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.
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.
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.
A few pages back, someone with an ASUS board was saying they couldn't get LPC working.
I've done about half the "PCR" file for the LPC device in WPCREDIT on a H55 chipset and it seems to work.
I think these sections may be important. I suspect ISA IRQ routing might be switched off.
It's an ancient tool, (WPCREDIT) but the config file is straightforward enough, and it works in 9x.
1(60:7)=Interrupt Routing Enable PIRQA 0=route to ISA compatible 1=route to 8259PIC 2(60:6)=reserved 3(60:5)=reserved 4(60:4)=reserved 5(60:3)=IRQ 0000,0001,0010,1000,1101 reserved 6(60:2)=IRQ 0011=irq3,0100=irq4,0101=irq5,0110=irq6,0111=irq7 7(60:1)=IRQ 1001=irq9,1010=irq10,1011=irq11,1100=irq12 8(60:0)=IRQ 1110=irq14,1111=irq15 9 10(61:7)=Interrupt Routing Enable PIRQB 0=route to ISA compatible 1=route to 8259PIC 11(61:6)=reserved 12(61:5)=reserved 13(61:4)=reserved 14(61:3)=IRQ 0000,0001,0010,1000,1101 reserved 15(61:2)=IRQ 0011=irq3,0100=irq4,0101=irq5,0110=irq6,0111=irq7 16(61:1)=IRQ 1001=irq9,1010=irq10,1011=irq11,1100=irq12 17(61:0)=IRQ 1110=irq14,1111=irq15 18 19(62:7)=Interrupt Routing Enable PIRQC 0=route to ISA compatible 1=route to 8259PIC 20(62:6)=reserved 21(62:5)=reserved 22(62:4)=reserved 23(62:3)=IRQ 0000,0001,0010,1000,1101 reserved 24(62:2)=IRQ 0011=irq3,0100=irq4,0101=irq5,0110=irq6,0111=irq7 25(62:1)=IRQ 1001=irq9,1010=irq10,1011=irq11,1100=irq12 26(62:0)=IRQ 1110=irq14,1111=irq15 27 28(63:7)=Interrupt Routing Enable PIRQD 0=route to ISA compatible 1=route to 8259PIC 29(63:6)=reserved 30(63:5)=reserved 31(63:4)=reserved 32(63:3)=IRQ 0000,0001,0010,1000,1101 reserved 33(63:2)=IRQ 0011=irq3,0100=irq4,0101=irq5,0110=irq6,0111=irq7 34(63:1)=IRQ 1001=irq9,1010=irq10,1011=irq11,1100=irq12 35(63:0)=IRQ 1110=irq14,1111=irq15 36 37 38 3969:7)=Interrupt Routing Enable PIRQF 0=route to ISA compatible 1=route to 8259PIC 40(69:6)=reserved 41(69:5)=reserved 42(69:4)=reserved 43(69:3)=IRQ 0000,0001,0010,1000,1101 reserved 44(69:2)=IRQ 0011=irq3,0100=irq4,0101=irq5,0110=irq6,0111=irq7 45(69:1)=IRQ 1001=irq9,1010=irq10,1011=irq11,1100=irq12 46(69:0)=IRQ 1110=irq14,1111=irq15 47 48(6A:7)=Interrupt Routing Enable PIRQG 0=route to ISA compatible 1=route to 8259PIC 49(6A:6)=reserved 50(6A:5)=reserved 51(6A:4)=reserved 52(6A:3)=IRQ 0000,0001,0010,1000,1101 reserved 53(6A:2)=IRQ 0011=irq3,0100=irq4,0101=irq5,0110=irq6,0111=irq7 54(6A:1)=IRQ 1001=irq9,1010=irq10,1011=irq11,1100=irq12 55(6A:0)=IRQ 1110=irq14,1111=irq15 56 57(6B:7)=Interrupt Routing Enable PIRQH 0=route to ISA compatible 1=route to 8259PIC 58(6B:6)=reserved 59(6B:5)=reserved 60(6B:4)=reserved
They probably correlate with the later chipsets but if you can be bothered looking through your datasheet, and matching it up, I'm curious to know.
If you haven't figured it out, it decides whether the ISA IRQs get mapped to PCI IRQs A>H and which one is mapped to what.
Call it a route table if you like.
EG Offset 6B reading 0xxx0101 = map from IRQ5 to IRQH (I think) Maybe someone will correct me.
There are remnants of the original file I was editing - some via chipset.
mynewrote on 2026-05-01, 01:05:A few pages back, someone with an ASUS board was saying they couldn't get LPC working. […] Show full quote
A few pages back, someone with an ASUS board was saying they couldn't get LPC working.
I've done about half the "PCR" file for the LPC device in WPCREDIT on a H55 chipset and it seems to work.
I think these sections may be important. I suspect ISA IRQ routing might be switched off.
It's an ancient tool, (WPCREDIT) but the config file is straightforward enough, and it works in 9x.
1(60:7)=Interrupt Routing Enable PIRQA 0=route to ISA compatible 1=route to 8259PIC 2(60:6)=reserved 3(60:5)=reserved 4(60:4)=reserved 5(60:3)=IRQ 0000,0001,0010,1000,1101 reserved 6(60:2)=IRQ 0011=irq3,0100=irq4,0101=irq5,0110=irq6,0111=irq7 7(60:1)=IRQ 1001=irq9,1010=irq10,1011=irq11,1100=irq12 8(60:0)=IRQ 1110=irq14,1111=irq15 9 10(61:7)=Interrupt Routing Enable PIRQB 0=route to ISA compatible 1=route to 8259PIC 11(61:6)=reserved 12(61:5)=reserved 13(61:4)=reserved 14(61:3)=IRQ 0000,0001,0010,1000,1101 reserved 15(61:2)=IRQ 0011=irq3,0100=irq4,0101=irq5,0110=irq6,0111=irq7 16(61:1)=IRQ 1001=irq9,1010=irq10,1011=irq11,1100=irq12 17(61:0)=IRQ 1110=irq14,1111=irq15 18 19(62:7)=Interrupt Routing Enable PIRQC 0=route to ISA compatible 1=route to 8259PIC 20(62:6)=reserved 21(62:5)=reserved 22(62:4)=reserved 23(62:3)=IRQ 0000,0001,0010,1000,1101 reserved 24(62:2)=IRQ 0011=irq3,0100=irq4,0101=irq5,0110=irq6,0111=irq7 25(62:1)=IRQ 1001=irq9,1010=irq10,1011=irq11,1100=irq12 26(62:0)=IRQ 1110=irq14,1111=irq15 27 28(63:7)=Interrupt Routing Enable PIRQD 0=route to ISA compatible 1=route to 8259PIC 29(63:6)=reserved 30(63:5)=reserved 31(63:4)=reserved 32(63:3)=IRQ 0000,0001,0010,1000,1101 reserved 33(63:2)=IRQ 0011=irq3,0100=irq4,0101=irq5,0110=irq6,0111=irq7 34(63:1)=IRQ 1001=irq9,1010=irq10,1011=irq11,1100=irq12 35(63:0)=IRQ 1110=irq14,1111=irq15 36 37 38 3969:7)=Interrupt Routing Enable PIRQF 0=route to ISA compatible 1=route to 8259PIC 40(69:6)=reserved 41(69:5)=reserved 42(69:4)=reserved 43(69:3)=IRQ 0000,0001,0010,1000,1101 reserved 44(69:2)=IRQ 0011=irq3,0100=irq4,0101=irq5,0110=irq6,0111=irq7 45(69:1)=IRQ 1001=irq9,1010=irq10,1011=irq11,1100=irq12 46(69:0)=IRQ 1110=irq14,1111=irq15 47 48(6A:7)=Interrupt Routing Enable PIRQG 0=route to ISA compatible 1=route to 8259PIC 49(6A:6)=reserved 50(6A:5)=reserved 51(6A:4)=reserved 52(6A:3)=IRQ 0000,0001,0010,1000,1101 reserved 53(6A:2)=IRQ 0011=irq3,0100=irq4,0101=irq5,0110=irq6,0111=irq7 54(6A:1)=IRQ 1001=irq9,1010=irq10,1011=irq11,1100=irq12 55(6A:0)=IRQ 1110=irq14,1111=irq15 56 57(6B:7)=Interrupt Routing Enable PIRQH 0=route to ISA compatible 1=route to 8259PIC 58(6B:6)=reserved 59(6B:5)=reserved 60(6B:4)=reserved
They probably correlate with the later chipsets but if you can be bothered looking through your datasheet, and matching it up, I'm curious to know.
If you haven't figured it out, it decides whether the ISA IRQs get mapped to PCI IRQs A>H and which one is mapped to what.
Call it a route table if you like.
EG Offset 6B reading 0xxx0101 = map from IRQ5 to IRQH (I think) Maybe someone will correct me.
There are remnants of the original file I was editing - some via chipset.
I'm aware of these IRQ routing registers (60h and 68h). AFAIK these seems to be read only once you're already in an OS (including DOS). Don't know if it's possible to reimplement "PnP/PCI configuration" menu in modern UEFI so these registers can be fiddled somewhat.
For me, these registers can serve as a hint to note which PIRQ line is active and which IRQ has been taken. So take note of which register is reading 05h or 07h and see if you can disable enough onboard devices to turn off certain PIRQ lines (the byte will then read 80h) or make it use a different IRQ.
PS: IIRC if you're in an APIC-enabled operating system PIRQ lines will go to APIC (you'll see the PCI hardware taking IRQs 16 and above from Device Manager), so these registers become less relevant in that scope.
I managed to change them and totally crash the win98 H55 AMIBIOS8 I was testing it on.
YMMV.
Try wpcredit if you're bored. When I get time, I should finish it. It just takes a while.
Did you manage to actually change its content while in Windows (via WPCREDIT)?
IIRC when I fiddled those registers myself while in DOS the values appear unchanged when I read them again. From what I read in the documentations these values need to be set while in BIOS.
It seems there's another tool that can parse files made by WPCREDIT.
As for WPCREDIT, I don't think it's of any good use for initializing the dISAppointment, as the OS won't be able to load the driver for the ISA sound card behind it, until WPCREDIT has been run, which would be quite late. It may be useful for altering the behavior of certain hardware that can already be detected by the system, though.
A few pages back, someone with an ASUS board was saying they couldn't get LPC working.
There are a few issues with ASUS that I'm already aware, but I'm not sure about others.
- LDRQ1# is being configured as GPIO23. My "lpcisa" tool can automatically correct this during configuration.
- ISA PnP (namely port A79h) is not accessible preventing use of ISA PnP cards. This is not ASUS-specific, AFAIK only ASRock boards have working ISA PnP.
- Some higher-end boards come with TPU chips which also reside on the LPC bus. Not sure if they will affect actual functionality of the bridge IC but so far their presence appear to interfere with configuration ports (4Eh/4Fh).
None of these issues are directly related to PIRQ assignments... however...
MSI's Z87M Gaming, Gigabyte's Z87M-D3H/B85m-D3H - all good with ISA PnP (read: UNISOUND works)
BTW they have both PS/2 lines mouse+kb at the connector, proper Y-cable required, not the one sold on Ali (but fixable).
MSI's Z87M Gaming, Gigabyte's Z87M-D3H/B85m-D3H - all good with ISA PnP (read: UNISOUND works)
BTW they have both PS/2 lines mouse+kb at the connector, proper Y-cable required, not the one sold on Ali (but fixable).
Thanks for the report. I don't have boards of these vendors at the moment, so I'm not sure.
Do PS/2 Y-cables work out-of-box on these boards? I don't remember seeing other vendors than ASRock offering the BIOS option for Y-cables.
I managed to change them and totally crash the win98 H55 AMIBIOS8 I was testing it on.
YMMV.
Try wpcredit if you're bored. When I get time, I should finish it. It just takes a while.
Did you manage to actually change its content while in Windows (via WPCREDIT)?
IIRC when I fiddled those registers myself while in DOS the values appear unchanged when I read them again. From what I read in the documentations these values need to be set while in BIOS.
It seems there's another tool that can parse files made by WPCREDIT.
As for WPCREDIT, I don't think it's of any good use for initializing the dISAppointment, as the OS won't be able to load the driver for the ISA sound card behind it, until WPCREDIT has been run, which would be quite late. It may be useful for altering the behavior of certain hardware that can already be detected by the system, though.
A few pages back, someone with an ASUS board was saying they couldn't get LPC working.
There are a few issues with ASUS that I'm already aware, but I'm not sure about others.
- LDRQ1# is being configured as GPIO23. My "lpcisa" tool can automatically correct this during configuration.
- ISA PnP (namely port A79h) is not accessible preventing use of ISA PnP cards. This is not ASUS-specific, AFAIK only ASRock boards have working ISA PnP.
- Some higher-end boards come with TPU chips which also reside on the LPC bus. Not sure if they will affect actual functionality of the bridge IC but so far their presence appear to interfere with configuration ports (4Eh/4Fh).
None of these issues are directly related to PIRQ assignments... however...
I'd be curious to see a register dump of a working, vs nonworking on the same chipset.
I have some theories...
MSI's Z87M Gaming, Gigabyte's Z87M-D3H/B85m-D3H - all good with ISA PnP (read: UNISOUND works)
BTW they have both PS/2 lines mouse+kb at the connector, proper Y-cable required, not the one sold on Ali (but fixable).
Thanks for the report. I don't have boards of these vendors at the moment, so I'm not sure.
Do PS/2 Y-cables work out-of-box on these boards? I don't remember seeing other vendors than ASRock offering the BIOS option for Y-cables.
I have all of those boards on hands (they're time to time appeared on local flea markets for 30-50USD) with LDRQ1 connected to the TPM header. With modded ES1898F (recap, important for output stage, must have) - joy machine.
PS/2 Y-splitter from Ali requires rewiring. According to boards schematics Asrock, Gigabyte and MSI Z87M/B85M with dual-colored PS/2 has both lines (mouse/kb) correctly wired down to the Multi/IO chip, both clock and data separately.
"Default" PS/2 Y-cables are just plain splitters 1:1 mirrored, while proper splitter requires rewiring clock and data for both kb and mouse being rewired to the correct pins of PS/2 on the devices end.
Also there's still PS/2 mices sold "new" from HP/Dell OEM'ed by Primax, paracord mod with thin wires = modern PS/2 gaming optical mice. MSI Z87M Gaming has flawed USB->PS/2 mice emulation with both non reacting on LMB (you click = nothing happened) and overreacting (several LMB sent instead of one physical), but with PS/2 - flawless and far less input lag.
Some report on my ASRock H97M-Pro4, tested with the HKZLab's ES1868/1869 card I've assembled.
- ISA PnP works. UNISOUND correctly initialized the card using /XEA option.
- With IRQ5 everything works out-of-box, even with a Montego II (AU8830) and an Audigy 2 ZS installed on PCI slots, and with onboard COM and LPT ports enabled in default config.
- Sound, FM and MIDI all work without issues. This card apparently works better on Wolf3D engine games than my CT2950 from what I tested.
- PS/2 Y-Cable supported on this board, and works without issues.
LDRQ1# location in the screenshot. Note that you need to remove the heatsink to access it, just like X99M Killer/3.1.
Z97M-Pro4 has the same layout and LDRQ1# is also in the same place there, so Z97M-Pro4 should in theory behave the same as the H97M-Pro4.
TIP: The two middle pins in the SPEAKER1 are NC so it's perfectly safe to wire LDRQ1# to one of those two pins for convenience.
LSS10999wrote on Today, 03:22:Some report on my ASRock H97M-Pro4, tested with the HKZLab's ES1868/1869 card I've assembled. […] Show full quote
Some report on my ASRock H97M-Pro4, tested with the HKZLab's ES1868/1869 card I've assembled.
- ISA PnP works. UNISOUND correctly initialized the card using /XEA option.
- With IRQ5 everything works out-of-box, even with a Montego II (AU8830) and an Audigy 2 ZS installed on PCI slots, and with onboard COM and LPT ports enabled in default config.
- Sound, FM and MIDI all work without issues. This card apparently works better on Wolf3D engine games than my CT2950 from what I tested.
- PS/2 Y-Cable supported on this board, and works without issues.
LDRQ1# location in the screenshot. Note that you need to remove the heatsink to access it, just like X99M Killer/3.1.
Z97M-Pro4 has the same layout and LDRQ1# is also in the same place there, so Z97M-Pro4 should in theory behave the same as the H97M-Pro4.
TIP: The two middle pins in the SPEAKER1 are NC so it's perfectly safe to wire LDRQ1# to one of those two pins for convenience.
Cool. Have you managed to run Windows 98 on this mobo (considering Montego and A3D) ? I have no luck with any PCIe graphics card on Asrock's Z87M/B85M Pro4s - both Nvidia and Ati, only PCI graphics cards. Something about resource conflict. Is PS/2 mouse wild or okay in 98 ?
LSS10999wrote on Today, 03:22:Some report on my ASRock H97M-Pro4, tested with the HKZLab's ES1868/1869 card I've assembled. […] Show full quote
Some report on my ASRock H97M-Pro4, tested with the HKZLab's ES1868/1869 card I've assembled.
- ISA PnP works. UNISOUND correctly initialized the card using /XEA option.
- With IRQ5 everything works out-of-box, even with a Montego II (AU8830) and an Audigy 2 ZS installed on PCI slots, and with onboard COM and LPT ports enabled in default config.
- Sound, FM and MIDI all work without issues. This card apparently works better on Wolf3D engine games than my CT2950 from what I tested.
- PS/2 Y-Cable supported on this board, and works without issues.
LDRQ1# location in the screenshot. Note that you need to remove the heatsink to access it, just like X99M Killer/3.1.
Z97M-Pro4 has the same layout and LDRQ1# is also in the same place there, so Z97M-Pro4 should in theory behave the same as the H97M-Pro4.
TIP: The two middle pins in the SPEAKER1 are NC so it's perfectly safe to wire LDRQ1# to one of those two pins for convenience.
Cool. Have you managed to run Windows 98 on this mobo (considering Montego and A3D) ? I have no luck with any PCIe graphics card on Asrock's Z87M/B85M Pro4s - both Nvidia and Ati, only PCI graphics cards. Something about resource conflict. Is PS/2 mouse wild or okay in 98 ?
I did succeed in installing Win98SE using QuickInstall, using reference images.
I used the "Win98SE 98Lite Micro" option, and SATA is configured in AHCI mode.
Apparently these 98Lite debloated options by default have ACPI disabled, and in my experience with newer boards, ACPI was known for causing quite a few quirks in from resource conflicts to hardware being totally absent from Device Manager.
Everything works with mostly default configurations plus a few additional stuffs like CREGFIX and LBA64 (not necessarily required). Just a few caveats:
- On the initial boot right after install I ended up in a blank screen with blinking text cursor. Keyboard works but I cannot reboot for some reasons. After restart it checked for errors and the rest of the preparation process finished without issues.
- Since I did not let it detect legacy non-PnP hardware during install phase, by default Windows configured two COM ports in the hardware profile, while the board has only one. The additional COM2 will not report error but it prevented onboard devices that's using IRQ3 from working. In my case that would be the AHCI controller and the PCI bridge responsible for the PCI slots with my sound cards. The COM2 port needs to be removed for IRQ3 to be usable, and Windows will automatically remove it when detecting non-PnP hardware using "Add New Hardware" wizard.
- From REGEDIT I noticed some garbled stuffs in the registry but so far they have not caused issues to the system.
- NVMe driver doesn't work on my system citing being unable to share IRQ. Since I'm not using the SSD (plugged into the PCIe x4 slot via adapter) for Win9x I just disabled it.
Both PS/2 keyboard and mouse (behind a Y-cable) work fine in Win98.
I only installed drivers for Montego II which is already included in the QuickInstall's extra driver pack. It works, just I got a notice about the card not being on the primary PCI bus, which is not really an issue (as it simply disables SB emulation support).
I did not install drivers for my Audigy 2 ZS as I don't intend to use that card there, and the driver pack doesn't appear to have it, though its 1394 controller can be driven using standard 1394 drivers...
As for video, I think VBESVGA, VBEMP and even SoftGPU's VESA driver will work fine after proper configuration. I'm using a single-slot FirePro W7000 with SoftGPU driver. Performance is slower than VBEMP but it kind of allows at least D3D7 to work. Note that on AMD video cards "NoMemTest" must be set to 1 in the VESA driver as memory test doesn't work correctly (more details in SoftGPU thread).
As for video, I think VBESVGA, VBEMP and even SoftGPU's VESA driver will work fine after proper configuration. I'm using a single-slot FirePro W7000 with SoftGPU driver. Performance is slower than VBEMP but it kind of allows at least D3D7 to work. Note that on AMD video cards "NoMemTest" must be set to 1 in the VESA driver as memory test doesn't work correctly (more details in SoftGPU thread).
Nvidia 6800,7900GS in form of Quadro still ~25$ on eBay, I'm more interested in native drivers, which (both Nvidia and ATI) has resource conflict somewhere in very low ports range, not IRQ. This conflicts looks absolutely absurd BTW. port 79 or something.
Gigabyte's Z87M/B85M -D3Hs (same PCB essentially) - no issues: correctly installed and working. The same for Asus Z87 Gryphon OORC. Wild USB->ps/2 mouse emulation though.