8051 Assembly Program (Debounced Input)
ORG 0000H
MAIN:
JB P3.2, MAIN ; wait for button press (active LOW)
ACALL DEBOUNCE
CPL P1.0 ; toggle LED
WAIT_RELEASE:
JNB P3.2, WAIT_RELEASE
SJMP MAIN
DEBOUNCE:
MOV R7,#50
D1:
MOV R6,#255
D2:
DJNZ R6,D2
DJNZ R7,D1
RET
END
Button (P3.2): 1
LED (P1.0): 0
LED (P1.0): 0
Hardware Visualization
Port-1 (HEX): 00
Port-3 (HEX): FF
Port-3 (HEX): FF
Concept:
Mechanical switches bounce. The delay routine ensures only a single valid press is detected.
Mechanical switches bounce. The delay routine ensures only a single valid press is detected.