Question

Write an assembly program that toggles a LED connected to pin4 of

PORTB with a custom delay time.

Answer 1

; Main Program

CPL PB4 // compliments value at pin 4 of PORT B

ACALL Wait // calls wait function

SJMP Start

Wait : MOV R4 , #05H // puts value 05H in R4  

Wait1 : MOV R3 , #00H // puts value 00H in R3

Wait2: MOV R2 , #00H //puts value 00H in R2

Wait3 : DJNZ R2,Wait3

DNJZ R3,Wait2

DNJZ R4,Wait1

RET

Hope this helps. If you have any queries or suggestions regarding the answers please leave them in the comments section so I can update and improve the answer. Thank you.