Chapter 4 Timer Operation

By: Masud-ul-Hasan

Ex4-3: 1 kHz Square Wave

Write a program using Timer 0 to create a 1 kHz square wave on P1.0.

ORG 0000H

MOV TMOD, #01H ;16-bit mode

LOOP: MOV TH0, # FEH ;T= 1/1kHz=1000µs

MOV TL0, # 0CH ;-500=FE0CH

SETB TR0 ;start timer

WAIT: JNB TF0, WAIT ;wait for overflow

CLR TR0 ;stop timer

CLR TF0 ;clear overflow flag

CPL P1.0 ;toggle port bit

SJMP LOOP ;repeat

END