exxos's Atari, Amiga & retro forum

I've been searching on-line this morning and can't seem to get a straight answer to the question:

What EEPROM models are pin compatible with the sockets on a STFM (2 ROM) motherboard?

(Background: I need to make a pair of DiagROM-ST ROMs.)

Not quite the answer to your question...but the TF DiagROM image will fit in a pair of 27512 EPROMS.

There are a few Microchip OTP EPROMS in 28 pin packages - Farnell has a few for example, including 512kbit.
So, if the pinout matches, they might be an option.

2 ROM's nope, none. Only 32pin EPROMS which you have to bodge fit.

EDIT:
This is why I sell dualtos boards. Some others on here have some EPROM adapters which should fit more layouts. I think it was @DoG who did some.

TBH I have a pile of 27C256s and just fit an extra 4 sockets :)

Otherwise I use exxos' DualTOS adapters.

rubber_jonnie wrote: 25 Sep 2020 11:01 TBH I have a pile of 27C512s and just fit an extra 4 sockets :)

Otherwise I use exxos' DualTOS adapters.

Don't you only need 6x 27C256 for 6 ROMs? That gives you all 192k of ROM decode space...

Anyway...if TF's build of DiagROM is good enough that will just for into 2x 27C512 (after you trim off the 'junk' at the end of each image)

JezC wrote: 25 Sep 2020 11:10

rubber_jonnie wrote: 25 Sep 2020 11:01 TBH I have a pile of 27C512s and just fit an extra 4 sockets :)

Otherwise I use exxos' DualTOS adapters.

Don't you only need 6x 27C256 for 6 ROMs? That gives you all 192k of ROM decode space...

Indeed, I meant to write 27C256 and wrote 27C512 because my brain is addled at the moment! D' oh

Corrected!

Oh bother! Oh well. No DiagROM for me this weekend then.

rubber_jonnie wrote: 25 Sep 2020 11:27 Indeed, I meant to write 27C256 and wrote 27C512 because my brain is addled at the moment! D' oh

Know that feeling all too well :lol: especially when our kitten decides to have a mad half hour at 2:30 AM!
zzzzzzzzzzz...sorry, must have dozed off there :roll:

JezC wrote: 25 Sep 2020 12:18

rubber_jonnie wrote: 25 Sep 2020 11:27 Indeed, I meant to write 27C256 and wrote 27C512 because my brain is addled at the moment! D' oh

Know that feeling all too well :lol: especially when our kitten decides to have a mad half hour at 2:30 AM!
zzzzzzzzzzz...sorry, must have dozed off there :roll:

I feel ya, except our kitten is a 6 year old cat......

If you got 2 ROM board you should be able to move 3 solderblobs and use 6 27C256 instead. Just split DIAGROM into 6 pieces. Otherwise you can use 2 32pin 27C010 and some wire to mod the 2 EPROMs to use DIAGROM on that. You don't need a pcb mod board but it for sure will be neater. I made some and I wrote it in my blog a while ago. Works as a normal 28-32 pin adapter (with ROM switch for 4 ROMs and external chip enable/select signal for decoder board).