Hi,
here is at most one big mistake:
the MOVFW at end of the ISR is definitely bogus as it destroys the Z flag.
All of PIC data sheets contain a correct suggestion how to deal with IT's
(e. g. DS30390-B, p. 136)

I hope this is a contribution.
Imre


On Wed, 3 Feb 1999, Bart Stofferis wrote:

> > Hi there !!
> >
> > Name here is Bart, and i have got some problems with my LUTs (lookup
> > tables) & PIC16C73A or 16C76.
> >
> > I have to implement 10 tables of 127 bytes and the problem is that
> > when an interrupt occurs the
> > program counter jumps somewhere in space ... lost in space ...
> >
> > I don't understand the program counter mechanism very well ...
> >
> > Can someone reserve some time to have a look at my experiments
> >
> > I have included 2 files, the main program file and the LUT-file
> >
> > Thanks a lot ... and enjoy !
> >
> >
> > Main Program:
> > -----------------------
> >
> >       list p=16C76                  ; select controller
> >       include "P16C76.INC"            ; include this file where
> >                                       ; all initialisation of
> > Registers
> >                                       ; are defined.
> >
> >       __CONFIG        _HS_OSC&_WDT_OFF&_PWRTE_OFF;
> >
> >
> > pointadres    equ     0x020
> > pointvalue    equ     0x021
> > WBACKUP               equ     0x022
> > WBACKUPINT    equ     0x023
> > STATUSBACKUPINT       equ     0x024
> >
> > ;+++++++++++++++++++++++++++++++++++++++++++++++++++
> > GoSub MACRO Subrtn
> > ; Performa "call subroutine" anywhere in memory.
> > ;+++++++++++++++++++++++++++++++++++++++++++++++++++
> >       movwf   WBACKUP
> >       movlw   HIGH Subrtn
> >       movwf   PCLATH
> >       movfw   WBACKUP
> >       call    Subrtn
> >       movwf   WBACKUP
> >       movlw   HIGH $
> >       movwf   PCLATH
> >       movfw   WBACKUP
> >       ENDM
> >
> > Startup
> >
> >       org     0x000
> >       goto    Init            ; reset vector address
> >
> >       org     0x004           ; interrupt vector address
> >       goto    ServiceInt
> >
> >       org     0x010
> > Init
> >       movlw   0x000           ; pointerwaarden 0..127
> >       movwf   pointadres
> >
> >       bsf     STATUS,RP0      ; PAGE1
> >       bcf     STATUS,RP1      ; PAGE1
> >       movlw   0x000           ; PAGE1
> >       movwf   TRISB           ; PAGE1
> >       movwf   TRISC           ; PAGE1
> >       movlw   0x007           ; PAGE1
> >       movwf   OPTION_REG      ; PAGE1
> >       bcf     STATUS,RP0      ; PAGE1
> >       bcf     STATUS,RP1      ; PAGE1
> >
> >       clrf    TMR0
> >       movlw   0x0E0
> >       movwf   INTCON
> >
> >
> > Main
> >       movfw   pointadres      ;1
> >       GoSub   M_ONTime
> >       movwf   PORTB
> >
> >       movfw   pointadres      ;2
> >       GoSub   L_ONTime
> >       movwf   PORTB
> >
> >       movfw   pointadres      ;3
> >       GoSub   M_PWM
> >       movwf   PORTB
> >
> >       movfw   pointadres      ;4
> >       GoSub   L_PWM
> >       movwf   PORTB
> >
> >       movfw   pointadres      ;5
> >       GoSub   M_MSB
> >       movwf   PORTB
> >
> >       movfw   pointadres      ;6
> >       GoSub   L_MSB
> >       movwf   PORTB
> >
> >       movfw   pointadres      ;7
> >       GoSub   M_Mid
> >       movwf   PORTB
> >
> >       movfw   pointadres      ;8
> >       GoSub   L_Mid
> >       movwf   PORTB
> >
> >       movfw   pointadres      ;9
> >       GoSub   M_LSB
> >       movwf   PORTB
> >
> >       movfw   pointadres      ;10
> >       GoSub   L_LSB
> >       movwf   PORTB
> >
> >       goto    Main
> >
> >
> >       include "e:\firmware\hbtable.h"
> >
> > ; ServiceInt
> > ServiceInt
> >       movwf   WBACKUPINT
> >       movfw   STATUS
> >       movwf   STATUSBACKUPINT
> >       btfss   INTCON,T0IF
> >       goto    ServiceIntEnd
> > Timer0Int
> >       bcf     STATUS,RP0
> >       bcf     INTCON,T0IF
> >       bsf     PORTC,7
> >       clrf    TMR0
> >       bsf     INTCON,T0IE
> >
> > ServiceIntEnd
> >       movfw   STATUSBACKUPINT
> >       movwf   STATUS
> >       movfw   WBACKUPINT
> >       retfie
> >
> >       END
> >
> > Table file:
> > -----------------
> >
> > ;filename HBTABLE.H
> > ;
> > ; LOOK-UP Table definition
> > ;
> > ; ON_Time     adres
> > ;  M_ONTime     1600
> > ;  L_ONTime     1700
> > ;
> > ; PWM_Freq
> > ;  M_PWM        1800
> > ;  L_PWM        1900
> > ;
> > ; 24bconv
> > ;  M_MSB        1A00
> > ;  L_MSB        1B00
> > ;  M_Mid        1C00
> > ;  L_Mid        1D00
> > ;  M_LSB        1E00
> > ;  L_LSB        1F00
> > ;
> > ;*********************************************************************
> > ********
> >
> >
> >
> >
> > ;*********************************************************************
> > ********
> > ;
> > ; LOOK-UP Table ON_Time
> > ;
> > ;*********************************************************************
> > ********
> >
> >
> >       org     0x1600
> >       de      "M_ONTime",0
> >
> > M_ONTime              ; High part ON_Time
> >       addwf   PCL,f
> >
> >       retlw   0x001
> >       retlw   0x019
> >
> >       *****127 values*****
> >
> >       org     0x1700
> >       de      "L_ONTime",0
> >
> > L_ONTime              ; Low part ON_Time
> >       addwf   PCL,f
> >
> >       retlw   0x002
> >       retlw   0x032
> >
> >       *****127 values*****
> >
> >
> >
> >       org     0x1800
> >       de      "H_PWM   ",0
> >
> > M_PWM                 ; High part PWM frequency
> >       addwf   PCL,f
> >
> >       retlw   0x004
> >       retlw   0x04B
> >
> >       *****127 values*****
> >
> >
> >       org     0x1900
> >       de      "L_PWM   ",0
> >
> > L_PWM                 ; Low part PWM frequency
> >       addwf   PCL,f
> >
> >       retlw   0x008
> >       retlw   0x064
> >
> >       *****127 values*****
> >
> >
> >       org     0x1A00
> >       de      "M_MSB   ",0
> >
> > M_MSB                 ; High part MSB 24bit word
> >       addwf   PCL,f
> >
> >       retlw   0x001
> >       retlw   0x07D
> >
> >       *****127 values*****
> >
> >
> >       org     0x1B00
> >       de      "L_MSB   ",0
> >
> > L_MSB                 ; Low part MSB 24bit word
> >
> >       addwf   PCL,f
> >
> >       retlw   0x002
> >       retlw   0x096
> >
> >       *****127 values*****
> >
> >
> >       org     0x1C00
> >       de      "M_Mid   ",0
> > M_Mid                 ; High part Mid 24bit word
> >
> >       addwf   PCL,f
> >
> >       retlw   0x004
> >       retlw   0x0AF
> >
> >       *****127 values*****
> >
> >
> >       org     0x1D00
> >       de      "L_Mid   ",0
> >
> > L_Mid                 ; Low part Mid 24bit word
> >       addwf   PCL,f
> >
> >       retlw   0x008
> >       retlw   0x0C8
> >
> >       *****127 values*****
> >
> >
> >       org     0x1E00
> >       de      "M_LSB   ",0
> >
> > M_LSB                 ; High part LSB 24bit word
> >       addwf   PCL,f
> >
> >       retlw   0x001
> >       retlw   0x0E1
> >
> >       *****127 values*****
> >
> >
> >       org     0x1F00
> >       de      "L_LSB   ",0
> >
> > L_LSB                 ; Low part LSB 24bit word
> >       addwf   PCL,f
> >
> >       retlw   0x002
> >       retlw   0x0FA
> >
> >       *****127 values*****
> >
> >
> > Tnx ! , Bart
> >
>
>