STFM (2 ROM): What EEPROM chips are compatible?

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stephen_usher
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STFM (2 ROM): What EEPROM chips are compatible?

Post by stephen_usher » Fri Sep 25, 2020 9:37 am

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.)
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.

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Re: STFM (2 ROM): What EEPROM chips are compatible?

Post by JezC » Fri Sep 25, 2020 10:16 am

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.

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Re: STFM (2 ROM): What EEPROM chips are compatible?

Post by exxos » Fri Sep 25, 2020 10:30 am

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.
https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.

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Re: STFM (2 ROM): What EEPROM chips are compatible?

Post by rubber_jonnie » Fri Sep 25, 2020 11:01 am

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

Otherwise I use exxos' DualTOS adapters.
Collector of old Atari things:
800XL + Ultimate 1MB, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k +APE Warp) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg), 1040STF long button floppy, 2x 1040 STFMs + Gotek, 2x 4160STE with 32Mhz booster, ROM switcher, Mega ST1, Mega ST4, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
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Re: STFM (2 ROM): What EEPROM chips are compatible?

Post by JezC » Fri Sep 25, 2020 11:10 am

rubber_jonnie wrote:
Fri Sep 25, 2020 11:01 am
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)

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Re: STFM (2 ROM): What EEPROM chips are compatible?

Post by rubber_jonnie » Fri Sep 25, 2020 11:27 am

JezC wrote:
Fri Sep 25, 2020 11:10 am
rubber_jonnie wrote:
Fri Sep 25, 2020 11:01 am
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!
Collector of old Atari things:
800XL + Ultimate 1MB, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k +APE Warp) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg), 1040STF long button floppy, 2x 1040 STFMs + Gotek, 2x 4160STE with 32Mhz booster, ROM switcher, Mega ST1, Mega ST4, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

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Re: STFM (2 ROM): What EEPROM chips are compatible?

Post by stephen_usher » Fri Sep 25, 2020 11:46 am

Oh bother! Oh well. No DiagROM for me this weekend then.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.

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Re: STFM (2 ROM): What EEPROM chips are compatible?

Post by JezC » Fri Sep 25, 2020 12:18 pm

rubber_jonnie wrote:
Fri Sep 25, 2020 11:27 am
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:

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Re: STFM (2 ROM): What EEPROM chips are compatible?

Post by rubber_jonnie » Fri Sep 25, 2020 2:04 pm

JezC wrote:
Fri Sep 25, 2020 12:18 pm
rubber_jonnie wrote:
Fri Sep 25, 2020 11:27 am
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......
Collector of old Atari things:
800XL + Ultimate 1MB, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k +APE Warp) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg), 1040STF long button floppy, 2x 1040 STFMs + Gotek, 2x 4160STE with 32Mhz booster, ROM switcher, Mega ST1, Mega ST4, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

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Re: STFM (2 ROM): What EEPROM chips are compatible?

Post by DoG » Fri Sep 25, 2020 2:45 pm

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).

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