Need help identifying rom chip

Posted by Glass-Potential7483@reddit | vintagecomputing | View on Reddit | 24 comments

I'm not sure if this is a PROM or EEPROM, and I can't find the pinout/datasheet for it. Chip is from an old S3 Trio64V2/DX PCI GPU. Any help would be greatly appreciated!

p.s. The markings on the bottom say:

7B1245-3

4003B

1-F 7B9747

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TrekChris@reddit

Video BIOS for an S3 Trio64 graphics card.

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Glass-Potential7483@reddit (OP)

I know that, I just need the pinout to dump it

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AustriaModerator@reddit

remove the sticker. its literally written onto the chip itself.

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Glass-Potential7483@reddit (OP)

Yeah, thats what i ended up doing

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sidusnare@reddit

What, really? Pin 1 is the bottom left corner in this picture, if you have a reader, it really should have a ZIF socket with a similar marker for pin 1.

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Glass-Potential7483@reddit (OP)

I figured it out, its an AT27C256R. Sadly its an OTP Eprom, so I cant rewrite it.

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tomasvala@reddit

Just get EEPROM AT27C256 or W27C256 or some other compatible and program it.

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ceojp@reddit

I wouldn't overwrite the original chip anyway! Just get some blank chips and use those. You can probably find a pin-compativle flash variant.

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TechCF@reddit

Easily enough to replace with an eprom. I flashed and overclocked some of these cards.

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Gadgetman_1@reddit

The information is most likely under the label. But odds are that it's a PROM chip as those are cheaper than EEPROMs

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The cost difference wasn't big enough for long to overcome the burden of discarding chips when upgrades /patches were unavoidable. Eventually most people moved to EEPROM so they didn't have to choose between discarding palates of cards or the labor intensive process of discarding chips and installing new ones. With an EEPROM, you can just send out a patch floppy and let the customer upgrade the card.

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Gadgetman_1@reddit

This card is from 1996. Firmware upgrades weren't really a thing on those back then. And BIOS upgrades on PCs was something you only did if you really, really needed it.

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sidusnare@reddit

I was repairing PCs in the 90s, probably installed a few of these cards brand new, we did flashed ROMs all the time, and I was who people called when they really really needed it.

My shop even had one of those over priced ROM writers the size of a camp stove wtih all kinds of ZIF sockets on it and a LPT port on the side to do the kind of flashing that couldn't be done in situ.

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Hardin4188@reddit

For home or office use? So does that mean you can't use that at school or on vacation?

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LittlePooky@reddit

HIS (Hightech Information System): This is the company that manufactured the actual physical circuit board (the video card itself). HIS is a hardware manufacturer founded in Hong Kong in 1987, best known in later years for producing AMD Radeon graphics cards.

S3 (S3 Graphics): This was the company that designed and manufactured the actual graphics processor chip. During the 1990s, S3 was one of the most dominant and respected manufacturers of 2D graphics chips in the world.

Trio64V2: This is the specific model of the chip, released in 1996. It is a 64-bit graphics processor. The "V2" usually came in two variants: the Trio64V2/DX (which used standard DRAM or EDO RAM) and the Trio64V2/GX (which used faster SDRAM or SGRAM). +2

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sidusnare@reddit

To be clear, the pictured chip is not the graphics chip. Pictured is a CMOS chip that would have, and perhaps still does, hold the video BIOS. These are standard parts, and with the right hardware you could back up the video BIOS abd share it, perhaps on archive.org, or reflash it with anything, it could become a motherboard BIOS, or an XT/IDE in a NIC card option ROM socket.

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