; -------------------  Function Description  ------------------- 
; The interrupt output on the Key-unit is connected to the input 
; for external interrupt 2 on P1.4. A LED in the LED-unit is   
; connected to P4.0 to provide a visual indication of the 
; interrupt initiated by pressing a key.
; --------------------------------------------------------------



; --------- Declarations required for the Assembler ----------
            CPU     80515           ; Select microcontroller
            INCLUDE STDDEF51        ; SFR definitions


            SEGMENT Code            ; Code segment starts here
            ORG     0000H           ; 1st. instruction, starts at address 0000H
; -------------------------------------------------------------
            jmp   START             ; Jump to main program
; -------------------------------------------------------------



; --------------- Enter the IV in the IVT ---------------------
            ORG   004BH             ; IV-position for external interrupt 2
            JMP   ISR_INT2          ; Interrupt vector (IV)
; -------------------------------------------------------------


; *************************************************************
; *       Main program, "Ext.Interrupt 2 from pressing a key  *
; *************************************************************
START:
            CALL  INIT_INT2         ; Initialise ext. Interrupt 2
            


; ***********************************************************
;                                          y  d
; ***********************************************************

	MOV     A,#11111111B            ; Define bit pattern 
	MOV     P1,A                    ; Bit pattern to Port 1
	JB	P4.3, ST7
	JMP     START
	
ST7:	JB      P4.7, ST6               ; pushnutton P4.7 for CW
      	CPL 	P1.6
        JMP	ST1    	


ST6:	JB      P4.6, ST7		; pushnutton P4.6 for ccw
	CPL 	  P1.7
	JMP	    ST2 	

; CW
				
; ...........................................................
ST1:	JB	     P4.3, ST20		; fault - switch off P4.3	
	JMP           START


ST20:	JB	    P4.5, ST15		; pushbutton STOP P4.5
	JMP 	    START

ST15:	JB	    P4.4,  ST1		; pushbutton START  P4.4
	MOV     A,#10111110B 
	MOV     P1,A 
	CALL 	    TIMER2
	CALL	    TIMER2
	MOV     A,#10111010B 
	MOV     P1,A 
	CALL 	    TIMERD
	CPL 	    P1.0

	CALL 	    TIMER2
	CALL	    TIMER2

ST3:	MOV     A,#10111001B
	MOV     P1,A 	
	JB	    P4.3, ST11 		; fault - switch off P4.3		
	JMP      ST13  


ST11:	JB	    P4.5, ST3		; pushnutton STOP P4.5
	
ST13:	MOV     A,#10111111B
	MOV     P1,A
	CALL 	    TIMER2
	CALL	    TIMER2
	JMP    START   
	


;CCW
 
	                
; ..........................................................

ST2:		JB	     P4.3, ST21		; fault switch off P4.3	
		JMP           START



ST21:    	JB	    P4.5, ST16 		; pushnutton STOP P4.5
		JMP 	    START


ST16:  		JB	    P4.4,  ST2		; tipkalo START  P4.4

	MOV     A,#01111110B 
	MOV     P1,A 
	CALL	    TIMER2
	CALL	    TIMER2
	MOV     A,#01111010B 
	MOV     P1,A 

	CALL 	    TIMERL
	CPL 	    P1.0
	CALL 	    TIMER2
	CALL	    TIMER2

ST4:	MOV     A,#01111001B
	MOV     P1,A 
	
	JB	P4.3, ST12			;  fault - switch off P4.3
	JMP    ST14  
	
T12:	JB	  P4.5, ST4			;  pushnutton STOP P4.5

ST14:	MOV     A,#01111111B
	MOV     P1,A
	CALL 	    TIMER2
	CALL	    TIMER2

	JMP    START      
	
; *********************************************************


     
; ----------------------------------------------------------
; 
TIMERD:  

		MOV     R1,#200        		; Counter for outer loop
DELAY1:	MOV 	    R2, #200		
DELAY2:	MOV         R3, #50
DELAY3:	DJNZ	R3, DELAY3

		JB	     P4.3, ST31		; fault - switch off P4.3	
		JMP ST70

ST31:    	JB	    P4.5, ST45		; pushnutton STOP P4.5
		
ST70:		MOV     A,#01111111B
		MOV     P1,A
		CALL 	    TIMER2
		CALL	    TIMER2
		JMP           START
		
ST45:		DJNZ     R2, DELAY2
		DJNZ     R1, DELAY1
		
	RET                     
; ----------------------------------------------------------

TIMERL:  

		MOV    	 R1,#100        	; Counter for outer loop
DELAY4:	MOV 	    R2, #200
DELAY5:	MOV         R3, #50
DELAY6:	DJNZ	R3, DELAY6

		JB	     P4.3, ST51		; fault - switch off P4.3	
		
		JMP ST80


ST51:    	JB	    P4.5, ST65		; pushbutton STOP P4.5
		
ST80:		MOV     A,#01111111B
		MOV     P1,A
		CALL 	    TIMER2
		CALL	    TIMER2
		JMP           START
		
ST65:		DJNZ     R2, DELAY5
		DJNZ     R1, DELAY4
		
	RET                     



TIMERINTERUPT:  

		MOV    	 R1,#100        	; Counter for outer loop

		
DELAY7:	MOV 	    R2, #250	
		    CPL   P4.0

DELAY8:	MOV         R3, #200

DELAY9:	DJNZ	    R3, DELAY9
     
		
		JB	     P4.3, ST61		; fault switch - off P4.3			
		JMP ST82


ST61:    	JB	    P4.5, ST75		; pushnutton STOP P4.5
		
ST82:		MOV     A,#11111111B
		MOV     P1,A

ST75:		DJNZ     R2, DELAY8
		DJNZ     R1, DELAY7		
		
	RET  

; ----------------------------------------------------------
;       Sub Routine , approx. 131ms
; ----------------------------------------------------------
; 2 nested DJNZ loops
TIMER2:  MOV     R7,#000H        ; Counter for outer loop
Z01:    MOV     R6,#000H        ; Counter for inner loop
Z00:    DJNZ    R6,Z00          ; 256*2µs (inner loop)
	DJNZ    R7,Z01          ; 256* inner loop
	RET                     
; ----------------------------------------------------------

            JMP   $                 ; Endless loop as "End"
                                    ; of the main program
; *************************************************************

; -------------------------------------------------------------
;    Sub-routine for initialising external Interrupt 2
; -------------------------------------------------------------
INIT_INT2:
            CLR   EAL               ; Global inhibit of interrupt acceptance
            SETB  I2FR              ; 0-1 edge initiates interrupt
            SETB  EX2               ; Allow interrupt from ext.Int 2
            SETB  EAL               ; Allow interrupt acceptance, global
            RET
; -------------------------------------------------------------
;                   ISR for ext. Interrupt 2
; -------------------------------------------------------------
ISR_INT2:
           
		CALL     TIMERINTERUPT           
           	CLR   IEX2              ; Reset interrupt request bit (*)
		
		JB   P1.5, ST77          ; P1.5 ACKNOWLEDGE
		JMP ST78
ST77:   	PUSH   0000H
ST78:           RETI       	

            
; -------------------------------------------------------------

END