Experiment No.
PROBLEM DEFINITION: To Illustrate the concept of
DAC(0800) interface by generating different types
of waveforms like Square/Rectangular, Triangular,
Staircase and Sine wave.
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Objectives of the Experiment:
1. To Interface DAC 0800 to 8051 Microcontroller.
2. To develop an 8051 ‘C’ code to generate different waveforms.
3. To use and generate time delays.
2
Department of Computer Science and Engineering, GIT
Theoretical Background of the Experiment
• DAC 0800 is a 8-bit high speed current output
digital to analog converter.
• DAC 0800 is used to convert the digital data
into analog signal.
• Digital data from any port is given to DAC input.
3
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Interfacing Block Diagram
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Algorithm to generate square wave
STEP 1: INCLUDE HEADER FILE “at89c51ed2.h”
STEP 2: FUNCTION DECALARATION OF DELAY ROUTINE.
STEP 3: BEGIN MAIN
STEP 4: SEND THE VALUE 0X00 ON PORT 0
STEP 5: CALL DELAY
STEP 6: SEND THE VALUE 0XFF ON PORT 0
STEP 7: CALL DELAY
STEP 8: REPEAT STEPS 4 TO 7 FOREVER
STEP 9: END MAIN
STEP 10: DELAY ROUTINE: DECLARE VARIABLES
STEP 11: INITIALIZE FOR LOOP TO INCLUDE CERTAIN DELAY
STEP 12: END DELAY ROUTINE.
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Code For Square wave
#include “at89c5ed2.h”
void delay(void);
void main ()
{
while(1)
{
P0 = 0x00; // program outputs 0 and 0xff alternatively to port P0 with a delay
delay(); .
P0 = 0xff;
delay();
}
}
void delay(void) // function to generate delay
{
int i;
for(i=0;i<=300;i++);
}
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Engineering, GIT
Algorithm to generate Staircase wave
STEP 1: INCLUDE HEADER FILE “at89c51ed2.h”
STEP 2: DECLARE VARIABLES
STEP 3: BEGIN MAIN
STEP 4: INITIALIZE FOR LOOP; for (i=0;i<255;i+50) FOR STEP SIZE OF 50
ON Y-AXIS
STEP 5: SEND THE VALUES 0 TO 255 ON PORT 0
STEP 6: INITIALIZE FOR LOOP TO INCLUDE CERTAIN DELAY
STEP 7: SEND i+30 ON PORT 0 TO INCLUDE INCREMENT OF 30 ON X-
AXIS.
STEP 8: END MAIN.
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Code for Staircase wave
#include “at89c51ed2.h”
unsigned int i, j;
void main ()
{
while(1)
{
for(i=0;i<=255;i=i+50)
{
P0=i;
for(j=0;j<100;j++)
{
}
P0=i+30;
}
}
}
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Algorithm to generate Triangular wave
STEP 1: INCLUDE HEADER FILE “at89c51ed2.h”
STEP 2: DECLARE THE VARIABLE COUNT
STEP 3: BEGIN MAIN
STEP 4: INITIALIZE FOR LOOP TO COUNT FROM 0 TO 255;
for (count=0; count! =0xff; count++)
STEP 5: SEND COUNT ON PORT 0
STEP 6: INITIALIZE FOR LOOP TO COUNT FROM 255 TO 0;
for (count=0xff; count! =0; count--)
STEP 7: SEND COUNT ON PORT 0
STEP 8: REPEAT STEPS 4 TO 7 FOREVER.
STEP 9: END MAIN
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Code For Triangular wave
#include “at89c51ed2.h
unsigned char count;
void main ()
{
while(1)
{
for(count=0;count!=0xff;count++)
{ P0=count;
}
for(count=0xff; count>0;count--)
{
P0=count;
}
}
}
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Algorithm to generate Sine wave
STEP 1: INCLUDE HEADER FILE “at89c51ed2.h”
STEP 2: DECLARE THE EXTERNAL RAM ARRAY VALUES. ɵ=7.2 DEGREES. 50
VALUES ARE DECLARED IN AN ARRAY.
STEP 3: DECLARE INDEX VARIABLE
STEP 4: BEGIN MAIN
STEP 5: INITIALIZE FOR LOOP for (count=0; count<49; count++)
STEP 6: SEND ARRAY VALUES ON PORT 0
STEP 7: REPEAT STEPS 5 TO 6 FOREVER
STEP 8: END MAIN
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Code For Sine wave
#include “at89c51xd2.h>
xdata unsigned char sine_tab[49]=
{ 0x80,0x90,0xA1,0xB1,0xC0,0xCD,0xDA,0xE5,0xEE,0xF6,0xFB,0xFE,
0xFF,0xFE,0xFB,0xF6,0xEE,0xE5,0xDA,0xCD,0xC0,0xB1,0xA1,0x90,
0x80,0x70,0x5F,0x4F,0x40,0x33,0x26,0x1B,0x12,0x0A,0x05,0x02,
0x00,0x02,0x05,0x0A,0x12,0x1B,0x26,0x33,0x40,0x4F,0x5F,0x70,0x80};
unsigned int count; // index variable for loop count
void main ()
{
while(1)
{
for(count=0;count<49;count++)
{
P0 = sine_tab[count];
}
}
}
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CONNECTION DETAILS
• PORT 0 TO CN15.
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Learning Outcomes of the Experiment
At the end of the session, students should be able to :
1) Write the 8051 ‘C’ program to generate various waveforms and understand
how to create and use time delays .
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