Programming 8051 Microcontroller

Assembly Programming for ADC0804

	rd equ P1.0           ;Read signal P1.0
wr equ P1.1 ;Write signal P1.1
cs equ P1.2 ;Chip Select P1.2
intr equ P1.3 ;INTR signal P1.3

adc_port equ P2 ;ADC data pins P2
adc_val equ 30H ;ADC read value stored here

org 0H
start: ;Start of Program
acall conv ;Start ADC conversion
acall read ;Read converted value
mov P3,adc_val ;Move the value to Port 3
sjmp start ;Do it again

conv: ;Start of Conversion
clr cs ;Make CS low
clr wr ;Make WR Low
setb wr ;Make WR High
setb cs ;Make CS high
jb intr,wait ;Wait for INTR signal
ret ;Conversion done

read: ;Read ADC value
clr cs ;Make CS Low
clr rd ;Make RD Low
mov a,adc_port ;Read the converted value
mov adc_val,a ;Store it in local variable
setb rd ;Make RD High
setb cs ;Make CS High
ret ;Reading done

Programming 8051 in C for ADC0804

#include <REGX51.H>     
#define adc_port P2 //ADC Port
#define rd P1_0 //Read signal P1.0
#define wr P1_1 //Write signal P1.1
#define cs P1_2 //Chip Select P1.2
#define intr P1_3 //INTR signal P1.3

void conv(); //Start of conversion function
void read(); //Read ADC function

unsigned char adc_val;

void main() {
while (1) { //Forever loop
conv(); //Start conversion
read(); //Read ADC
P3 = adc_val; //Send the read value to P3

void conv() {
cs = 0; //Make CS low
wr = 0; //Make WR low
wr = 1; //Make WR high
cs = 1; //Make CS high
while (intr); //Wait for INTR to go low

void read() {
cs = 0; //Make CS low
rd = 0; //Make RD low
adc_val = adc_port; //Read ADC port
rd = 1; //Make RD high
cs = 1; //Make CS high

This finishes our ADC tutorial along with interfacing of ADC0804. If you have any questions or doubts please post on forum.


Thu Oct 30 2014, 06:02 PM
This is a chat box..create a thread if you need help...but we don't do homework
Tue Oct 28 2014, 07:33 PM
hi rickey...anyone got the pgm...pls gimme now
Tue Oct 28 2014, 06:35 PM
hi vinni even i need that program. help me if you get it
Tue Oct 28 2014, 03:22 PM
1. Using a look-up table in Flash ROM and accumulator offset indexed addressing mode, write a program that acts as a timer. The timer should count from 0 to 59 seconds. After reaching 59, it should go back to 0 on the next second and continue to count up. The timer should use the seven-segment display. The look-up table should contain information on how to display the digits 0 – 9 on the seven-segment display
Tue Oct 28 2014, 03:22 PM
hello Rickey..i need this pgm very urgently
Tue Oct 28 2014, 01:42 AM
Boy Donald
Dear sir, thanks before. i have some project urgent for my school and my project need this digital countdown timer using 7 segmen display. but your project only show ten minutes countdown, i need your help, can you show me more to change the minute or set the time manually. thank you, sorry for disturbing you.
Tue Oct 28 2014, 01:32 AM
Boy Donald
dear sir
Tue Oct 28 2014, 01:19 AM
Boy Donald
Rickey you inspired me a lot but why i can not change the time ( minute
Sun Oct 26 2014, 02:51 AM
sandeep bankar
dear sir I m facing problem to read number of incoming call in gsm 900 a. pls help how to read it in atmel avr microcontroller.
Mon Oct 20 2014, 11:22 AM
@skrishna, please post in forum so we can help you better.



Thu Oct 30 2014, 06:34 AM
Mon Oct 27 2014, 01:23 PM
Sun Oct 26 2014, 01:06 AM
Thu Oct 23 2014, 04:18 PM
Sun Oct 19 2014, 01:56 PM
Thu Oct 16 2014, 08:48 AM
Tue Oct 14 2014, 06:23 PM
Mon Oct 13 2014, 05:48 AM


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