it’s my own project which incorporates both bridge and sound chips on a single pcb. this special header on the mobo inspired me trying it. yes master# signal is pulled up to 5v line via 4.7k resistor.

6300esb datasheet has e2h register related to legacy sound cards io, but it’s stated as not validated whatever it means. i decided to give a try but stuck at the very beginning.

anthony wrote on 2026-02-14, 22:18:

it’s my own project which incorporates both bridge and sound chips on a single pcb. this special header on the mobo inspired me trying it. yes master# signal is pulled up to 5v line via 4.7k resistor.

6300esb datasheet has e2h register related to legacy sound cards io, but it’s stated as not validated whatever it means. i decided to give a try but stuck at the very beginning.

Hmmm... looks like older ICHs have only two generic decode ranges (E4h and ECh) for LPC, compared to later ones which has four. This kind of matches the functionality of the Winbond LPC-ISA bridge, W83626.

The register E2H you mentioned is no longer present on ICH5 datasheet. Bits related to sound cards in E6H are also marked as "Reserved" there. I don't think they're that relevant, however, as at least with MIDI and SB decode ranges they are too few for some modern sound cards, including GUS.

I think you'll have to look for earlier boards (late PIII or early P4) with ISA slots that incorporated LPC-ISA instead of PCI-ISA, to see whether these decode range registers had any use back then.

Alright, what is the differecne between 0.3 and 0.4 revisions of this bridge board?

anthony wrote on 2026-02-16, 02:24:

Alright, what is the differecne between 0.3 and 0.4 revisions of this bridge board?

IIRC just some silkscreen cleanups.

It's just that LSS10999 had trouble getting 0.3 to work, but IIRC also had some dodgy bridge chips so it might just have been that

One more mobo tested: MSI Z87M Gaming, LDRQ1 exposed/available/working.
Quite serious VRM, Z87 Gryphon class.
Mobo has no VGA/DVI ports, all of the graphics ports - digital (DP/HDMI).
No issues with ISA PnP ports ranges availability.
Terrible USB mices support in DOS: LMB has both issues: not clicking and excessive over clicking (1 physical click registered as several clicks).
Lot of cheap/expensive mices tested, seems polling rate related, because very basic mices has less issues (just not registering sometimes LMB clicks: you click = nothing happens)
KB/Mouse while plugged both in USB ports jam each other in DOS badly as well: the same issues like with mouse, but now with keyboard keys: not registering or overregistering key down.
One should use PS/2 mouse only - hours without issues (combined port, only one device allowed). Actually boardview clearly shows all the lines connected (both KB/MS data/clock to the PS/2 header), Y-cables of mine are 1:1 to both legs, after rewiring I'll report back. The same wiring in Gigabyte's Z87M/B85M D3H and I suppose Asrock's Z87M/B85M as well.
External graphics card + PS/2 mouse - success.
Overall ? Recommended. LDRQ1 pin location attached.

I just tested a v0.4 board I assembled a few weeks ago. Looks like it's really working. I wonder what might be the real reason behind the troubles I had with v0.3 assemblies.

Haven't tested it in-depth. I powered it on with an ISA POST card over my B450M testbed and I could see outputs on the card, as well as being able to show arbitrary values I wrote to port 80h. This is all I could achieve on AMD hardware at the moment.