Well, when this is 100% confirmed, I will add it to my list here 😁
Identifying PCChips 386 era chipsets

Woah! MR-BIOS? 😮
I should soon get some eeproms that i've ordered some time ago. Definitely will try out that bios, too! (Y)

Madowax wrote on 2020-09-30, 15:03:

Old thread resurrection but PC Chips m321 should be based on 82c391/82c392/82c206 Opti-386WB Chipset, here is the datasheet for future reference. The Bus divider options are clk2in/8 or clk2in/6, so with an am386dx40 (80 Mhz crystal) and the 8 divider the actual isa bus is 10Mhz. Input PIN 14 (BCLKS) of 82c391 selects the multiplier, if low clk2in/8 is selected, if high clk2in/6 is used.
IC marked CHIP 5 is the 82c392 while IC marked CHIP 6 is the 82c391.

Sadly, as far as i am able to understand this, this doc doesn't seem to match with my motherboard's register values.
I used AMISETUP and checked bits in registers 20h, 21h, 22h, 25h and couldn't match anything with the docs. Had completely non-sensical bits in those registers according to this datasheet.
I also checked registers from AMISETUP's "Extended/Chipset Setup", which shows register, bits in it and what those bits do, and it also doesn't seem to match the datasheet. (I made a picture from AMISETUP, that shows some common registers, bitmasks and current settings with description for comparission)

For MR.BIOS, i still need to get the proper EEPROMS before i can try it out. I'll definitely let you know, when that happens. 😀

GigAHerZ wrote on 2020-10-03, 09:49:

Sadly, as far as i am able to understand this, this doc doesn't seem to match with my motherboard's register values. I used AMIS […]
Show full quote

Madowax wrote on 2020-09-30, 15:03:

Old thread resurrection but PC Chips m321 should be based on 82c391/82c392/82c206 Opti-386WB Chipset, here is the datasheet for future reference. The Bus divider options are clk2in/8 or clk2in/6, so with an am386dx40 (80 Mhz crystal) and the 8 divider the actual isa bus is 10Mhz. Input PIN 14 (BCLKS) of 82c391 selects the multiplier, if low clk2in/8 is selected, if high clk2in/6 is used.
IC marked CHIP 5 is the 82c392 while IC marked CHIP 6 is the 82c391.

Sadly, as far as i am able to understand this, this doc doesn't seem to match with my motherboard's register values.
I used AMISETUP and checked bits in registers 20h, 21h, 22h, 25h and couldn't match anything with the docs. Had completely non-sensical bits in those registers according to this datasheet.
I also checked registers from AMISETUP's "Extended/Chipset Setup", which shows register, bits in it and what those bits do, and it also doesn't seem to match the datasheet. (I made a picture from AMISETUP, that shows some common registers, bitmasks and current settings with description for comparission)

For MR.BIOS, i still need to get the proper EEPROMS before i can try it out. I'll definitely let you know, when that happens. 😀

If I'm not mistaken those in amisetup are CMOS registers not chipset registers. It's normal they don't match.

From AMISETUP.DOC
"Register
Hexadecimal number of the CMOS register that stores the setting. This information may help experienced users to change settings manually using Change Register. If a `+' sign is displayed after the register number, there might be other registers affected."

Basically it's the place in CMOS memory mapping where Ami Hi-flex bios stores that setting.
Take a look here:
http://bochs.sourceforge.net/techspec/CMOS-reference.txt

Oh, so at least with the help of AMISETUP, there's nothing really to match for me to confirm the chipset?

GigAHerZ wrote on 2020-10-04, 13:40:

Oh, so at least with the help of AMISETUP, there's nothing really to match for me to confirm the chipset?

Maybe under diagnostic menu there is something which can give away the chipset the mobo is using.

Madowax wrote on 2020-10-06, 05:34:

GigAHerZ wrote on 2020-10-04, 13:40:

Oh, so at least with the help of AMISETUP, there's nothing really to match for me to confirm the chipset?

Maybe under diagnostic menu there is something which can give away the chipset the mobo is using.

Bios Version:

1BIOS source: Protected Mode
2BIOS manufacturer: American Megatrends, INC.
3BIOS revision: HighFlex (A)
4BIOS date: 06/06/92
5BIOS version seems to be OK

CMOS RAM checksums:

1CMOS RAM size: 128 Bytes
2First checksum: OK (10-2D: 048B)
3Second checksum: OK (34-6B: 057C)
4CMOS RAM checksums seem to be OK

Doesn't click anything for me... 🙁

Woah! Computer booted up with V020B324 bios!

Detects processor, memory, cache amounts all correctly.

So i think we can now conclude, this is a 82C391 chipset based board? Amazing!

What are those T-, T+, CL- and CL+ variants about?
It also complains that it does not detect the keyboard, so i can't enter the bios from boot. Yet, the keyboard does work in DOS and with ctrl + alt + esc, i can enter bios and keyboard works inside bios config as well. That's weird...

EDIT: Found the answer for T-, T+, etc:
-----------------------------------------------------------------
8042 Turbo/Turbo-LED control: (T-) (T+) (TL-) (TL+) (CL-) (CL+)
-----------------------------------------------------------------

Hot-Key TURBO and/or LED control via keystrokes <CTRL> <ALT> <-/+> will
simultaneously activate all commonly used 8042 pins: 23,24, 27,28,29,30.

The system board layout must connect one of these pins to an existing
Turbo/LED circuit. Consideration should be given to the remaining pins
which are also driven. MR BIOS (r) 8042 or AMI KF keyboard controller
may be used for this purpose. Award, Phoenix, and Quadtel 8042's cannot
be used with any MR BIOS (r) version designated as having this special
8042 functionality.

Active
Legend Function State Description
------ -------- ----- --------------------------------------------
(T-) Turbo Low 8042 turbo/LED circuit ONLY (no chipset register
(T+) Turbo High turbo). Also, Setup Utility SPEED screen appears.

(TL-) Turbo-LED Low Both chipset turbo and 8042 pins are activated.
(TL+) Turbo-LED High

(CL-) Cache-LED Low Used mainly with 486, Cache state indicates "turbo".
(CL+) Cache-LED High

You mean UMC UM82C491* ^^

Now maybe the keyboard issue is an indication that it's not the right chipset ? I don't know ... Even if that's a really good indication, I think we'll have to find something unique to this UMC chipset to be 100% sure that it's not a lucky shot.

Maybe this could help ? UMC UM82C491 datasheet?

Anyways, this is a major step ! 😀

Madowax wrote on 2020-10-02, 04:56:

If you hex edit a m321 rev.2.7 bios dump you will find references to 82c391/82c391b, regarding the ISA Bus dividers: "This is v […]
Show full quote

Deksor wrote on 2020-10-01, 05:58:

How do you know ? Can you test the m321 with a bios for that chipset just to make sure ? ^^

If you hex edit a m321 rev.2.7 bios dump you will find references to 82c391/82c391b, regarding the ISA Bus dividers: "This is valid only for 82C391B Chipset. The options are: -Jumper : AT Bus Clock is CPU clock input divided either by 6 or by 8 determined by hardware jumper. CLKIN/10 : AT Bus Clock is CPU clock input divided by 10. For 82C391 Chipset, this is "Reserved"." take a look, in my dump this is at OFFSET BC3F . The layout also fits and from a pictures analysis also the chipset connections. As I said it should be based on that chipset. I could be mistaken ofc. Sadly I don't have the mobo, so someone else should test the bios on his board. There is a Mr.Bios for it, I will post it here.

-------------------------------------------------
OPTi WriteBack 82C391 / 82C491 / 82C493 / 82C495
-------------------------------------------------

NOTICE: 386: Beginning Ver 1.40, Dirty-Bits are optional, all cache sizes.
493/5: Beginning Ver 1.41, Dirty-Bits are required only with 512K
cache. 64K, 128K, 256K may omit Dirty-Bits.


Filename Port Description (386-WB Revs A,B)
-------- ------- ---------------------------------------------------------
V020B324 OPTI324 82C391 - 386 WriteBack Revs A,B
V020B32B OPTI32B x020B324 with C&T 82C711 multi-IO
V020B32C OPTI32C x020B324 with NSC PC87310 Super-IO

V020B32E OPTI32E x020B324 (T-)
V020B32F OPTI32F x020B324 (T+)
V020B32G OPTI32G x020B324 (CL-)
V020B32H OPTI32H x020B324 (CL+)

V020B32J OPTI32J x020B32B (711) (T-)
V020B32K OPTI32K x020B32B (711) (T+)
V020B32L OPTI32L x020B32B (711) (CL-)
V020B32M OPTI32M x020B32B (711) (CL+)

V020B32P OPTI32P x020B32C (310) (T-)
V020B32Q OPTI32Q x020B32C (310) (T+)
V020B32R OPTI32R x020B32C (310) (CL-)
V020B32S OPTI32S x020B32C (310) (CL+)

Based on this, it should be Opti 82C391 and the bios says "OPTi 82C391-A".

MR BIOS documents all over the internet sometimes mention MR BIOS' own keyboard controller or AMIKEY keyboard controller to be compatible, and others not. I have some unknown HT6242 chip on my board...

EDIT:
Found this website: http://chukaev.ru54.com/bios_cs_en.htm
Searched for 82C391 and tried out those bioses.
The ones that did work for my board: 3opm001, 3opm011
Didn't work: 3opm005, 3opm012

So i can additionally confirm that this is the chipset on that popular M321 PC Chips board!

EDIT2:
MR Bios 1.30 also works from this thread: Best 386 Motherboard?

Opti 82C391 you say ?

Would you like to try this ? http://www.win3x.org/win3board/viewtopic.php?t=26070

It has specific support for the Opti 82C391 (among the other listed chipsets) and if it works as intended, that'll definitely confirm that this board's chipset is opti 😀 (plus it's a pretty cool piece of software allowing you to allocate UMBs without EMM386 and lets you load HIMEM.SYS high, among other neat things).

I have added it to my "identified chipsets" list ^^

Deksor wrote on 2020-12-21, 21:19:

Opti 82C391 you say ? […]
Show full quote

Opti 82C391 you say ?

Would you like to try this ? http://www.win3x.org/win3board/viewtopic.php?t=26070

It has specific support for the Opti 82C391 (among the other listed chipsets) and if it works as intended, that'll definitely confirm that this board's chipset is opti 😀 (plus it's a pretty cool piece of software allowing you to allocate UMBs without EMM386 and lets you load HIMEM.SYS high, among other neat things).

I have added it to my "identified chipsets" list ^^

Tried it, but unless i do something wrong, then /C=09, which should be for that chipset, gives me an error, that chipset is unrecognized... 🙁

I'm successfully using EMM386 or QEMM97 or JemmEx or RDOSUMB (without specifying the chipset) for UMB.

I also found a bios for HOT-307H board ( https://arvutimuuseum.ee/th99/m/S-T/31004.htm ) and tried it and it also boots!
So i'm getting pretty confident that this is a 82C391 based board. (Y)

Confirmed!
I changed original keyboard controller (HT6542) to a AMIKEY-2 keyboard controller with datecode from year 1996 and i don't get any keyboard errors any more!
100% working now!

There is also a Dataexpert AMIBIOS here: http://www.win3x.org/uh19/motherboard/show/1481 (if you'd like to test another one).

I already have leads to a possible SARC4018 (CHIP 11) -> UMC 82C491, so this result wouldn't surprise me.

GigAHerZ wrote on 2020-12-28, 18:08:

Confirmed!
I changed original keyboard controller (HT6542) to a AMIKEY-2 keyboard controller with datecode from year 1996 and i don't get any keyboard errors any more!
100% working now!

That is due to the fact that not every KBC revision or model has the same gpio pins behavior, gpio pins of KBCs were used for different purposes by different manufacturers and different bioses. Like the Turbo enable/disable function common in AMI or Mr.Bios or the GATEA20 line, those were achieved using one of the GPIO pins of the KBC. So newer bios or general chipset bios might work with some KBCs and not
with others or they can give you strange errors or behavior even if they are almost working.

Alejandro Lieber wrote on 2019-04-17, 13:00:

The M-321 Mainboard User's Guide gives no instructions on how to change the divider.

Any chance I could get a copy of the M-321 80386 Mainboard User's Guide? 😀