list b=4
;************************************************* *******
;
; step motor control
;
;************************************************* *******

	list p=pic16f84a
	#include <p16f84a.inc>
	__config _HS_OSC & _WDT_OFF & _PWRTE_ON & _CP_OFF
	errorlevel -302 ;Eliminate bank warning

;**************** Label Definition ********************
	cblock h'0c'
mode ;Operation mode
;0=stop 1=right 2=left
count1 ;Wait counter
count2 ;Wait counter(for 1msec)
	endc

rb0 equ 0 ;RB0 of PORTB
rb1 equ 1 ;RB1 of PORTB
rb2 equ 2 ;RB2 of PORTB
rb5 equ 5 ;RB5 of PORTB
rb7 equ 7 ;RB7 of PORTB

;**************** Program Start ***********************
	org 0 ;Reset Vector
	goto init
	org 4 ;Interrupt Vector
	clrf INTCON ;Clear Interruption reg

;**************** Initial Process *********************
init
	bsf		STATUS,RP0 ;Change to Bank1
	clrf	TRISA ;Set PORTA all OUT
	movlw	b'00100111' ;RB0,1,2.5=IN RB7=OUT
	movwf	TRISB ;Set PORTB
	movlw	b'10000000' ;RBPU=1 Pull up not use
	movwf	OPTION_REG ;Set OPTION_REG
	bcf		STATUS,RP0 ;Change to Bank0
	clrf	mode ;Set mode = stop
	clrf	count1 ;Clear counter
	clrf	count2 ;Clear counter
	movlw	b'00000101' ;Set PORTA initial value
	movwf	PORTA ;Write PORTA
	bsf		PORTB,rb7 ;Set RB7 = 1
	btfsc	PORTB,rb5 ;RB5 = 0 ?
	goto	$-1 ;No. Wait

start
;************* Check switch condition *****************
;	btfsc PORTB,rb1 ;RB1(stop key) = ON ?
;	goto check1 ;No. Next
nokeydown
	clrf	mode ;Yes. Set stop mode
	goto	drive ;No. Jump to motor drive
check1
	btfsc	PORTB,rb2 ;RB2(right key) = ON ?
	goto	check2 ;No. Next
	movlw	d'1' ;Yes. Set right mode
	movwf	mode ;Save mode
	goto	drive ;No. Jump to motor drive
check2
	btfsc	PORTB,rb0 ;RB0(left key) = ON ?
	goto	nokeydown ;No. Jump to motor drive
	movlw	d'2' ;Yes. Set left mode
	movwf	mode ;Save mode

;******************** Motor drive *********************
drive
	movf	mode,w ;Read mode
	bz		start ;mode = stop
	bsf		PORTB,rb7 ;Set RB7 = 1
	btfsc 	PORTB,rb5 ;RB5 = 0 ?
	goto 	$-1 ;No. Wait
	movlw 	d'5' ;Set loop count(5msec)
	movwf 	count1 ;Save loop count
loop
	call 	timer ;Wait 1msec
	decfsz	count1,f ;count - 1 = 0 ?
	goto	loop ;No. Continue
	bcf		PORTB,rb7 ;Set RB7 = 0
	btfss	PORTB,rb5 ;RB5 = 1 ?
	goto	$-1 ;No. Wait
	movf	PORTA,w ;Read PORTA
	sublw	b'000000101' ;Check motor position
	bnz		drive2 ;Unmatch
	movf	mode,w ;Read mode
	sublw	d'1' ;Right ?
	bz		drive1 ;Yes. Right
	movlw	b'00001001' ;No. Set Left data
	goto	drive_end ;Jump to PORTA write
drive1
	movlw	b'00000110' ;Set Right data
	goto	drive_end ;Jump to PORTA write
;-------
drive2
	movf	PORTA,w ;Read PORTA
	sublw	b'000000110' ;Check motor position
	bnz		drive4 ;Unmatch
	movf	mode,w ;Read mode
	sublw	d'1' ;Right ?
	bz		drive3 ;Yes. Right
	movlw	b'00000101' ;No. Set Left data
	goto	drive_end ;Jump to PORTA write
drive3
	movlw	b'00001010' ;Set Right data
	goto	drive_end ;Jump to PORTA write
;-------
drive4
	movf	PORTA,w ;Read PORTA
	sublw	b'000001010' ;Check motor position
	bnz		drive6 ;Unmatch
	movf	mode,w ;Read mode
	sublw	d'1' ;Right ?
	bz		drive5 ;Yes. Right
	movlw	b'00000110' ;No. Set Left data
	goto	drive_end ;Jump to PORTA write
drive5
	movlw	b'00001001' ;Set Right data
	goto	drive_end ;Jump to PORTA write
;-------
drive6
	movf	PORTA,w ;Read PORTA
	sublw	b'000001001' ;Check motor position
	bnz		drive8 ;Unmatch
	movf	mode,w ;Read mode
	sublw	d'1' ;Right ?
	bz		drive7 ;Yes. Right
	movlw	b'00001010' ;No. Set Left data
	goto	drive_end ;Jump to PORTA write
drive7
	movlw	b'00000101' ;Set Right data
	goto	drive_end ;Jump to PORTA write
;-------
drive8
	movlw	b'00000101' ;Compulsion setting

drive_end
	movwf	PORTA ;Write PORTA
	goto	start ;Jump to start

;************* 1msec Timer Subroutine *****************
timer
	movlw	d'200' ;Set loop count
	movwf	count2 ;Save loop count
tmlp
	nop				;Time adjust
	nop				;Time adjust
	decfsz	count2,f ;count - 1 = 0 ?
	goto	tmlp ;No. Continue
	return			;Yes. Count end

;************************************************* *******
;
;************************************************* *******

	end