Error : overwrite same program counter location

loojade · 2008-02-21 13:16

Hallo everybody

I nebie with SXB and I don't know assembly... I write a program and it seems correct, but when I try to run it some errors appear.
The main problem is that the errors are in assembly code (geneterd by SX KEY I think).

This is my SXB code :

[code]

'

' Program Description
'

'
' GRIPOne

Bean · 2008-02-21 13:29

You cannot declare SUBs before the INTERRUPT command.
Do this:

' -------------------------------------------------------------------------
INTERRUPT 50_000
  GOTO ISR_Start
' -------------------------------------------------------------------------

 
' -------------------------------------------------------------------------
' Subroutine Declarations
' -------------------------------------------------------------------------

CHECK_SPINNING  SUB     0                       ' 
MEM_OUT         SUB     3                       ' write value to memory
MEM_IN          SUB     2                       ' read byte from memory

' -------------------------------------------------------------------------

ISR_Start:

Ch1:

You have some problems in your code though. For example from within the interrupt routine you are using "GOTO Check_Spinning", but that is a subroutine. If you really just want to call the Check_Spinning subroutine, just use "Check_Spinning" without the goto.

Bean.

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·

loojade · 2008-02-21 14:48

Thanks Bean,

You are very kind and fast to reply...
I'll try like you show me.
I change the position of SUB declaration because If I try to put it after the INTERRUPT code, it was impossible call the SUB.
But like this should be ok.

Thanks again

Loojade

loojade · 2008-02-25 21:44

I change a bit the the code but compiling the same eror appeare...
"overwriting same program location"
and to the next row: "address exceeds memory limit"

this is the SXB code:

[code]

'

' Program Description
'

'
' GRIPOne

JonnyMac · 2008-02-25 22:46

You have very large interrupt structure -- you might consider trimming that down. Another strategy, often used by forum guru PJV, is to simply let the ISR mark a flag that the foreground waits for; once the flag has been detect the foreground program can go forward with a large chuck of code (so long as it's not so large that the flag gets reset before the code is done).

pjv · 2008-02-26 05:34

Hi Jonny;

Actually, things can be simply improved if the flag is replaced by a counter (as in my more recent examples), and the foreground simply tests it for a non-zero value, then proceeds with the foreground code (as it did with the flag), and decrements the counter by one. If, on completing the foreground task, the counter still is not zero, perhaps because it took longer than one interrupt tick, the foreground program is again immediately launched with another round, repeating all this until the couner is empty.

In this manner, no ticks are lost, regardless (almost) of the size of the foreground program. At worst a bit of jitter is introduced.

Interrupt······· ·inc········· Intcounter··················· ;indicate another interrupt has occurred
···················· mov······ ·w, #IntValue··············· ·;return to main or scheduler
···················· retiw

Scheduler······ test·········IntCounter··················· ;test for non-zero
····················snz
··················· jmp········ Scheduler···················· ·;no tick is detected
··················· dec·········IntCounter···················· ;subtract one interrupt event
··················· scheduler code··························· ·;scheduler and application code as per "flag" examples
··················· .
··················· .
··················· scheduler code
··················· jmp······· Scheduler······················ ·;wait for another interrupt

Cheers,

Peter (pjv)

Post Edited (pjv) : 2/26/2008 5:41:52 AM GMT

JonnyMac · 2008-02-26 15:09

That's a cool idea, Peter, thanks for sharing.

loojade · 2008-02-27 16:47

Actually I'm not sure to understud...

But I change a lot the program. JonnyMac spoken about lot of code in interrupt so I change the code. Now I use the asichro interrupt to fix the counter
and the main program to INC the counter:


...
ISR_Start:
  WKPND_B = winner                            ' get winner
    byte_interrupt = winner
Ch1:                                                ' check channel
    IF byte_interrupt <> %00000001 THEN Ch2             ' if not, try next
    last_fr_l = counter_fr_l                        'quando l'ingresso cambia di stato salvo il valore del contatore  e azzero il contatore
    last_fr_h = counter_fr_h
    counter_fr_l = 0
    counter_fr_h = 0
    GOTO ISR_Exit

Ch2:
    IF byte_interrupt <> %00000010 THEN Ch3             ' if not, try next
    last_rr_l = counter_rr_l                        'quando l'ingresso cambia di stato salvo il valore del contatore  e azzero il contatore
    last_rr_h = counter_rr_h
    counter_rr_l = 0
    counter_rr_h = 0
    GOTO ISR_Exit

Ch3:
  IF byte_interrupt <> %00000100 THEN ISR_Exit
    IF controllo = 1 THEN
        IF cicli < taglio THEN
            IF cicli = 0 THEN
                t_control = 1
            ELSE
                t_control = 0
            ENDIF
            INC cicli
            IF cicli = taglio THEN
                cicli = 0
            ENDIF
        ENDIF
    ENDIF
  GOTO ISR_Exit

ISR_Exit:
  WKEN_B = %11111000                            ' prepare for new ISR

  RETURNINT
...

[code]

...
Start:
WKPND_B = %00000000 ' clear pending
WKED_B = %11111111 ' falling edge detect
WKEN_B = %11111000 ' use bits 0..2 for inputs

TRIS_B = %00011111 ' imposto gli ingressi e le uscite della porta B
TRIS_C = %00000000 ' imposto gli ingressi e le uscite della porta C

INPUT SDA ' float I2C bus pins
INPUT SCL

counter_fr_l = 255
counter_fr_h = 255
counter_rr_l = 255
counter_rr_h = 255
last_fr_l = 255
last_fr_h = 255
last_rr_l = 255
last_rr_h = 255
controllo = 0
byte_interrupt = 0
addr = 0
byte1 = 0

Main:

IF button_1 = 1 THEN 'il pulsante di scelta

Error : overwrite same program counter location

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