Have you tried simulating the code.

Sometimes the mistake you cannot see in the code pops up in a simulator.

It should be easy to fill the buffer with values from 0 to 63 and
write the buffer to verify that all the values appear where they are
supposed to.

Is the chip receiving and buffering the data properly. This can be
verified by reading the buffer back after writing.


cheers

Tony



On Sun, Oct 9, 2016 at 10:19 AM, IVP <joecolquitt@clear.net.nz> wrote:
> Hi all,
>
> I'm having trouble getting a routine to write data where I think it
> should. I've not done any Flash writing for a long time so probably
> missing something pretty obvious. I've checked the d/s and had a
> look around for examples and can't spot anything
>
> The routine receives a packet of 48 bytes and writes it to an address
> defined by the value of a two-digit LED display. For example, if the
> display is showing 09, then the 48 bytes should be written to the block
> starting at (9*64) + 0x1800, where 0x1800 is the base address
>
> What I'm getting though is a write only when display =3D 00 and only
> to the block address in the set-up declaration, eg t_data =3D 0x1800
>
> If I change t_data to 0x1840, it will write there. And explicitly setting
> TBLPTR in the code doesn't make a difference. The blk_add routine
> returns the correct value for TBLPTR, the code seems to ignore it
>
> If 0x1840 is the intended target (dg =3D 1, t_data =3D 0x1800), the write
> will happen only if I clear it with 0000 data statements in the program,
> otherwise the locations will stay as FFFF. But that write does miss the
> first byte. All 48 bytes are correct when dg=3D00
>
> Below is the section of code
>
> Can anyone see what's missing ? I'm sure there's a common cause for
> what's happening
>
> TIA
>
> Joe
>
> ------------------
>
> mov      macro   val,file
>          movlw   val
>          movwf   file
>          endm
>
> t_data =3D 0x1800
>
> ;multiply digits by 64 to find block, add t_data base
> ;
> ;eg
> ;digits =3D 23 in <temp1:temp0> =3D 05c0, + 1800 =3D 1dc0
>
> ;Erase block
> ;Write buffer48 to block
>
> wr_block movff   buffer,postinc0 ;last byte received
>
> ;         movlw   .0              ;display value, manual test
> ;         movwf   dg01
> ;         movlw   .0
> ;         movwf   dg10
>
>          call    blk_add         ;get block start address
>
> ;         clrf    tblptru         ;Flash block address, manual test
> ;         movlw   0x18
> ;         movwf   tblptrh
> ;         movlw   0x40
> ;         movwf   tblptrl
>
> ;Block command can resolve to 8 bytes
> ;Erase command can resolve to 64 bytes (x00,x40,x80,xc0 starts)
>
> ;Erase block
>
> erase    bcf     eecon1,cfgs     ;erase block
>          bsf     eecon1,eepgd
>          bsf     eecon1,wren
>          bsf     eecon1,free
>          bcf     intcon,gie
>          mov     0x55,eecon2
>          mov     0xaa,eecon2
>          bsf     eecon1,wr
>          nop
>          tblrd*-
>
> ;write RAM to Flash as 64-byte (8*8) block
>
>          mov     .8,bitcnth      ;'8-bytes' counter
>          lfsr    fsr1,buffer48   ;data to write
>
> write    mov     .8,bitcntl      ;byte counter
>
> copy8    movff   postinc1,tablat ;copy 8 bytes to write buffer
>          tblwt*+
>          decfsz  bitcntl         ;byte counter
>          bra     copy8
>
>          mov     0x55,eecon2
>          mov     0xaa,eecon2
>          bsf     eecon1,wr
>          nop
>          decfsz  bitcnth         ;8-byte counter
>          bra     write
>          bcf     eecon1,wren
>
>          goto    wait            ;done
>
> ;=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>
> ;Get Flash address from dg10:dg01, tens:units, 00d-30d
>
> blk_add  rlncf   dg10,w          ;combine dg10:dg01
>          rlncf   wreg
>          rlncf   wreg            ;(dg10 * 8) + (dg10 * 2)
>          addwf   dg10,w
>          addwf   dg10,w
>          addwf   dg01,w          ;+ dg01
>          movwf   temp1           ;temp1 =3D (dg10 * 10) + dg01
>          clrf    temp0
>
>          clrc                    ;* 64
>          rrcf    temp1
>          rrcf    temp0
>          rrcf    temp1
>          rrcf    temp0
>
>          clrc                    ;add 0x1800 base address
>          movlw   low(t_data)
>          addwf   temp0
>          movlw   high(t_data)
>          addwfc  temp1
>
>          clrf    tblptru         ;Flash block address
>          movff   temp1,tblptrh
>          movff   temp0,tblptrl
>
>          return
>
>
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