ASM code

[Bill Legge]

Charles,

Thanks, I will have a go at doing the work with DT's interrupts - I'm pretty sure that you are correct.

I wanted to use my own ASM to:

1. Learn more about ASM
2. Learn more about MPLAB and debugging.
3. Learn how to glue ASM into PBP.

The most useful things learnt over the last few days were:

1. Debugging ASM with interrupts in it.
2. After a quickish look at DT's interrupt code I think I may now be able to follow it.

I'd much appreciate your input on getting the code on this thread to run in PBP. Despite playing with 'org' and so on, I keep getting lots of:

overwrite previous address contents error

Regards Bill Legge

[mackrackit]

I'd much appreciate your input on getting the code on this thread to run in PBP. Despite playing with 'org' and so on, I keep getting lots of:

overwrite previous address contents error

Regards Bill Legge

You must be trying to set the configuration fuses more than once.
In the PBP part of the code?
In the ASM part?
In the *.inc file?
http://www.picbasic.co.uk/forum/showthread.php?t=543

[Charles Linquis]

Again -

I think you would be FAR better off if you would just use Darrel's code as a starting point. Since you have two priorities, you need to put the following in your DEFINE block.

DEFINE USE_LOWPRIORITY 1


Then use Darrel's INCLUDE files as needed.

INCLUDE "DT_INTS-18.bas" ; Base Interrupt System
INCLUDE "ReEnterPBP-18.bas" ; Include if using PBP interrupts
INCLUDE "ReEnterPBP-18LP.bas" ; Include if using Low Pr. PBP INTS



Then define your variables in PBP. If you have enough space, you can define all of them as BankA SYSTEM. If you don't, make certain that you define all the ones that you want to pass between PBP and ASM as bankA System

The variables will be case-sensitive.


Set up all timer prescalers, clock sources and triggering edges first.


Now put in Darrel's interrupt control block -
Change the labels as necessary.

ASM

INT_LIST  macro    ; IntSource,        Label,  Type, ResetFlag?
              INT_Handler    TMR0_INT,   SystemTimer,   ASM,  yes 
              INT_Handler    RX1_INT,    _GetCharPort1,    PBP,  yes
              endm
    INT_CREATE               ; Creates the interrupt processor

INT_LIST_L  macro  ; IntSource,        Label,  Type, ResetFlag?
           INT_Handler     PIC_YOUR_INT,        StepperControl, ASM,no
    endm
    INT_CREATE_L             ; Creates the Low Priority interrupt processor

ENDASM

                         
Goto OverInt
------------------------------------------
ASM

(Put all your ASM ISR code here)

@ INT_RETURN
ENDASM
 -------------------------------------------
[Put all your PBP ISR code here]


@ INT_RETURN

---------------------------------------------

Overint:

(Clear INT flags)


@ INT_ENABLE (name of INT)
@ INT_ENABLE (name of other INT)
@ INT_ENABLE (name of other INT)

NothingLoop:


 Goto NothingLoop  ; do nothing until you get an int.

Hopefully, I haven't forgotten something. !

Doing things this way will not only likely get you to a running program much faster, it will make it easier for others to give you the help you need. After all, this IS a PBP forum, not an ASM forum.

[Bruce]

Hi Bill,

I like to encourage everyone to learn assembly, and how to handle interrupts. Where would we be here if DT never learned assembly or interrupts...;o)

Here's a simple modified version of what you had. Look at the changes I made VS your original. I could point to every single change,
but it wouldn't help you learn much.

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

   LIST P=18F8722           ; Directive to define processor
   #include "P18F8722.inc"  ; Drocessor specific variable definitions
	
;******************************************************************************
;  Configuration bits
   CONFIG  OSC = HSPLL  ; Run at 4X speed
   CONFIG  CP0=OFF      ; Disable code protect				
   CONFIG  PWRT = OFF   ; Power up timer off so DEBUG works            
   CONFIG  WDT=OFF      ; WDT off
   CONFIG  LVP = OFF    ; LVP off
   CONFIG  WAIT = OFF   ; External bus data wait disabled
;******************************************************************************
;  Variable definitions in data memory
  CBLOCK 0x0000  ; all in ACCESS RAM
    Count_pulse  ; Loop delay in 5 uS pulse to motor driver
    X_delay : 2  ; Inter-pulse delay for X axis, 2 bytes
    Y_delay : 2  ; Inter-pulse delay for Y axis, 2 bytes
    X_steps : 2  ; Number of steps to do on X axis, 2 bytes
  ENDC

;******************************************************************************
;  Reset vector in program memory
   ORG    0x0000
   goto   Main_ASM ; Go to start of main code
;******************************************************************************
;  All interrupts vector to here, Priorities disabled
   ORG    0x0008
   bra    Tmr_ints  ; Go to interrupt routine
;******************************************************************************
;******************************************************************************
;  Higher priority for Timer0 overflows, send out stepper
;  drive pulse for X axis on PORTD.0
Tmr_ints
   btfss  INTCON,TMR0IF    ; did Timer0 interrupt?
   bra    LowPri           ; no. branch to Timer1 int
   bsf    PORTD,0          ; yes. High PORTD.0
   call   Pulse_out        ; Send 5uS pulse on PORTB.0
   bcf    PORTD,0          ; Low PORTD.0  (Timer1 interrupts around here)
   bcf    INTCON,TMR0IF    ; Clear Timer0 interrupt flag
   movff  X_delay+1,TMR0H  ; Load timer0 with X_delay high byte
   movff  X_delay,TMR0L    ; Load timer0 with X_delay low byte
   movf   X_steps,W        ; load WREG for compare after subtraction
   decf   X_steps,F        ; Decrement X_steps low byte
   cpfslt X_steps          ; if X_steps < WREG then jump over next decrement
   decf   X_steps+1        ; else, decrement high byte
                            
;  Lower priority for Timer1 overflows, send out stepper
;  drive pulse for Y axis on PORTD.3
LowPri
   btfss  PIR1,TMR1IF      ; Timer1 int pending?										
   bra    IntExit          ; no. exit
   bsf    PORTD,3          ; High PORTD.3
   call   Pulse_out        ; Delay for 10 microseconds
   bcf    PORTD,3          ; High PORTD.3
   bcf    PIR1,TMR1IF      ; Clear Timer1 interrupt flag
   movff  Y_delay+1,TMR1H  ; Load Timer1 with Y_delay high byte
   movff  Y_delay,TMR1L    ; Load timer1 with Y_delay low byte
IntExit
   retfie FAST             ; return & restore WREG, STATUS, BSR
	
;******************************************************************************                                                                           *
;                               SUBROUTINES                                   *                                                                            * 
;******************************************************************************
	
Pulse_out              ; Delay = 3.n + 7 [0.1 microseconds]
   movlw   0xff        ; Load w with n
   movwf   Count_pulse ; Load Count with n
Pulse_loop
   decfsz  Count_pulse ; Decrament the file Count
   goto    Pulse_loop  ; Loop if not zero
   return
	
;******************************************************************************                                                                           *
;                                  MAIN ASM                                   *                                                                             * 
;******************************************************************************
	
Main_ASM	
   clrf	  TRISA  ; PORTA is output
   clrf   TRISB  ; PORTB is output
   clrf   TRISC  ; PORTC is output
   clrf	  TRISD  ; PORTD is output
   clrf	  TRISE  ; PORTE is output
   clrf	  TRISF  ; PORTF is output
   clrf	  TRISG  ; PORTG is output
   clrf	  TRISH  ; PORTH is output
   clrf	  TRISJ  ; PORTJ is output
	
   clrf	  PORTA  ; Clear PORTA
   clrf	  PORTB  ; Clear PORTB
   clrf	  PORTC  ; Clear PORTC
   clrf	  PORTD  ; Clear PORTD
   clrf	  PORTE  ; Clear PORTE
   clrf	  PORTF  ; Clear PORTF
   clrf	  PORTG  ; Clear PORTG
   clrf	  PORTH  ; Clear PORTH
   clrf	  PORTJ  ; Clear PORTJ

   movlw  0x0f
   movwf  ADCON1  ; PORTA is digital I/O
   movlw  0x07
   movwf  CMCON   ; Comparator off
	
; Set up interrupt conditions for Timer0 and Timer1	
   bcf    RCON,7     ; disable priority levels on interrupts,IPEN=0
   bsf    INTCON,7   ; Enable all interrupts
   bsf    INTCON,6   ; Enable all peripheral interrupts
   bcf    INTCON,3   ; Disable PORTB interrupts
   bcf    INTCON2,2  ; Make Timer0 overflow low priority
   bcf    IPR1,0     ; Make Timer1 overflow low priority
   bsf    INTCON,5   ; Enable Timer0 overflow int
   bsf    PIE1,0     ; Enable Timer1 overflow int		
	
; Set up Timer0 conditions				
   bcf    T0CON,6    ; Timer0 uses 16 bits
   bcf    T0CON,5    ; Timer0 uses internal osc
   bcf    T0CON,4    ; Timer0 count on rising edge og osc
   bsf    T0CON,3    ; Timer0 pre-scaler not assigned
   clrf   TMR0H      ; Zero the clock
   clrf   TMR0L      ; Zero the clock				
   bsf    T0CON,7    ; Timer0 on
		
; Set up Timer1 conditions
   bsf    T1CON,7    ; Timer1 uses 16 bits
   bcf    T1CON,1    ; Timer1 uses internal osc
   clrf   TMR1H      ; Zero the clock
   clrf   TMR1L      ; Zero the clock
   bsf    T1CON,0    ; Timer1 on	
	
; Temp code to simmulate PBP input for the delays
   clrf   X_delay    ; this handles the low byte
   clrf   X_delay+1  ; this handles the high byte
   clrf   Y_delay
   clrf   Y_delay+1
   clrf   X_steps
   clrf   X_steps+1					
;  End of Temp code	

; Check if X_steps_lb=0 (decremented in high priority interrupt)
; If so, check X_steps_hb and if zero, end
; If not, decrement X_steps_hb, set X_steps_lb and go again	
Main_loop
   movff   X_steps+1,PORTC ; high byte to portc
   ;btg     PORTC,1         ; toggle RC1 (note: comf only works with whole 8-bit registers)
   movff   X_steps,PORTD   ; low byte to portd
   ;btg     PORTD,1         ; toggle RD1
   tstfsz  X_steps         ; Test, skip next if zero
   goto    Main_loop       ; More steps to do, so loop
   tstfsz  X_steps+1       ; Test, skip next if zero
   bra     Re_load_lb
   goto    All_done
	
Re_load_lb
   decf    X_steps+1,F  ; Decrement hb and then carry to lb
   setf    X_steps      ; Decremented hb, so load ff to lb
   goto    Main_loop
	
All_done	
   bcf     INTCON,7      ; Clear GIE, disable ALL interrupts
   clrwdt
   sleep
   goto    $-2
   end

I think you're much better off putting both interrupts in the same handler, and just checking for which one caused the interrupt VS having a high pri interrupt your low pri, so you can use the auto restore for W, STATUS & BSR.

[Bill Legge]

Bruce,

Wow, what a lot of effort on your part - thanks very much. I will now re-fire up MPLAB and give it a detailed run.

I do take note of CL's comments about this being a PICBASIC site but most entheuastic PBP users will want to experiment with ASM - for fun and speed?

I know that every minuit I've spent on ASM in MPLAB had added greatly to my ability to write software in PBP.

Perhaps there is space for an 'ASM' sub-section in this forum? I can understand that most newcomers will not be interested in this lower level stuff but it seems essential to make the most of PBP.

We are in the middle of a heatwave here in West Australia - almost no rain for 3 months - too hot to do much outside so plenty of key-board time.

Thanks again for your input.

Regards Bill Legge

[Charles Linquis]

My goal was not to discourage ASM use (I use a lot of it myself), but only to point out that DT_INTs would make things easier for you. And since a lot of people on this forum are familiar with their use, a lot more people would be able to help you if you chose that route.

[Bill Legge]

Charles & Bruce,

Thanks for your help.

Bruce: the code you provided works well and I've tested it in MPLAB with a variety of inputs and it's all OK.
I have 'glued it into PBP and still can't get it to compile. The things I changed between the ASM_only and PBP_ASM are:

1. Deleted the .asm CONFIGS because they come from my programmer.
2. Deleted the .asm variable definitions in data memory, defined them in PBP, watched out for caes sensitivity and changed the .asm definitions to have a leading underscore (e.g. _X_steps).