I was using for years a MPU-401AT in my 233mmx DOS system. I did not notice any issues until I tried to play Gateway: mpu interface not detected 😲
It was about the same time that Phil was messing with PCI sata cards and had issues - he made the connection with ACPI and solved it by disabling it.
I did the same and Gateway worked. Over the last couple of years I gave the same advice to people that could not get PCMIDI working 100% in their ss7 system, it was always ACPI and people forgetting to disable/move their main soundcard's mpu.
That's my experience so far with this 😊

I wonder.
Would there be a way to combine the abilities of the HardMPU card with the ability of SoftMPU to pause the execution of the game with SysEx delayed messages.
That is to say, a simple TSR that would not require a memory manager that would only poll or check a status on the HardMPU card, and if/when necessary, pause the CPU in the same way SoftMPU does natively.

The ISA device can extend IO cycles to as long as necessary by means of the IORDY pin (though on pre 386 systems there may be issues with memory refresh then, same as with bus mastering devices)

If this sounds crazy, let me know. How about HardMPU as a PCMCIA card for laptops? The SCP-55 is hard to find these days and sometimes, the MIDI/Joystick port on the port replicators are a bit touchy at times.

tpowell.ca wrote:

I wonder.
Would there be a way to combine the abilities of the HardMPU card with the ability of SoftMPU to pause the execution of the game with SysEx delayed messages.
That is to say, a simple TSR that would not require a memory manager that would only poll or check a status on the HardMPU card, and if/when necessary, pause the CPU in the same way SoftMPU does natively.

HardMPU already does SysEx delay, and it doesn't require pausing execution of the game*. It can be enabled using the config utility from the HardMPU Github page.

Edit: *with any games I've tried so far, I should say. X-Wing is a good example... With SoftMPU the delay caused stuttering of the graphics, but it is nice and smooth with HardMPU, yet doesn't crash the MT32.

bjwil1991 wrote:

If this sounds crazy, let me know. How about HardMPU as a PCMCIA card for laptops? The SCP-55 is hard to find these days and sometimes, the MIDI/Joystick port on the port replicators are a bit touchy at times.

I'll have to look a little more into the standard. PCMCIA is "based on" ISA, but doesn't seem to have all the same signals. The bigger issue is what would one use for an enclosure?

Didn't think of that. Some port replicators/docking stations had an ISA slot or two, as well as PCI slots in later versions for installing sound cards, MIDI cards, 3dfx or better video cards, and so on.

ab0tj wrote:

HardMPU already does SysEx delay, and it doesn't require pausing execution of the game*. It can be enabled using the config utility from the HardMPU Github page.

Edit: *with any games I've tried so far, I should say. X-Wing is a good example... With SoftMPU the delay caused stuttering of the graphics, but it is nice and smooth with HardMPU, yet doesn't crash the MT32.

I was thinking more in line with 2 options, and forgive me as I don't know exactly how the HardMPU implementation works exactly, so I may make an ass out of myself here.
1. Make the utility/TSR such that if a game finishes sending SysEx commands and starts to play music but the HardMPU is still busy sending the SysEx buffer, to call on the TSR to pause the game.
2. Make the utility/TSR such that if the ring buffer in the HardMPU processors gets to a specific fill threshold, to call on the TSR to pause the game (for debugging as this would most likely cause animation stutter).

Does this make sense?

What you're saying makes sense but I guess I'm not entirely clear on the use case yet. I'm not saying you're wrong, sometimes I'm just a bit dense. 😎
What you're describing sounds just like using SoftMPU but with HardMPU as the physical interface.

ab0tj wrote:

What you're saying makes sense but I guess I'm not entirely clear on the use case yet. I'm not saying you're wrong, sometimes I'm just a bit dense. 😎
What you're describing sounds just like using SoftMPU but with HardMPU as the physical interface.

Actually come to think of it, you're right. Loading SoftMPU with HardMPU would match my point #1. I guess I was hoping for a version of the utility that could still leverage the HardMPU hardware in intelligent mode.

The use case being games that don't work quite right and finding out if speed is truly the issue I suppose. For example my broken Wing Commander II game, which works fine on SoftMPU but plays the wrong effects with HardMPU, regardless of delayed SysEx.

tpowell.ca wrote:

Actually come to think of it, you're right. Loading SoftMPU with HardMPU would match my point #1. I guess I was hoping for a version of the utility that could still leverage the HardMPU hardware in intelligent mode.

The use case being games that don't work quite right and finding out if speed is truly the issue I suppose. For example my broken Wing Commander II game, which works fine on SoftMPU but plays the wrong effects with HardMPU, regardless of delayed SysEx.

Gotcha. I will try Wing Commander II when I get a chance, my main DOS gaming rig is a K6-III+ so it usually makes speed issues pretty apparent.

I finally got a chance to test WC II on my machine at home. I don't seem to have the same issue as you, so I'm thinking an IRQ conflict might be likely. I'll spend some more time playing with different speeds and BIOS settings over the next few days to see if I can replicate the issue.
I'm curious, if you change the IRQ jumper on your HardMPU board to something other than 2, does it break WC II entirely?

I will admit that the default IRQ 2/9 is shared by ACPI on my motherboard which cannot be disabled or moved but even when I set the card to IRQ 3, the problem persisted.

I'm wondering if maybe my card is defective 🙁

tpowell.ca wrote:

I'm wondering if maybe my card is defective 🙁

Unfortunately I doubt it's that simple. The way the interface works, the issue would most likely affect more than just the one game if that were the case.
I'm going to do some more testing, maybe it is a speed issue and I just haven't found the right combination of settings to bring it out yet.

I should add, without slowing my machine down, WCII does run far too fast. But, sound effects are still correct without speed adjustment 😕

I just can't figure it out.
I tried on my 486DX4-133 computer with turbo off and while the game is slightly too fast, the MT32-specific music and sound effects are again, completely wrong, in fact, its worse. On this machine, the intro visuals are ahead of the music and only catch up at the end during the fireworks.
This is a different computer, different MPU-401 card, different MT-32 synth.

I thought maybe my game is corrupted, but after doing a CRC check with a copy I got from GOG, my files all match. And again, on the 486, loading softMPU solves the problem (with and without the sysex delay).

Sorry if you already answered this but I haven't seen... Have you moved the MIDI functionality of any other sound cards in the system away from port 330?

ab0tj wrote:

Sorry if you already answered this but I haven't seen... Have you moved the MIDI functionality of any other sound cards in the system away from port 330?

Definitely. I have 2 other soundcards, none of which have an MPU port enabled.

I also tried taking out my 2 cards leaving only the HardMPU card, but it had no effect on the problem.

(moved this conversation to PMs)

ab0tj wrote:

chrishenkel wrote:

I am interested in a HardMPU PCB.

Please let me know if any are available.

PM sent

Greetings,

I'll be interested in acquiring a PCB or two. Please let me know if there are some to acquire or a lead time.