;****************************************************************
;
; I/O practise with push buttons input and LED output
;
; Using AT89C2051 with 12MHz Osc Crystal
;
; All Port 3 pins are used for push button input
;
; All Port 1 pins are used for LED output, low active
;
;*****************************************************************

ORG 00H										; set origin of memory

MOV SP, #5FH									; set stack point, start at 60H

MOV TMOD, #01H									; set timer 0 to 16 bit mode

MOV P1, #0FFH									; turn off all LEDs

ORL P3, #0FFH									; set P3 ready to read input

		
START:		MOV P1, #0FEH						; turn on LED at Port 1 LSB
			CALL WAIT500						; delay for 0.5 second
			MOV P1, #0FFH						; turn off Port 1 LSB LED
			CALL WAIT500						; delay for 0.5 second
			AJMP START



WAIT500:	MOV R0, #10						; loop counter 10 to delay 10 x 50ms = 0.5s
LOOP:		MOV TH0, #HIGH (-49990)			; set high byte of timer 0 to delay 50ms
			MOV TL0, #LOW (-49990)				; set low byte of timer 0 to delay 50ms	

			JB P3.0, PATTERN0					; if button at P3.0 pressed
			JB P3.1, PATTERN1					; if button at P3.1 pressed
			JB P3.2, PATTERN2					; if button at P3.2 pressed
			JB P3.3, PATTERN3					; if button at P3.3 pressed
			JB P3.4, PATTERN4					; if button at P3.4 pressed
			JB P3.5, PATTERN5A					; if button at P3.5 pressed
			JB P3.7, PATTERN7A					; if button at P3.7 pressed

CARRYON:	CLR TF0							; reset timer 0 overflow flag
			SETB TR0							; start timer 0
			JNB TF0, $							; do nothing and wait for timer 0 overflow
			CLR TR0							; stop timer 0
			DJNZ R0, LOOP						; loop for 10 times
			RET



WAIT20:		MOV TH0, #HIGH (-20000)				; delay for 20ms
			MOV TL0, #LOW (-20000)
			CLR TF0
			SETB TR0
			JNB TF0, $
			CLR TR0
			RET

PATTERN0:	CALL WAIT20						; wait for 20ms
			JNB P3.0, CARRYON					; if unpressed after 20ms, false alarm, carry on
			JB P3.0, $							; wait indefinitely until button released
			
LOOP0:		MOV P1, #00H						; turn on all P1 LEDs
			CALL WAIT500						; wait for 0.5 second
			MOV P1, #0FFH						; turn off all P1 LEDs
			CALL WAIT500						; wait for 0.5 second
			SJMP LOOP0							; always performing pattern 0 flashing
			

PATTERN1:	CALL WAIT20						; wait for 20ms
			JNB P3.1, CARRYON					; if unpressed after 20ms, false alarm, carry on
			JB P3.1, $							; wait indefinitely until button released

LOOP1:		MOV P1, #0FH
			CALL WAIT500						; wait for 0.5 second
			MOV P1, #0F0H
			CALL WAIT500						; wait for 0.5 second
			SJMP LOOP1							; always performing pattern 0 flashing



PATTERN5A: AJMP PATTERN5						; stations for instruction jump to avoid out of range error
PATTERN7A: AJMP PATTERN7
CARRYONA: AJMP CARRYON







PATTERN2:	CALL WAIT20						; wait for 20ms
			JNB P3.2, CARRYON					; if unpressed after 20ms, false alarm, carry on
			JB P3.2, $							; wait indefinitely until button released
			
			MOV A, #01H
LOOP2:		MOV P1, A
			CALL WAIT500
			RL A
			SJMP LOOP2


PATTERN3:	CALL WAIT20						; wait for 20ms
			JNB P3.3, CARRYON					; if unpressed after 20ms, false alarm, carry on
			JB P3.3, $							; wait indefinitely until button released
			
			MOV A, #10000000B
LOOP3:		MOV P1, A
			CALL WAIT500
			RR A
			SJMP LOOP3


PATTERN4:	CALL WAIT20						; wait for 20ms
			JNB P3.4, CARRYON					; if unpressed after 20ms, false alarm, carry on
			JB P3.4, $							; wait indefinitely until button released
			
LOOP4:		MOV P1, #11100111B
			CALL WAIT500
			MOV P1, #11011011B
			CALL WAIT500
			MOV P1, #10111101B
			CALL WAIT500
			MOV P1, #01111110B
			CALL WAIT500
			SJMP LOOP4


CARRYONB:	AJMP CARRYON



PATTERN5:	CALL WAIT20						; wait for 20ms
			JNB P3.5, CARRYONA					; if unpressed after 20ms, false alarm, carry on
			JB P3.5, $							; wait indefinitely until button released
			
LOOP5:		MOV P1, #01111110B
			CALL WAIT20
			CALL WAIT20
			MOV P1, #00111100B
			CALL WAIT20
			CALL WAIT20
			MOV P1, #00011000B
			CALL WAIT20
			CALL WAIT20
			MOV P1, #00000000B
			CALL WAIT500
			MOV P1, #0FFH
			CALL WAIT500

			MOV P1, #11100111B
			CALL WAIT20
			CALL WAIT20
			MOV P1, #11000011B
			CALL WAIT20
			CALL WAIT20
			MOV P1, #10000001B
			CALL WAIT20
			CALL WAIT20
			MOV P1, #00000000B
			CALL WAIT500
			MOV P1, #0FFH
			CALL WAIT500
			SJMP LOOP5

PATTERN7:	CALL WAIT20						; wait for 20ms
			JNB P3.7, CARRYONB					; if unpressed after 20ms, false alarm, carry on
			JB P3.7, $							; wait indefinitely until button released
			
LOOP7:		MOV P1, #00000000B
			CALL WAIT500
			MOV P1, #10000000B
			CALL WAIT500
			MOV P1, #11000000B
			CALL WAIT500
			MOV P1, #11100000B
			CALL WAIT500
			MOV P1, #11110000B
			CALL WAIT500
			MOV P1, #11111000B
			CALL WAIT500
			MOV P1, #11111100B
			CALL WAIT500
			MOV P1, #11111110B
			CALL WAIT500
			MOV P1, #11111111B
			CALL WAIT500
			SJMP LOOP7


END