DEPT.
OF ECE EMBEDDED-C LAB
EMBEDDED C LABORATORY
1. Program to toggle all the bits of Port P1 continuously with 250 mS
delay.
2. Program to toggle only the bit P1.5 continuously with some delay. Use
Timer 0, mode 1 to create delay.
3. Program to interface a switch and a buzzer to two different pins of a
Port such that the buzzer should sound as long as the switch is
pressed.
4. Program to interface LCD data pins to port P1 and display a message
on it.
5. Program to interface keypad. Whenever a key is pressed, it should be
displayed on LCD.
6. Program to interface seven segment display unit.
7. Program to transmit a message from Microcontroller to PC serially
using RS232.
8. Program to receive a message from PC serially using RS232.
9. Program to get analog input from Temperature sensor and display the
temperature value on PC Monitor.
10. Program to interface Stepper Motor to rotate the motor in
clockwise and anticlockwise directions
11. Program to Sort RTOS on to 89C51 development board.
12. Program to interface Elevator.
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
1. Write an 8051 C program to send values 00 FF to port P1.
Solution:
#include <reg51.h>
void main(void)
Unsigned char z;
for (z=0; z<=255;z++)
P1=z;
2. Write an 8051 C program to send hex values for ASCII
characters of 0, 1, 2, 3, 4, 5, A, B, C, and D to port P1.
Solution:
#include <reg51.h>
void main(void)
unsigned char bvrit[]=012345ABCD;
unsigned char z;
for (z=0;z<=10;z++)
P1=bvrit[z];
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
3. Write an 8051 C program to toggle all the bits of P1
continuously.
Solution:
#include <reg51.h>
void main(void)
for (;;)
p1=0x55;
p1=0xAA;
4. Write an 8051 C program to send values of 4 to +4 to port P1.
( Signed numbers)
Solution:
#include <reg51.h>
void main(void)
char bvrit[]={+1,-1,+2,-2,+3,-3,+4,-4};
unsigned char z;
for (z=0;z<=8;z++)
P1=bvrit[z];
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
5. Write an 8051 C program to toggle bit D0 of the port P1 (P1.0)
50,000 times.
Sol:
#include <reg51.h>
sbit MYBIT=P1^0;
void main(void)
unsigned int z;
for (z=0;z<=50000;z++)
MYBIT=0;
MYBIT=1;
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
6. Write an 8051 C program to toggle bits of P1 continuously forever
with some delay.
Sol:
//Toggle P1 forever with some delay in between on and off
#include <reg51.h>
void main(void)
unsigned int x;
for (;;) //repeat forever
p1=0x55;
for (x=0;x<40000;x++); //delay size unknown
p1=0xAA;
for (x=0;x<40000;x++);
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
7. Write an 8051 C program to toggle bits of P1 ports continuously with
a 250 ms.
Sol:
#include <reg51.h>
void MSDelay(unsigned int);
void main(void)
while (1) //repeat forever
p1=0x55;
MSDelay(250);
p1=0xAA;
MSDelay(250);
void MSDelay(unsigned int itime)
unsigned int i,j;
for (i=0;i<itime;i++)
for (j=0;j<1275;j++);
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
8. LEDs are connected to bits P1 and P2. Write an 8051 C program that
shows the count from 0 to FFH (0000 0000 to 1111 1111 in binary)
on the LEDs.
Sol:
#include <reg51.h>
#define LED P2;
void main(void)
P1=00; //clear P1
LED=0; //clear P2
for (;;) //repeat forever
P1++; //increment P1
LED++; //increment P2
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
9. Write an 8051 C program to get a byte of data form P1, wait
1/2 second, and then send it to P2.
Solution:
#include <reg51.h>
void MSDelay(unsigned int);
void main(void)
unsigned char mybyte;
P1=0xFF; //make P1 input port
while (1)
mybyte=P1; //get a byte from P1
MSDelay(500);
P2=mybyte; //send it to P2
10. Write an 8051 C program to get a byte of data form P0. If
it is less than 100, send it to P1; otherwise, send it to P2.
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
Sol:
#include <reg51.h>
void main(void)
unsigned char mybyte;
P0=0xFF; //make P0 input port
while (1)
mybyte=P0; //get a byte from P0
if (mybyte<100)
P1=mybyte; //send it to P1
else
P2=mybyte; //send it to P2
11. Write an 8051 C program to toggle only bit P2.4
continuously without disturbing the rest of the bits of P2.
Solution:
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
//Toggling an individual bit
#include <reg51.h>
sbit mybit=P2^4;
void main(void)
while (1)
mybit=1; //turn on P2.4
mybit=0; //turn off P2.4
12. Write an 8051 C program to monitor bit P1.5. If it is high,
send 55H to P0; otherwise, send AAH to P2.
Sol: #include <reg51.h>
sbit mybit=P1^5;
void main(void)
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
mybit=1; //make mybit an input
while (1)
if (mybit==1)
P0=0x55;
else
P2=0xAA;
13. A door sensor is connected to the P1.1 pin, and a buzzer
is connected to P1.7. Write an 8051 C program to monitor the
door sensor, and when it opens, sound the buzzer. You can
sound the buzzer by sending a square wave of a few hundred
Hz.
Sol: #include <reg51.h>
void MSDelay(unsigned int);
sbit Dsensor=P1^1;
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
sbit Buzzer=P1^7;
void main(void)
Dsensor=1; //make P1.1 an input
while (1)
while (Dsensor==1) //while it opens
Buzzer=0;
MSDelay(200);
Buzzer=1;
MSDelay(200);
14. The data pins of an LCD are connected to P1. The
information is latched into the LCD whenever its Enable pin
goes from high to low. Write an 8051 C program to send The
Earth is but One Country to this LCD.
Sol:
#include <reg51.h>
#define LCDData P1 //LCDData declaration
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
sbit En=P2^0; //the enable pin
void main(void)
unsigned char message[]=The Earth is but One Country;
unsigned char z;
for (z=0;z<28;z++) //send 28 characters
LCDData=message[z];
En=1; //a high--to-low pulse to latch
data
En=0;
15. Write an 8051 C program to toggle all the bits of P0, P1,
and P2 continuously with a 250 ms delay. Use the sfr keyword
to declare the port addresses.
Solution:
//Accessing Ports as SFRs using sfr data type
sfr P0=0x80;
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
sfr P1=0x90;
sfr P2=0xA0;
void MSDelay(unsigned int);
void main(void)
while (1)
P0=0x55;
P1=0x55;
P2=0x55;
MSDelay(250);
P0=0xAA;
P1=0xAA;
P2=0xAA;
MSDelay(250);
16. Write an 8051 C program to turn bit P1.5 on and off
50,000 times.
Solution:
sbit MYBIT=0x95;
void main(void)
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
Unsigned int z;
for (z=0;z<50000;z++)
MYBIT=1;
MYBIT=0;
Notice that there is no #includes <reg51.h>.This allows us to access any
byte of the SFR RAM space 80 FFH. This is widely used for the new
generation of 8051 microcontrollers.
17. Write an 8051 C program to get the status of bit P1.0,
save it, and send it to P2.7 continuously.
Sol:
#include <reg51.h>
sbit inbit=P1^0;
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
sbit outbit=P2^7;
bit membit; //use bit to declare bit- addressable memory
void main(void)
while (1)
membit=inbit; //get a bit from P1.0
outbit=membit; //send it to P2.7
18. Run the following program on your simulator and
examine the results.
Sol:
#include <reg51.h>
void main(void)
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
P0=0x35 & 0x0F; //ANDing
P1=0x04 | 0x68; //ORing
P2=0x54 ^ 0x78; //XORing
P0=~0x55; //inversing
P1=0x9A >> 3; //shifting right 3
P2=0x77 >> 4; //shifting right 4
P0=0x6 << 4; //shifting left 4
19. Write an 8051 C program to toggle all the bits of P0 and
P2 continuously with a 250 ms delay. Using the inverting and
Ex-OR operators, respectively.
Sol:
#include <reg51.h>
void MSDelay(unsigned int);
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
void main(void)
P0=0x55;
P2=0x55;
while (1)
P0=~P0;
P2=P2^0xFF;
MSDelay(250);
20. Write an 8051 C program to get bit P1.0 and send it to
P2.7 after inverting it.
Sol:
#include <reg51.h>
sbit inbit=P1^0;
sbit outbit=P2^7;
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
bit membit;
void main(void)
while (1)
membit=inbit; //get a bit from P1.0
outbit=~membit; //invert it and send it to P2.7
21. Write an 8051 C program to read the P1.0 and P1.1 bits
and issue an ASCII character to P0 according to the following
table.
P1.1 P1.0
0 0 Send 0 to P0
0 1 Send 1 to P0
1 0 Send 2 to P0
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
1 1 Send 3 to P0
Solution:
#include <reg51.h>
void main(void)
unsignbed char z;
z=P1;
z=z&0x3;
switch (z)
case(0):
P0=0;
break;
case(1):
P0=1;
break;
case(2):
P0=2;
break;
case(3):
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
P0=3;
break;
22. Write an 8051 C program to convert packed BCD 0x29 to
ASCII and display the bytes on P1 and P2.
Sol:
#include <reg51.h>
void main(void)
unsigned char x,y,z;
unsigned char mybyte=0x29;
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
x=mybyte&0x0F;
P1=x|0x30;
y=mybyte&0xF0;
y=y>>4;
P2=y|0x30;
23. Write an 8051 C program to convert ASCII digits of 4
and 7 to packed BCD and display them on P1.
Sol:
#include <reg51.h>
void main(void)
unsigned char bcdbyte;
unsigned char w=4;
unsigned char z=7;
w=w&0x0F;
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
w=w<<4;
z=z&0x0F;
bcdbyte=w|z;
P1=bcdbyte;
24. Write an 8051 C program to calculate the checksum byte
for the data 25H, 62H, 3FH, and 52H.
Sol:
#include <reg51.h>
void main(void)
unsigned char mydata[]={0x25,0x62,0x3F,0x52};
unsigned char sum=0;
unsigned char x;
unsigned char chksumbyte;
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
for (x=0;x<4;x++)
P2=mydata[x];
sum=sum+mydata[x];
P1=sum;
chksumbyte=~sum+1;
P1=chksumbyte;
25. Write an 8051 C program to perform the checksum
operation to ensure data integrity. If data is good, send ASCII
character G to P0. Otherwise send B to P0.
Sol:
#include <reg51.h>
void main(void)
unsigned char mydata[] ={0x25,0x62,0x3F,0x52,0xE8};
unsigned char shksum=0;
unsigned char x;
for (x=0;x<5;x++)
chksum=chksum+mydata[x];
if (chksum==0)
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
P0=G;
else
P0=B;
26. Write an 8051 C program to convert 11111101 (FD hex) to
decimal and display the digits on P0, P1 and P2.
Sol:
#include <reg51.h>
void main(void)
unsigned char x,binbyte,d1,d2,d3;
binbyte=0xFD;
x=binbyte/10;
d1=binbyte%10;
d2=x%10;
d3=x/10;
P0=d1;
P1=d2;
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
P2=d3;
27. Compile and single-step the following program on your
8051 simulator. Examine the contents of the 128-byte RAM
space to locate the ASCII values.
Sol:
#include <reg51.h>
void main(void)
unsigned char mynum[]=ABCDEF; //RAM space
unsigned char z;
for (z=0;z<=6;z++)
P1=mynum[z];
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
28. Write, compile and single-step the following program on
your 8051 simulator. Examine the contents of the code space
to locate the values.
Sol:
#include <reg51.h>
void main(void)
unsigned char mydata[100]; //RAM space
unsigned char x,z=0;
for (x=0;x<100;x++)
z--;
mydata[x]=z;
P1=z;
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
29. Compile and single-step the following program on your
8051 simulator. Examine the contents of the code space to
locate the ASCII values.
Solution:
#include <reg51.h>
void main(void)
code unsigned char mynum[]=ABCDEF;
unsigned char z;
for (z=0;z<=6;z++)
P1=mynum[z];
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
31. Compare and contrast the following programs and discuss the
advantages and disadvantages of each one.
(a) #include <reg51.h>
void main(void)
P1=H;
P1=E;
P1=L;
P1=L;
P1=O;
(b)
#include <reg51.h>
void main(void)
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
unsigned char mydata[]=HELLO;
unsigned char z;
for (z=0;z<=5;z++)
P1=mydata[z];
(c)
#include <reg51.h>
void main(void)
code unsigned char mydata[]=HELLO;
unsigned char z;
for (z=0; z<=5;z++)
P1=mydata[z];
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
30. Write a C program to send out the value 44H serially one
bit at a time via P1.0. The LSB should go out first.
Sol:
#include <reg51.h>
sbit P1b0=P1^0;
sbit regALSB=ACC^0;
void main(void)
unsigned char conbyte=0x44;
unsigned char x;
ACC=conbyte;
for (x=0;x<8;x++)
P1b0=regALSB;
ACC=ACC>>1;
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
31. Write a C program to send out the value 44H serially one
bit at a time via P1.0. The MSB should go out first.
Solution:
#include <reg51.h>
sbit P1b0=P1^0;
sbit regAMSB=ACC^7;
void main(void)
unsigned char conbyte=0x44;
unsigned char x;
ACC=conbyte;
for (x=0;x<8;x++)
P1b0=regAMSB;
ACC=ACC<<1;
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
32. Write a C program to bring in a byte of data serially one
bit at a time via P1.0. The LSB should come in first.
Solution:
#include <reg51.h>
sbit P1b0=P1^0;
sbit ACCMSB=ACC^7;
bit membit;
void main(void)
unsigned char x;
for (x=0;x<8;x++)
membit=P1b0;
ACC=ACC>>1;
ACCMSB=membit;
P2=ACC;
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
33. Write a C program to bring in a byte of data serially one
bit at a time via P1.0. The MSB should come in first.
Sol:
#include <reg51.h>
sbit P1b0=P1^0;
sbit regALSB=ACC^0;
bit membit;
void main(void)
unsigned char x;
for (x=0;x<8;x++)
membit=P1b0;
ACC=ACC<<1;
regALSB=membit;
P2=ACC;
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
DEPT. OF ECE EMBEDDED-C LAB
M.TECH EMBEDDED SYSTEMS RMCE 2014-15
