8-bit MicrocontrollersのトピックSimplified Flash Erase and Write Functions for HCS08GT32

Simplified Flash Erase and Write Functions for HCS08GT32

Gcoakley — Wed, 15 Mar 2006 05:48:42 GMT

Hello All,

I am trying to simplify the slfprg-s08gbgt.asm bootloader code to two basic functions: erase and write. So far, I have not had much luck at this and the functions do not appear to change anything in memory. I have attached what I have at the bottom of this posting. Any help would be appreciated. If someone has already done this, could you please post your solution. Thank you.

-gcoakley

EraseFlashPage:
     LDHX    Address
     STHX    ADRS

     lda #(mFPVIOL+mFACCERR) ;mask
  sta FSTAT     ;abort any command and clear errors

  mov  #EraseSubSize, STAT ;length of flash erase routine to STAT
  tsx
  sthx STACK
  ldhx #EraseSubEnd-1   ;point at last byte to move to stack

DoOnStack2:
  lda ,x     ;read from flash
  psha      ;move onto stack
  aix #-1    ;next byte to move
  dbnz STAT, DoOnStack2

EraseSub2:
  ldhx ADRS   ;get flash address
  sta 0,x    ;write to flash; latch addr and data
  lda #mPageErase ;get flash command
  sta FCMD    ;write the flash command
  lda #mFCBEF   ;mask to initiate command
  sta FSTAT    ;[pwpp] register command
  nop      ;[p] want min 4~ from w cycle to r
ChkDoneErase2:
  lda FSTAT    ;[prpp] so FCCF is valid
  lsla      ;FCCF now in MSB
  bpl ChkDoneErase2 ;loop if FCCF = 0

ldhx STACK
txs

rts

WriteFlashPage:
     LDHX Address
     STHX ADRS
     LDA   ALEN                ;load length
     STA   STAT
     STA   LEN
     LDHX #Array              ;load array address
     STHX ADRR

WR_DATA_L2:
     AIX     #1                ;add 1 to index register
     DBNZ    STAT,WR_DATA_L2   ;decrement & branch if not zero

     lda #(mFPVIOL+mFACCERR) ;mask
     sta FSTAT           ;abort any command and clear errors

     mov  #ProgSubSize, STAT ;length of flash prog routine to STAT
   tsx
   sthx STACK
   ldhx #ProgSubEnd-1      ;point at last byte to move to stack

DoOnStack3:
  lda ,x     ;read from flash
  psha      ;move onto stack
  aix #-1    ;next byte to move
  dbnz STAT, DoOnStack3

ProgSub2:
  lda FSTAT    ;check FCBEF
  and #mFCBEF   ;mask it
  beq  ProgSub2   ;loop if not empty

  ldhx ADRR
  lda  0,x
  aix  #1
  sthx ADRR

  ldhx ADRS   ;get flash address
  sta 0,x    ;write to flash; latch addr and data
  aix  #1
  sthx ADRS

  lda #mBurstProg ;get flash command
  sta FCMD    ;write the flash command
  lda #mFCBEF   ;mask to initiate command
  sta FSTAT    ;[pwpp] register command
  dbnz LEN,ProgSub2  ;all bytes in a row?
ChkDoneProg2:
  lda FSTAT    ;[prpp] so FCCF is valid
  lsla      ;FCCF now in MSB
  bpl ChkDoneProg2 ;loop if FCCF = 0

  ldhx STACK
  txs
   rts

Re: Simplified Flash Erase and Write Functions for HCS08GT32

ok2ucx — Thu, 16 Mar 2006 20:30:03 GMT

Hallo,

maybe one little thing overlooked - the Flash module needs (before programming) the proper clock to be programmed - writting into FCDIV register - just like what bootloader does during its initialization:

     LDA    FSTAT
     ORA   #mFACCERR
     STA   FSTAT     ; clear any FACCERR flag

LDA #%00001101 ; div by 13 to fit into 150-200kHz Flash clock!
STA FCDIV

The best (and original) source of these routines is the S08 core reference manual (HCS08RM.pdf if I remember well) available from all S08 summary pages. All details explained there.

Hope it helps,

regards Pavel, ok2ucx (AN2295 developper

Freescale Roznov Labs, Czech Republic EU

Re: Simplified Flash Erase and Write Functions for HCS08GT32

Gcoakley — Fri, 17 Mar 2006 02:06:32 GMT

Thanks Pavel,

I did overlook the clock programming. I will also look at the S08 core reference manual to check and possibly rewrite the code. Thanks again.

-gcoakley

Re: Simplified Flash Erase and Write Functions for HCS08GT32

Gcoakley — Wed, 29 Mar 2006 10:24:27 GMT

Ok, I have done a rewrite of the flash functions and the erase call seems to work perfectly. I am having trouble with the flash writing function however. If I step through or use breakpoints to step through one byte write at a time, the memory locations are written to correctly. But if I execute the code without breakpoints, the memory locations are filled with the character (0x04). This seems like a timing issue, but I am not sure. I am using Pavel's clock setting below to set the clock correctly. Any advice would be appreciated. I have attached the code below.

-gcoakley

prog64:
         LDA   #$40
         STA   $715
   prog64loop:
         LDA   $1825       ;check flash status register
         AND   #$80        ;mask for empty flag
         BEQ   prog64loop

         LDHX $700        ;load source address
         LDA   0,x
         AIX   #1
         STHX $700        ;store new source address+1

         LDHX $705        ;load destination address
         STA   0,x
         AIX   #1
         STHX $705        ;store new destination address+1

         LDA   #$25        ;burst program command
         STA   $1826       ;write command
         LDA   #$80        ;mask to initiate command
         STA   $1825       ;register command

         LDA   $715        ;load loop counter
         DECA              ;decrement counter
         STA   $715        ;save counter
         CMP   #$0
         BNE   prog64loop
   prog64chk:
         LDA   $1825       ;check flash status register
         LSLA
         BPL   prog64chk   ;loop if FCCF = 0
         RTS