FWIW I finally managed to make a TSR that works for remapping the IRQ, at least well enough that Laser Squad works using the remapped IRQ. However, the performance impact is no longer negligible since it needs to poll the Programmable Interrupt Controllers to sync the IRQ masks, and it doesn't seem to be entirely reliable (probably race conditions with the periodic polling) since I couldn't get It Came from the Desert working. (Laser Squad has configurable IRQ so it was only a test case anyway.)

The source code is on github (https://github.com/arkku/dos_experiments/blob … aster/reirq.asm) in case anyone is interested, but so far the usefulness for me is zero, other than the few experience points gained while making it.

Nice one ! (even if the performance hit is big, it was to be expected IMHO)
Use that talent to patch some drivers 😀

Nice work! Even negative results are often valuable results. You did the experiment, figured out that it has a certain performance penalty and some other problems, so we know this now once and for all. 😀

Arkku wrote:

and it doesn't seem to be entirely reliable (probably race conditions with the periodic polling) since I couldn't get It Came from the Desert working. (Laser Squad has configurable IRQ so it was only a test case anyway.)

You use a timer irq handler on irq 0, I see. I suppose the problem there is that your TSR installs your handler first, but the game may install its own handler after that. This means you rely on the game chaining the IRQs and calling yours after its own handler.
Perhaps It Came From The Desert does not do this.

If you target AT-class machines, they have a second timer on IRQ8, which is rarely used. So you could put the 'IRQ mask watchdog' on the second timer, and it may be more reliable.
Note that this uses an MC146818 chip, so you have to program it differently, and it is less flexible than the 8253 timer on IRQ0. But should be good enough for a watchdog.

I'm really interested in getting one of these great cards. Is it still possible to get one?

I will get a MT-32 and SC-55 in the next few days, so this card would be perfect 😀

I got one maybe a month ago. I absolutely love it. Works in Win 98 and DOS for me.

^ always nice to hear a satisfied user , enjoy and thanks for your support herman43!

@Storm82 , sale info is on serdashop.com but you already find it your self 😀

I was presently surprised when Win 98 recognized it and installed the drivers without me having to do anything. Great piece of kit!

Yes this was expected because the card will work like the Roland MPU-401 so windows just detects it and installs the included driver 😀
There are 2 alternative drivers that work great with the card that allow more than one program to access it - so you don't get the "Device Busy" error, they are included on the software package: http://www.mediafire.com/file/h7qh5c15hz8ft3g … age_v2.zip/file , give them a go if this feature interests you.

Is the midi card still for sale
thanks

madgitty wrote:

Is the midi card still for sale
thanks

Please see this link: https://www.serdashop.com/ISA-MPU-Card it has a link to a contact form you can use.

Just wanted to say: I've just finally installed and tested mine, and it works perfectly. Thanks to everyone involved in creating it!

it is always nice to hear another satisfied user, enjoy the tunes and thanks for your support! 😀

I am happy to present you the next iteration of the PCMIDI card: still the same chipset , the changes are all in the glue logic to the bus so compatibility and performance are not affected:

I will post some real pics once the boards arrive 😀

Volume jumpers and a jack for inserting a MIDI to 3.5mm jack adapter? Nice.

@Keropi: a suggestion I made before that I still think is useful....if the address (300/330) was selectable at the top of the card using a DIP switch would make it much easier to have this exist alongside another card with onboard MIDI like an AWE32. Many games don't allow this to be changed and are hardcoded at 330...so being able to switch this back to 300 so I can init the AWE32 at 330 would be awesome.

@bjwil1991
thanks - btw the volume jumpers were always there

@bjwil1991
I must admit I did not remember this suggestion... but why would one want to have an AWE32 mpu at 330 ? what would be the gain?

Many games are hardcoded to use 330. Suppose I want to load sbk into the awe32 then use midi within the game, it often must be at 330. But in any case having the musicquest and awe32 both at 330 is probably not good. If I can switch the musicquest to 300 before initializing the awe32 at 330 that would be nice. When I want to use the musicquest I set I to 330 and then initialize the awe at 300 or not at all.

yes I know many games are hardcoded to 330 - what I want to know is the advantage of using the AWE32 mpu instead of the PCMIDI one - why would you want that? PCMIDI can do all that a SB mpu can , the "normal" is to move to port300 or disable the SB mpu and use PCMIDI exclusively. The AWE native midi stuff is on port 600something IIRC so you don't lose that

Well the awe32 is a midi synth in it's own right. It is more than a mpu401. The sort of games that are fixed at 330 do not have native AWE support. I do not intend using AWE32 for waveblaster or gameport midi, you are right I would use PCMIDI exclusively for that. So one thing the PCMIDI mpu cannot do is utilize the emu8k on the AWE.