; tuta4.asm
; using	aliases, bit names and conditional loops
        list	p=p16f84
        radix	hex
	include "p16f84.inc"

; high speed >4mhz osc
; disable watchdog timer
	__config _HS_OSC & _WDT_OFF       

#define	page0 bcf STATUS,5
#define	page1 bsf STATUS,5

count	equ 0x0c	; counter storage
ncount	equ 0x0d	; count down storage register
mcount	equ 0x0e	; count down storage register
ocount	equ 0x0f	; count down storage register
shift	equ 0x24	; temporary pattern register	
w	equ 0		; working register flag
f	equ 1		; file register flag
c	equ 0		; carry flag

	org 0		 ; reset vector
	call 5		 ; call start of program
       	org 4		 ; interrupt vector
	call 5		 ; call start of program
       	org 5		 ; start of program memory

       	clrf PORTA	 ; clear port a data register
       	clrf PORTB	 ; clear port b data register

       	page1		 ; page1

       	clrf TRISA	 ; disable port A inputs
       	clrf TRISB	 ; set all port b as output (clear direction reg)

       	page0		 ; page0

        bcf     STATUS,C        ; disable carry flag
        movlw   b'00000001'     ; initial bit pattern
        movwf   shift           ; store pattern

;
; Clockwise Rotation
;
clockw  movf	shift,w		; puts the contents of shift into W
	movwf	PORTB		; puts the contents of W into portb
 	call	pause		; count to 65,000
	clrf	PORTB		; all EL off
        rlf	shift,f		; next EL on
	btfss	STATUS,0	; test carry flag
	goto	clockw		; re-run until carry flag set

;
; Setup bit for reverse function
;
revs	movlw   b'10000000'     ; initial bit pattern
        movwf   shift           ; store pattern

;
; Counter Clockwise Rotation
;
reverse	movf	shift,w		; puts the contents of shift into W
	movwf	PORTB		; puts the contents of W into portb
  	call	pause		; count to 65,000
	clrf	PORTB		; all EL off
        rrf	shift,f		; start from highest bit in portb
	btfss	STATUS,0	; test carry flag
	goto	reverse		; re-run until carry flag set
	movwf	PORTB		; puts the contents of W into portb
  	call	pause		; count to 65,000
	clrf	PORTB		; all EL off

;
; Setup bit for skipen function
;
skipse 	movlw   b'00000001'     ; initial bit pattern
        movwf   shift           ; store pattern

;
; Rotate every even bit including zero in portb
;
skipen	movf	shift,w		; puts the contents of shift into W
	movwf	PORTB		; puts the contents of W into portb
  	call	pause		; count to 65,0000
	clrf	PORTB		; all EL off
	rlf	shift,f 	; skipping a wire with two instructions (1)
	rlf	shift,f 	; skipping a wire with two instructions (2)
	btfss	STATUS,0	; test carry flag
	goto	skipen		; re-run until carry flag set
	movwf	PORTB		; puts the contents of W into portb
  	call	pause		; count to 65,0000
	clrf	PORTB		; all EL off

;
; Rotate every odd bit including zero in portb
;
skipod	movf	shift,w		; puts the contents of shift into W
	movwf	PORTB		; puts the contents of W into portb
 	call	pause		; count to 65,0000
	clrf	PORTB		; all EL off
	rlf	shift,f 	; skipping a wire with two instructions (1)
	rlf	shift,f 	; skipping a wire with two instructions (2)
	btfss	STATUS,0	; test carry flag
	goto	skipod		; re-run until carry flag set
	movwf	PORTB		; puts the contents of W into portb
  	call	pause		; count to 65,0000
	clrf	PORTB		; all EL off

;
; Initialize across bit
;
acrossi	movlw   b'00010001'     ; initial bit pattern
        movwf   shift           ; store pattern
;
; Flash each piece of EL directly across from each other
;
across	movf	shift,w		; puts the contents of shift into W
	movwf	PORTB		; puts the contents of W into portb
  	call	pause		; count to 65,0000
	clrf	PORTB		; all EL off 
	rlf	shift,f 	; skipping a wire with two instructions (2)
	btfss	STATUS,0	; test carry flag
	goto	across		; re-run until carry flag set
	movwf	PORTB		; puts the contents of W into portb
  	call	pause		; count to 65,0000
	clrf	PORTB		; all EL off

;
; flash setup
;
flashs	movlw   b'01010101'     ; initial bit pattern
        movwf   shift           ; store pattern

;
; Flash all of each color 
;
flash	movf	shift,w		; puts the contents of shift into W
	movwf	PORTB		; puts the contents of W into portb
  	call	pause		; count to 65,0000
	clrf	PORTB		; all EL off 
	rlf	shift,f 	; skipping a wire with two instructions (2)
	btfss	STATUS,0	; test carry flag
	goto	flash		; re-run until carry flag set
	goto	clockw		; back to the first function

pause	movlw	0xff 
	movwf	mcount
loadn	movlw	0xff
	movwf	ncount
deco	nop
	nop
	nop
	nop
	nop
	decfsz	ocount,f
	goto	deco
	decfsz	mcount,f
	goto	loadn
	return
end