program for Dual DAC, square wave in 8051

#include <REG51xD2.H>

#include "lcd.h"

sbit Amp = P3^3; /* Port line to change amplitude */

sbit Fre = P3^2; /* Port line to change frequency */

void delay(unsigned int x) /* delay routine */

{

for(;x>0;x--);

}

main()

{

unsigned char on = 0x7f,off=0x00;

unsigned int fre = 100;

InitLcd(); /* Initialize LCD */

WriteString("Squarewave"); /* Write to LCD */

while(1)

{

if(!Amp) /* if user choice is to change amplitude */

{

while(!Amp); /* wait for key release */

on+=0x08; /* Increase the amplitude */

}

if(!Fre) /* if user choice is to change frequency */

{

if(fre > 1000) /* if frequency exceeds 1000 reset to default */

fre = 100;

while(!Fre); /* wait for key release */

fre += 50; /* Increase the frequency */

}

P0=on; /* write amplitude to port */

P1=on;

delay(fre);

P0 = off; /* clear port */

P1 = off;

delay(fre);

}

}