Newer 1998 BIOS for PC Chips M5x series?

bizzybody · BIOS Rookie Joined: 20 Oct 2007 Posts: 36

I have an M535 board with UMC IO chip, flashed with a M520 BIOS with the release date of 12/07/98

ID string =
PC Chips M520 (Rel. 1.1A)
12/07/98-i430VX-2A59GHTBC-00

Is this actually newer than the 10/17/97-i430VX-02271997C-00 on http://wims.rainbow-software.org/index.php?count=-1 ?

The original ID string was 10/16/96-i430X-10031996C-00 I couldn't find any M535 BIOS anywhere, but did find a few things saying the M520 BIOS would work, and it does, except for POST saying it's an M520.

If someone wants this BIOS to do stuff to, I'll be happy to send it. How can I tell if it's the L or S type?

edwin · Posted: Fri Nov 02, 2007 9:11 am Post subject:

that is the last bios released. It is S-type so if your board still lives you have an S-type bios. Unsure if this has harddisk support >32GB.

Usually you can see this in the release <some date code>S
release <some date code>L on the startup screen.
_________________
edwin/evasive

Do not assume anything

System error, strike any user to continue...

KachiWachi · Posted: Fri Nov 02, 2007 11:42 am Post subject:

The patched BIOS does have support for >32GB.

Thanks.
_________________
CPU - DFI 586IPVG, K6-2/+ 450 (Cyrix MII 433), i430VX, 128MB EDO.
BIOS patched by BiosMan (Jan Steunebrink).

bizzybody · BIOS Rookie Joined: 20 Oct 2007 Posts: 36

How can I find out if the 1998 BIOS has any improvements (like CPU support) over the patched 1997 BIOS, or if the 1998 BIOS already supports drives over 32gig?

I don't have a 32 to 64 gig drive to test it, but I do have a noisy 13gig Maxtor to check it for the 8gig limit.

BiosMan · Posted: Sat Nov 03, 2007 1:41 pm Post subject:

I've looked into the M520 12/07/98 BIOS and it seems to have IDE HDD support up to 32GB.
CPU support includes the K6-2 and K6-III up to 400MHz but Write-Allocation support is limited to the K6 and original K6-2. So no WA for the K6-2CXT and K6-III, and the K6-2+ and K6-III+ are not supported at all. Surprised

The BIOS is patchable for 128GB and extented AMD support. Let us know what you need! Wink

Jan.
_________________
The Unofficial AMD K6-2+ / K6-III+ page
http://web.inter.nl.net/hcc/J.Steunebrink/k6plus.htm

KachiWachi · Posted: Sat Nov 03, 2007 2:16 pm Post subject:

I was going to ask you to do this at one time, but I found out that my Amptron PM 7900 (M520 clone) has a short in the VCore - V I/O circuit...so I cannot power a split-plane CPU. Sad

I even bought a VRM module too. Sad

I'd still be interested in this at some point...if and when I can find the short.

Thanks.
_________________
CPU - DFI 586IPVG, K6-2/+ 450 (Cyrix MII 433), i430VX, 128MB EDO.
BIOS patched by BiosMan (Jan Steunebrink).

bizzybody · BIOS Rookie Joined: 20 Oct 2007 Posts: 36

edwin · Posted: Sun Nov 04, 2007 9:22 am Post subject:

cp · Posted: Sun Nov 04, 2007 10:18 am Post subject:

i have several vrm boards. they are all using simple pwm controllers like this:
http://focus.ti.com/lit/ds/symlink/ucc3800.pdf

the circuit is basically the same as this one:
http://focus.ti.com/lit/an/slua185/slua185.pdf

btw. PCChips boards are often using this:
http://www.onsemi.com/pub/Collateral/MC34063A-D.PDF

i could try to make a circuit with the MC34063A, too..if someone is interested.

edwin · Posted: Sun Nov 04, 2007 11:17 am Post subject:

Just as an exercise alone that would be fun I think. The main thing is the VRM socket layout unless that is completely standardized?
_________________
edwin/evasive

Do not assume anything

System error, strike any user to continue...

KachiWachi · Posted: Sun Nov 04, 2007 1:01 pm Post subject:

@edwin -

The VCore and V I/O planes are shorted together internally...so that pretty much kills using a VRM untill I can separate them (somehow).

I bought an HP VRM (switching type) that will run a 233MMX...but I indended to modify it to run other CPU's (resistor selection).

Thanks.
_________________
CPU - DFI 586IPVG, K6-2/+ 450 (Cyrix MII 433), i430VX, 128MB EDO.
BIOS patched by BiosMan (Jan Steunebrink).

cp · Posted: Sun Nov 04, 2007 2:25 pm Post subject:

VRM layout is standardized:

http://www.tec.ufl.edu/~jhavar/pentium_processor_motherboard.pdf

@KachiWachi: can you send a picture of the mainboard? maybe we can find out how to separate the planes.

you can btw. request free samples of the UCC3803D at:
http://focus.ti.com/docs/prod/folders/print/ucc3803.html#samples

KachiWachi · Posted: Mon Nov 05, 2007 2:36 pm Post subject:

@cp -

How would a picture help?

The only place VCore is *supposed* to go is to the CPU.

On these boards, four jumpers are inserted into the VRM slot when a single plane CPU is installed. Pulling the jumpers separates the planes from +3.3V so that the VRM can do its thing.

When I pull the jumpers, the planes are not isolated from each other (ohm check)...hence a short *must* be present internally in the motherboard...or a solder splash exists under the CPU socket (which I cannot see).

(Note - CPU is removed for the ohm check.)
_________________
CPU - DFI 586IPVG, K6-2/+ 450 (Cyrix MII 433), i430VX, 128MB EDO.
BIOS patched by BiosMan (Jan Steunebrink).

cp · Posted: Mon Nov 05, 2007 6:37 pm Post subject:

is the board still running if you remove the jumpers?

KachiWachi · Posted: Tue Nov 06, 2007 12:55 pm Post subject:

Yes...if you mean remove only one set (since something must be connected to the 3.3V source Wink

).

Edit - Clarification.
_________________
CPU - DFI 586IPVG, K6-2/+ 450 (Cyrix MII 433), i430VX, 128MB EDO.
BIOS patched by BiosMan (Jan Steunebrink).