;SENIOR DESIGN					CHRIS ANNIS
;TIMER INTERRUPT AND EXTERNAL INTRRUPT
;COUNTS NUMBER OF EXTERNAL INTERRUPTS
;AND DISPLAYS THE COUNT EVERY SECOND

.EQU    COUNT,00H
.EQU    PASS,01H
.EQU	SPEED,02H

	MOV	SPEED,#00H

SJMP    BEGIN

	.ORG    0003H   	;EX0,INTERRUPT SUBROUTINE LOCATION
        LJMP    INTCOU  	;ACTUAL SUBROUTINE FOLLOWS MAIN SECTION
	
;	.ORG    000BH  		;TF0 INTERRUPT SUBROUTINE LOCATION
;	LJMP    INTSPE  	;ACTUAL SUBROUTINEFOLLOWS MAIN SECTION

BEGIN:          		;MAIN SECTION
				;INITIALIZE PASS VALUE
	MOV     PASS,#14H       ;20 PASSES PER SECOND
	MOV     COUNT,#00H	;INITIALIZE COUNT
     	MOV     TMOD,#01H	;SETUP TIMER0, MODE1
       	MOV     TL0,#5AH	;INITIALIZE TIMER0 FOR 5OMSEC DELAY
       	MOV     TH0,#0CBH
       	SETB    TR0		;START TIMER0

	MOV	IE,#83H		;ENABLE EXTERNAL INTERRUPT 0
				;ENABLE TIMER 0 INTERRUPT

;-------FOREGROUND OPERATION
;-------CONTINUOUSLY OUTPUT SPEED TO PORT1

AGIN:   MOV     P1,SPEED
        SJMP    AGIN

;-------INTERRUPT SUBROUTINE
;-------(20 PASSES)


;------TIMER INTERRUPT
;INTSPE: 	
;	DJNZ    PASS,IFIN       ;EXIT IF 1 SEC NOT PASSED
;	MOV	IE,#82H		;DISABLES EXTERNAL INTERRUPT
;        MOV     PASS,#14H       ;RELOAD PASS VALUE
;        MOV	A,SPEED
;	;MOV	SPEED,A
;	INC	SPEED
;	MOV	P1,SPEED
;	;MOV	COUNT,#00H
;IFIN:	MOV     TL0,#5AH        ;REINIT TIMER
;        MOV     TH0,#0CBH
;	MOV	IE,#83H
;        RETI

;------EXTERNAL INTERRUPT-------
INTCOU: 
	MOV	IE,#81H		;DISABLES TIMER INTERRUPT
	MOV	A,COUNT
	ADD	A,#01H		;ADDS 1 TO THE COUNT
	MOV	COUNT,A
	MOV	IE,#83H
	RETI
        
.END