M912 with 1 MB cache \ VOGONS

M912 with 1 MB cache

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First post, by demiurge

Posted on 2024-03-21, 03:38

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In order to not necro another thread I need to know if a few of these questions have been answered in a decade::

feipoa wrote on 2011-06-02, 05:50:

A better question might be, has anyone had success with any PCI-based 486 motherboard and 1 MB of L2 cache?

I got a Chips M912 to run a UMC Green 40 and can't get the second bank of cache to work for 1024kB. The chips all check fine in the first bank and swapped them over to the second. So everything works fine at 512 kB but just says "waiting" after memory test. The AMI BIOS will load (because it is before cache I guess) set for 1024 kB but letting the boot go will lock the machine at the "waiting...". The jumpers are correctly set and the board will boot just fine if set for 512 kB.

I can't find any trace damage and this looks like a great board but this one issue is stopping me from loving it.

Before I completely discard this board, is there something I should try?

Reply 1 of 11, by BitWrangler

Posted on 2024-03-21, 04:05

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I don't know if there's been enough of us running UMC CPU to full characterise the compatibility envelope, so I'd say to test with an Intel DX to see if it's a UMC specific thing or not.

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Reply 2 of 11, by Nexxen

Posted on 2024-03-21, 04:26

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demiurge wrote on 2024-03-21, 03:38:

Before I completely discard this board, is there something I should try?

As suggested, test with other cpus.
Update BIOS. Maybe look for some beta specific to this issue.

https://theretroweb.com/motherboards/?name=m912

PC#1 Pentium 233 MMX - 98SE
PC#2 PIII-1Ghz - 98SE/W2K

Reply 3 of 11, by demiurge

Posted on 2024-03-21, 11:27

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BitWrangler wrote on 2024-03-21, 04:05:

I don't know if there's been enough of us running UMC CPU to full characterise the compatibility envelope, so I'd say to test with an Intel DX to see if it's a UMC specific thing or not.

Same problem with an Intel DX2 installed

Reply 4 of 11, by Nexxen

Posted on 2024-03-21, 14:07

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demiurge wrote on 2024-03-21, 11:27:

BitWrangler wrote on 2024-03-21, 04:05:

I don't know if there's been enough of us running UMC CPU to full characterise the compatibility envelope, so I'd say to test with an Intel DX to see if it's a UMC specific thing or not.

Same problem with an Intel DX2 installed

What's your bios version?
Could you post a pic of your board?

PC#1 Pentium 233 MMX - 98SE
PC#2 PIII-1Ghz - 98SE/W2K

Reply 5 of 11, by demiurge

Posted on 2024-04-20, 23:49

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So I was using 128kx8 DIP modules for cache as well as the tag. The manual specifies a 64x8 DIP for tag, could this be the cause? I though I could always use a bigger tag than needed.
However, once again, the 128kx8 tag works for tag in 512kB mode and that only needs a 32x8, so I don't know.

The BIOS version is 40-E300-001437-00111111-121593-GREEN-H date: 07/08/1994 and if I need to flash it can someone recommend a tool to do that?

There also seems to be some weirdness going on, but that could be the I/O controller.

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Reply 6 of 11, by Nexxen

Posted on 2024-04-21, 11:36

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demiurge wrote on 2024-04-20, 23:49:
So I was using 128kx8 DIP modules for cache as well as the tag. The manual specifies a 64x8 DIP for tag, could this be the cause […]
Show full quote

So I was using 128kx8 DIP modules for cache as well as the tag. The manual specifies a 64x8 DIP for tag, could this be the cause? I though I could always use a bigger tag than needed.
However, once again, the 128kx8 tag works for tag in 512kB mode and that only needs a 32x8, so I don't know.

The BIOS version is 40-E300-001437-00111111-121593-GREEN-H date: 07/08/1994 and if I need to flash it can someone recommend a tool to do that?

There also seems to be some weirdness going on, but that could be the I/O controller.

The exact version of your board is written next to the keyboard connector.
My guess is ver 1.4, and there are newer bios versions available.

As a tool you probably need a software, try https://theretroweb.com/drivers/75
If it doesn't work probably your bios chip is not flashable and need a new one.

Edit:

your jp10 is set to 1-2, not 2-3
jp12 should be capped
I can't see if jp5 is correctly populated, 2-3 / 4-5 / 6-7

Ok, it's 512K of L2. Picture is blurry.
Well, try updating the bios.

PC#1 Pentium 233 MMX - 98SE
PC#2 PIII-1Ghz - 98SE/W2K

Reply 7 of 11, by demiurge

Posted on 2024-04-21, 13:50

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Nexxen wrote on 2024-04-21, 11:36:
The exact version of your board is written next to the keyboard connector. My guess is ver 1.4, and there are newer bios version […]
Show full quote

demiurge wrote on 2024-04-20, 23:49:
So I was using 128kx8 DIP modules for cache as well as the tag. The manual specifies a 64x8 DIP for tag, could this be the cause […]
Show full quote

So I was using 128kx8 DIP modules for cache as well as the tag. The manual specifies a 64x8 DIP for tag, could this be the cause? I though I could always use a bigger tag than needed.
However, once again, the 128kx8 tag works for tag in 512kB mode and that only needs a 32x8, so I don't know.

The BIOS version is 40-E300-001437-00111111-121593-GREEN-H date: 07/08/1994 and if I need to flash it can someone recommend a tool to do that?

There also seems to be some weirdness going on, but that could be the I/O controller.

The exact version of your board is written next to the keyboard connector.
My guess is ver 1.4, and there are newer bios versions available.

As a tool you probably need a software, try https://theretroweb.com/drivers/75
If it doesn't work probably your bios chip is not flashable and need a new one.

Edit:

your jp10 is set to 1-2, not 2-3
jp12 should be capped
I can't see if jp5 is correctly populated, 2-3 / 4-5 / 6-7

Ok, it's 512K of L2. Picture is blurry.
Well, try updating the bios.

I already tried using uniflash but I think the 486s need a external machine to do it.

Reply 8 of 11, by Nexxen

Posted on 2024-04-21, 15:08

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demiurge wrote on 2024-04-21, 13:50:

I already tried using uniflash but I think the 486s need a external machine to do it.

If you have a spare bios try using that.
PCChips used write once chips.

I have a TL-886+, used it so many times it basically paid off for itself over and over again.
There is a newer version with a ton of adapters, but it's like 70€

PC#1 Pentium 233 MMX - 98SE
PC#2 PIII-1Ghz - 98SE/W2K

Reply 9 of 11, by majestyk

Posted on 2024-04-21, 15:24

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It could be some Mask-ROM with a forged AMI sticker 🙁
Is the chip made of ceramic or plastic?

...if it´s not troublesome, it´s simply not PC-Chips.

Reply 10 of 11, by Nexxen

Posted on 2024-04-21, 15:33

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majestyk wrote on 2024-04-21, 15:24:

It could be some Mask-ROM with a forged AMI sticker 🙁
Is the chip made of ceramic or plastic?

...if it´s not troublesome, it´s simply not PC-Chips.

PC-Chips could be one of the companies in Fallout... 🤣

PC#1 Pentium 233 MMX - 98SE
PC#2 PIII-1Ghz - 98SE/W2K

Reply 11 of 11, by Anonymous Coward

Posted on 2024-04-21, 17:08

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Did you check to see that the manufacturer actually connected all the address lines to the cache sockets?

"Will the highways on the internets become more few?" -Gee Dubya
V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium

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