Req:information on in-cart flashrom programing

Req:information on in-cart flashrom programing
by peppers on 2005-10-07 (#5242)

I grow tired of haveing to pull the flashrom each time I need to reprogram them outhers have mentioned some things about programing them in-circuit information on how to go about that would be helpfull

by Memblers on 2005-10-08 (#5288)

I can give you some NES code that works for 29F flashroms if you want it. I've only tested on AMD flashes so far, but other 29xs look the same. I have a subroutine for erasing a sector, and another for programming a byte. Also some code that detects the chip maker/type. All this code has to be copied into RAM and run there.

by peppers on 2005-10-09 (#5304)

well I an currentley useing some Pm29F002T-12PC witch is the 29F020 by PMC I was hopeing i could maybe program them via jtag or something without the cartrige pluged into the nes

by Memblers on 2005-10-09 (#5312)

I couldn't find a datasheet for that chip, but if it's pretty much a normal 29F020 then it'll need something to control all the data and address lines. The NES is the obvious way, maybe also a small circuit could be clipped onto the ROM's pins for programming outside the NES.

If you have to remove the cart from the NES anyways it doesn't seem like a whole lot more work to pull the chip. Though yeah, that's a pain. I have it a little easier with flashes since I use a toploader, and when I had to swap chips I connected the flash to my carts with 2 sockets, that makes it really easy to disconnect.

by peppers on 2005-10-09 (#5315)

alright thanks

would you mind maybe Providing a link or something that goes into greater detail on how to do it with the NES then

btw this is the datasheet I go by it dose not seem to have the 12PC anywhere on there but the pinout the is the same and it seems to be the same thing http://rapidshare.de/files/6091011/PM29F002.pdf.html

by Memblers on 2005-10-09 (#5320)

Here's the erasing and programming code from the Squeedo BIOS.

Of course you also need some way to load the program, I use RS232 (it works ok on the controller port and also through the PIC I use on Squeedo). You also need the /Write signal for PRG from the NES. And well, if there's a mapper at $8000-$FFFF that'll complicate things too.

Code:
sector_erase:
lda #$AA
ldy #$55
ldx #$80

sta $8555
sty $82AA
stx $8555
sta $8555
sty $82AA
lda #$30
sta $8000
:
lda $8000
cmp #$FF
bne :-
rts

byte_program:
stx temp2
ldx #$AA
stx $8555
ldx #$55
stx $82AA
ldx #$A0
stx $8555
sta (ptr),y ;(ptr),y
sta temp_lo

@program_wait:
lda (ptr),y
sta count_lo
lda (ptr),y
sta count_hi
and #%01000000
sta temp3
lda count_lo
and #%01000000
cmp temp3
beq @program_done
lda count_hi
and #%00100000
and count_lo
beq @program_wait
lda (ptr),y
sta count_lo
lda (ptr),y
sta count_hi
and #%01000000
sta temp3
lda count_lo
and #%01000000
cmp temp3
beq @program_done
lda #$F0
sta (ptr),y
ldx temp2
rts

@program_done:
; beep
ldx temp2
rts