ABS operator and "Adress not within lower half of memory page" errors.

Velocit

Hi all,
You'll have to bare with me, as I'm new to both programming and the SX chip. I'm currently running into a few problems while trying to compile my code, and I'd sure appreciate it if someone with more experience could give me a hand.

So, here's the gist of what's going on. I'm trying to write a program that translates the duty cycle of an incoming PWM signal into movement of a bipolar stepper motor. This stepper motor has a range of 0 to X steps, and basically, a 0%DC means the stepper is at position 0, while 100%DC means the stepper is at position X. The relationship is linear, so the rest is easy for the chip to figure out.

Now, the whole thing is coded in SX/B, and I've managed to get rid of all SX/B syntax errors. The only errors I'm encountering are while trying to compile in the converted assembly. It's giving me error codes for "Address not within lower half of memory page" for several of the subroutine labels. I did a little research, but due to my unfamiliarity with the SX assembly language, I couldn't even begin to figure out why it's giving me these errors.

Also, I'm trying to use an absolute value operator, but I don't really know how to implement this. I thought "ABS" could be used in PBASIC, so I assumed it could also be used in SX/B, but the SX-Key software is giving me problems when I try to convert to assembly.

I'm attaching a text file of the SX/B code, and assembly code for anyone who can help to look through. I'm also attaching an "algorithm" of pseudo-code that I wrote to help me make the actual code. It may help you understand what I was aiming for in case my programming is a little convoluted.

Again, I really appreciate any insight you can share with me. I'm new to programming, but I'm really very eager to learn, so your advice will not be wasted. Thanks again!

Bean

Here are some of the problems with the code:

'Directives
DEVICE  SX28, OSCHS3, TURBO, STACKX, OPTIONX
IRC_CAL  IRC_FAST
FREQ  50000000
 

  'Pins   [b][i]***pins must be declared with PIN instead of VAR[/i]
[/b]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 [i][b]***You cannot declare a constant based on a variable[/b]
[/i]StepCon  Con 5*DutyCycle 'x
Hysteresis Con ABS Hysteresis2 ' [i][b]*** SX/B doesn't have ABS[/b][/i]
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

 
[b][i]'*** You need to declare you subroutines here[/i][/b]
[b][i]ClearCoils SUB 0[/i][/b]
[b][i]InitMove SUB 0[/i][/b]
[b][i]HysteresisDet SUB 0[/i][/b]
[b][i]ForwardStep  SUB 0[/i][/b]
 
 
 
  '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 [i][b]'*** You can just use "ContinueBank = ContinueAddr"[/b][/i]
IF ContinueBank=0 THEN 
GOSUB InitMove
ELSE 
GOSUB HysteresisDet 
ENDIF
GOTO Main
 
  'Subroutines
InitMove: 
PUT ContinueAddr,1 [b][i]' *** You can just use "ContinueAddr = 1"[/i][/b]
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

·I would suggest studying the example programs in the help file.

Bean.

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·

Velocit

Thanks so much, Bean!

I really appreciate your help.

Velocit

I just wanted to say thanks again, Bean! Your advice really helped. I got everything to compile successfully now... I'm off to debug the thing and see exactly how well it works with the hardware. Thanks again!