#include <p16F690.inc>
     __config (_INTRC_OSC_NOCLKOUT & _WDT_OFF & _PWRTE_OFF & _MCLRE_OFF & _CP_OFF & _BOR_OFF & _IESO_OFF & _FCMEN_OFF)
org 0 
cblock 0x20
TEMP
DISPLAY
DELAY1
DELAY2
W_TEMP
endc
goto          PORTS;
org 0x04
INTERUPT:
	movwf     W_TEMP     ;Store w to TEMP
	bcf       INTCON,7   ; Turn of interupts
	btfss     PIR1,RCIF  ; Wait untill RCREG is full
	goto      $-1
	bcf       PIR1,RCIF  ;Clear flag
	movf      RCREG,w    ; Move RCREG to w
	movwf     DISPLAY    ; Move w to DISPLAY
	call      ROUTINE    
	movf      DISPLAY,w  ; Move DISPLAY to w
	movwf     PORTC      ; Move it to PORTC
	movf      W_TEMP,w   ; Restore w
	bsf       INTCON,7   ; Turn on interupts
	retfie               
ROUTINE:
	bcf      STATUS,0    ;Clear flag
	rlf      DISPLAY     ;Rotate the display
	btfss    STATUS,0    ; Check flag
	return               ; Exit if not set
	movlw    0x01        ; If it is, reset display
	movwf    DISPLAY
	return
PORTS:
	bsf       STATUS,RP1 ;Bank 2
	clrf      ANSEL   ; All pins are digital I/O
 	clrf 	  ANSELH   ; All pins are digital I/O
	bcf       STATUS,RP1 ;Bank 0
	bsf       INTCON,7  ;Set up global interrupts
	bsf       INTCON,6  ; Peripheral Interrupts
	bsf       STATUS,RP0  ;Bank 1
	bsf       PIE1,5      ; Interupt on RX buffer full
	bcf       STATUS,RP0  ; Bank 0
	bcf       PIR1,RCIF   ; Clear the flag
	bsf       STATUS,RP0          ; Bank 1
	movlw     0x00           ; Move the hex value of 0 to multi purpose register W
    movwf     TRISC          ; make IO PortC all output
	movlw     0xff           ; 0xff to w
	movwf     TRISA          ;PORTA input
;serial comm transmit
	movlw     d'25' ; Move the value of 25 or 0x19, to the baud rate genrator
	movwf     SPBRG ; this will make the baud rate = to 9600 at a 4mhz internal clock in high speed mode
	bsf       TXSTA,BRGH   ;baud rate high
	bsf       TXSTA,TXEN   ;Enable Transmision
	bcf       TXSTA,SYNC   ;asyncronous
	bcf       STATUS,RP0 ;Exit bank 1
	;Serial comm Recieve
	bsf       RCSTA,SPEN ;Set serial port enable high
	bsf       RCSTA,CREN ; Enable reciever
	clrf      PORTB     ; Clear 
	clrf      PORTC     ; Clear display
	movlw     0x01      ; Initalize Display
	movwf     DISPLAY
MAIN:
	bsf       PORTC,0   ; Portc high
	btfsc     PORTA,3   ; Poll the button press
	goto      $-1       ; Goto instruction - 1 
	call 	  TX        ; Call transmission
	bcf       PORTC,0   ; Clear port c,0
	call      DELAY     ; Call delay
	goto      MAIN
TX:
	btfss     PIR1 , TXIF  ; TXIF is set if TXREG has no character
 	goto      $-1          ; Loop until TXIF is cleared
 	movf      DISPLAY,w    ; Data to be transmitted over serial port
 	movwf 	  TXREG        ; Copy data to transmit register
 	bsf       STATUS,RP0   ; RAM PAGE 1
	btfss 	  TXSTA , TRMT  ; Wait until transmission is completed
 	goto      $-1          ; Loop back until transmission completed
	bcf       STATUS,RP0
 	return
DELAY:                ; Generic Delay routine
	decfsz   DELAY1
	goto     DELAY
	decfsz   DELAY2
	goto     DELAY
	return
end