SQUARE WAVE GENERATOR EMBEDDED C

                                        SQUARE WAVE GENERATOR                      

  

     One requirement in a wide range of applications is a spontaneous source of some continuous signal, having a regular and definable wave shape. One of the most important of these is a square wave.

     The circuit to the right uses a comparator with both positive and negative feedback to control its output voltage. Because the negative feedback path uses a capacitor while the positive feedback path does not, however, there is a time delay before the comparator is triggered to change state. As a result, the circuit oscillates, or keeps changing state back and forth at a predictable rate.

CIRCUIT SCHEMATIC & OUTPUT:

 LOGIC ANALYSER OUTPUT:

 SOURCE CODE:

#include<regx51.h>

sfr out1=0x90;

sfr out2=0xa0;

sfr out3=0xb0;

unsigned int i;

void main()

{

out1=out2=out3=0x00;

while(1)

  {

    out1=out2=out3=0xaa;

    for(i=0;i<25000;i++);

    out1=out2-out3=0x55;

    for(i=0;i<25000;i++);

  }

}