To write an assembly language program to generate the square waveform of equal duty cycles of 10ms using PIC16F877.

 

Aim:

To write an assembly language program to generate the square waveform of equal

duty cycles of 10ms using PIC16F877.

Algorithm:

Step1. Initialize Port B 3rd pin

Step 2. Initialize the control word with Timer0, 16 bit timer and no prescale

Step 3. Load the timer high and timer low byte with initial count values

Step 4.Clear the Timer0 interrupt flag

Step 5: Call the Delay function go to Step 8

Step 6: Toggle the Port B 3rd pin

Step 7. Repeat the flow from Step 3

Step 8: Start the Timer0

Step 9: Check the Timer0 interrupt flag

Step 10: Repeat the Step 9 until it sets

Step 11: Stop the Timer0

Step 12: Jump to the Step 6

Program for generation of Square waveform

BCF TRISB, 3

MOVLW 0X08

MOVWF T0CON

HERE: MOVLW 0XCF

MOVWF TMR0H

MOVLW 0X2C

MOVWF TMR0L

BCF INTCON, TMR0IF

CALL DELAY

BTG PORTB, 3

BRA HERE

DELAY: BSF TOCON, TMR0ON

AGAIN:BTFSS INTCON, TMR0IF

BRA AGAIN

BCF T0CON, TMR0ON

RETURN