I am creating some code to save configs in Flash on a HCS908QG8. Single byte writes are fine. I created the code from scratch, but find it is locking-up the micro. I then lifted the code from AN2496 and I get the same result. The problem occurs as soon as I issue the program command.
Any help is appreciated. The code is listed below.
byte_pgm: equ $20 ;Command to program a single byte
; bit position masks
mFCBEF: equ %10000000 ;flash command buffer empty flag
mFCCF: equ %01000000 ;flash command complete flag
mFPVIOL: equ %00100000 ;flash protection violation
mFACCERR: equ %00010000 ;flash access error
mFBLANK: equ %00000100 ;flash verified as all blank (erased =$ff) flag
sei
* Flash Routines Initialisation
lda #!45
sta rFCDIV ;Set the flash clock divider register to produce 186kHz clock
ldhx #vNVStorageStart ;Set up an address pointer
sthx wAddrFlashWrite ; "
lda #'a' ;Create some test data
sta yFlashByte ; "
jsr COP_Reset
ProgFlashByte lda #mFPVIOL|mFACCERR ;error flag bits to clear if set
sta rFSTAT ;clear any error flags
ldhx wAddrFlashWrite ;Get address to program
lda yFlashByte ;Store the byte in flash
sta ,X ; "
aix #1 ;Save address of next free config space in flash
sthx wAddrFlashWrite ; "
lda #byte_pgm ;page write command
sta rFCMD ;initiate the programming sequence
lda rFSTAT
ora #mFCBEF
sta rFSTAT ;launch the command
nop ;burn bus cycs before chking status
nop
nop
nop
nop
lda rFSTAT ;look at status register for errors
and #mFPVIOL|mFACCERR ;error flag bits
bne flash_error ;check for programming errors
pgm_loop: lda rFSTAT ;wait around unil prog'ing complete
and #mFCCF ;command complete yet?
beq pgm_loop ;not done yet..loop until complete
