Counter with Buttons

Counter with buttons/152120201044.asm

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+    LIST 	P=16F877A
+    INCLUDE	P16F877.INC
+    __CONFIG _CP_OFF &_WDT_OFF & _BODEN_ON & _PWRTE_ON & _XT_OSC & _WRT_ENABLE_OFF & _LVP_OFF & _DEBUG_OFF & _CPD_OFF
+    radix	dec
+
+    ; Reset vector
+    org 0x00
+    
+    ; ---------- Your code starts here --------------------------
+    
+    BSF		STATUS, RP0 ; Select Bank1
+    MOVLW	0xFF
+    MOVWF	TRISB
+    MOVLW	0x00
+    MOVWF	TRISA
+    CLRF	TRISD
+    BCF		STATUS, RP0 ; Select Bank0
+    BSF		PORTA, 5
+      
+    digit_counter	 EQU        0x20
+    NUM			 EQU        0x21
+	 
+    MOVLW	 0
+    MOVWF	 digit_counter 
+  
+    CALL	 Init_NUM
+    CALL         Show_digit
+
+loop:
+        
+button_3:
+    CALL	Delay100ms	    ;Wait for 100 ms before checking the button status again
+    BTFSC	PORTB, 3
+    GOTO	button_4	    ;not press 3
+    GOTO	IncrementCounter    ;press 3
+    
+button_4:
+    BTFSC	PORTB, 4
+    GOTO	button_5	    ;not press 4
+    GOTO	DecrementCounter    ;press 4
+    
+button_5:
+    BTFSC	PORTB, 5
+    GOTO        loop		    ;not press 5
+    GOTO	ResetCounter        ;press 5
+ 
+    
+ResetCounter:                       ;reset counter to 0
+    CALL	Delay100ms
+    MOVLW	0
+    MOVWF	digit_counter 
+    GOTO	Show_digit
+    
+DecrementCounter:                   ;decrement counter
+    CALL	Delay100ms
+    MOVLW	0		   
+    SUBWF	digit_counter, W		   
+    BTFSS	STATUS, Z	   
+    GOTO	not_0
+    MOVLW	9
+    MOVWF       digit_counter       ;0->9
+    GOTO	Show_digit
+not_0:
+    DECF	digit_counter, F
+    GOTO	Show_digit
+    
+IncrementCounter:                   ;increment counter
+    CALL	Delay100ms
+    MOVLW	9		   
+    SUBWF	digit_counter, W		   
+    BTFSS	STATUS, Z	   
+    GOTO	not_9
+    CLRF        digit_counter       ;9->0
+    GOTO	Show_digit
+not_9:
+    INCF	digit_counter, F
+    GOTO	Show_digit
+    
+    
+Show_digit:
+    MOVF	digit_counter, W
+    CALL	GetCode       
+    MOVWF	PORTD
+    GOTO        loop
+    
+    
+GetCode:
+    MOVWF   FSR		; FSR = number
+    MOVLW   NUM		; WREG = &LUT
+    ADDWF   FSR, F	; FSR += &LUT
+    MOVF    INDF, W	; WREG = LUT[number]
+    RETURN
+    
+    
+Delay100ms:
+    i		EQU	    0x70		   
+    j		EQU	    0x71		    
+		
+    MOVLW	    d'100'		    ; 
+    MOVWF	    i			    ; i = 100
+OuterLoop:
+    MOVLW	    d'250'
+    MOVWF	    j			    ; j = 250
+InnerLoop:	
+    NOP
+    DECFSZ	    j, F		    ; j--
+    GOTO	    InnerLoop
+
+    DECFSZ	    i, F		    ; i?
+    GOTO	    OuterLoop    
+    RETURN
+
+	
+    
+Init_NUM:
+    MOVLW   B'00111111'		
+    MOVWF   NUM			; LUT[0] = WREG    
+    MOVLW   B'00000110'		
+    MOVWF   NUM+1		; LUT[0] = WREG    
+    MOVLW   B'01011011'		
+    MOVWF   NUM+2		; LUT[0] = WREG    
+    MOVLW   B'01001111'		
+    MOVWF   NUM+3		; LUT[0] = WREG    
+    MOVLW   B'01100110'		
+    MOVWF   NUM+4		; LUT[0] = WREG    
+    MOVLW   B'01101101'		
+    MOVWF   NUM+5		; LUT[0] = WREG    
+    MOVLW   B'01111101'		
+    MOVWF   NUM+6		; LUT[0] = WREG    
+    MOVLW   B'00000111'		
+    MOVWF   NUM+7		; LUT[0] = WREG    
+    MOVLW   B'01111111'		
+    MOVWF   NUM+8		; LUT[0] = WREG    
+    MOVLW   B'01101111'		  
+    MOVWF   NUM+9		; LUT[0] = WREG  
+    RETURN
+  
+    
+    ; ---------- Your code ends here ----------------------------    
+    MOVWF   PORTD    	; Send the result stored in WREG to PORTD to display it on the LEDs
+    
+LOOP    GOTO    $	; Infinite loop
+    END