conn_id>,CLOSED A network connection of which ID is <conn_id> ends.

+IPD Received network data.

+STA_CONNECTED:<sta_mac> A station connects to the ESP8266 softAP.

+DIST_STA_IP:<sta_mac>,<sta_ip> ESP8266 softAP distributes an IP address to the station connected.

+STA_DISCONNECTED:<sta_mac> A station disconnects from the ESP8266 softAP.

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 Appendix C
!

C. Q&A
If you have any questions about the execution of AT commands, please contact us via Espressif
Technical Inquiries. Please describe the issues that you might encounter, including any relevant details,
as follows:
• AT Version information or AT Command: You can use command AT+GMR to acquire information
on your current AT command version.
• Hardware Module information: for example, ESP-WROOM-02.

• Details of the test steps, for example:

AT+CWMODE_CUR=1

OK

AT+GMR

AT version:0.23.0.0(Apr 24 2015 21:11:01)

SDK version:1.0.1

compile time:Apr 24 2015 21:19:31

OK

AT+CIPSTAMAC_DEF="14:CF:11:22:33:05"

OK

• If possible, please provide the printed log information, such as:

ets Jan 8 2013,rst cause: 1, boot mode: (3,3)

load 0x40100000, len 26336, room 16

tail 0

chksum 0xde

load 0x3ffe8000, len 5672, room 8

tail 0

chksum 0x69

load 0x3ffe9630, len 8348, room 8

tail 4

chksum 0xcb

csum 0xcb

SDK version: 0.9.1

addr not ack when tx write cmd

mode : sta(18: fe: 34: 97: d5: 7b) + softAP(1a: fe: 34: 97: d5: 7b)

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