'Directives
DEVICE	 SX28, OSCHS3, TURBO, STACKX, OPTIONX
IRC_CAL  IRC_FAST
FREQ	 50000000
	
		'Pins
StepperCoil1	var	RB.0	OUTPUT	
StepperCoil2	var 	RB.1	OUTPUT
StepperCoil3	var 	RB.2	OUTPUT
StepperCoil4	var	RB.3	OUTPUT 
FIDLEPulse	var 	RB.5	INPUT	'y
SleepSense	Var	RB.6	INPUT	'Always high, unless powered down.


		'Variables
DutyCycle	Var	byte		'range from 1 to 50
PrevStepPos	var	word		'range from 1 to 250 
StepBank	Var	word		
Bank1		Var	byte
Bank2		Var	byte
Bank3		Var 	byte
Bank4		Var 	byte
ContinueBank	Var 	byte
HysteresisVar	Var	byte
RelStepVar	Var	byte

		'Constants
StepCon		Con	5*DutyCycle	'x
Hysteresis	Con	ABS Hysteresis2
Hysteresis2 	Con 	StepBank-PrevStepPos
RelStep		Con	(StepBank-PrevStepPos)
ContinueAddr	Con	5
PrevStepAddr	Con	6
Bank1Addr	Con	1
Bank2Addr	Con	2	
Bank3Addr	Con	3
Bank4Addr	Con	4


		'Main Protocol
PROGRAM Main
Main:
'IF SleepSense=LOW THEN GOSUB ClearCoils		'Resets stepper motor
			'Pause   500			'Pause 500us
 			'GOTO	Main

GOSUB ClearCoils

PULSIN RB.5,1,DutyCycle
GET ContinueAddr,ContinueBank
IF ContinueBank=0 THEN 
GOSUB InitMove
ELSE 
GOSUB HysteresisDet 
ENDIF

GOTO Main

		'Subroutines

InitMove: 
PUT ContinueAddr,1
FOR StepBank = 0 to StepCon
GOSUB ForwardStep
NEXT
PUT PrevStepAddr,StepBank 
GOTO Main



HysteresisDet:
GET PrevStepAddr,PrevStepPos 
LET HysteresisVar = Hysteresis
IF HysteresisVar < 10 THEN 		
GOSUB Pause1				'Hysteresis statement
ELSE 
GOSUB MoveDet 
ENDIF



MoveDet:
PUT Bank1Addr,0
PUT Bank2Addr,0
PUT Bank3Addr,0
PUT Bank4Addr,0
LET RelStepVar = RelStep
IF RelStepVar > 0 THEN  	'RelStep
GOSUB FwdMov 		
ELSE 
GOSUB RvsMov
ENDIF


					
FwdMov:
FOR StepBank = 0 to Hysteresis
GOSUB ForwardStep
NEXT	
GOSUB HoldCoils
PUT PrevStepAddr,StepCon 	'Will this overwrite?				

			     
RvsMov:
FOR StepBank = 0 to Hysteresis
GOSUB ReverseStep
NEXT
GOSUB HoldCoils
PUT PrevStepAddr,StepCon 



Pause1:
PAUSE 	250
GOTO 	Main 



ForwardStep:
GET Bank1Addr, Bank1
	IF Bank1=0 THEN 
	HIGH StepperCoil1
	PUT Bank1Addr,1
	RETURN
	ENDIF
GET Bank2Addr, Bank2
	IF Bank2=0 THEN	
	HIGH StepperCoil2
	PUT Bank2Addr,1
	RETURN
	ENDIF
GET Bank3Addr, Bank3
	IF Bank3=0 THEN 
	HIGH StepperCoil3
	PUT Bank3Addr,1
	RETURN
	ENDIF
HIGH StepperCoil4
PUT Bank1Addr,0
PUT Bank2Addr,0
PUT Bank3Addr,0
RETURN




ReverseStep:
GET Bank4Addr, Bank4
	IF Bank4 = 0 THEN 
	HIGH StepperCoil4
	PUT Bank4Addr,1
	RETURN 
	ENDIF
GET Bank3Addr, Bank3
	IF Bank3 = 0 THEN 
	HIGH StepperCoil3
	PUT Bank3Addr,1
	RETURN 
	ENDIF
GET Bank2Addr, Bank2
	IF Bank2 = 0 THEN 
	HIGH StepperCoil2
	PUT Bank2Addr,1
	RETURN 
	ENDIF
HIGH StepperCoil1
PUT Bank1Addr,0
PUT Bank2Addr,0
PUT Bank3Addr,0
RETURN



HoldCoils: 			
HIGH StepperCoil1 				
HIGH StepperCoil2 				
HIGH StepperCoil3 				
HIGH StepperCoil4 
RETURN



ClearCoils:			'Shutdown routine
LOW StepperCoil1
LOW StepperCoil2 
LOW StepperCoil3 
LOW StepperCoil4 
PUT ContinueAddr,0
RETURN 