digger wrote on 2026-09-07, 17:20:

Hi @FreddyV. Got it. IRQ3 only. […]
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FreddyV wrote on 2026-09-07, 16:09:

Hi @digger

For tandy 1000 EX, you should keep only the IRQ3 wired. Only 2,3,4

Picomem 2 multiplexed irq is still only on IRQ7

Hi @FreddyV. Got it. IRQ3 only.

What exactly do you mean with "Only 2,3,4"? Those can't be IRQs. Do you mean "remove jumpers 2, 3 and 4", since I should only have jumper 1 in place for IRQ 3?

I'm going to try it tonight and share my findings here.

Thanks!

Only 2,3,4 exist on the header, so only 3 is usable

Hi,
It detect IRQ5 as the tandy 1000 video use it...
So the picomem see it fired, but it is an error.
It will then try to use irq5 as picomem irq, but picomem 2 irq is hardcoded to irq5.

So, I have to mofify the firmwareto correct those things.

Once done, I should allow the emulated DMA to work at the same time as real dma.

Then, SB can work as well.

Picomem 1 has virtual dma working on the ex/hx.

You can also use mod master XT to use GUS. No need of dma/irq

FreddyV wrote on 2026-09-08, 14:54:

Hi, It detect IRQ5 as the tandy 1000 video use it... So the picomem see it fired, but it is an error. It will then try to use ir […]
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Hi,
It detect IRQ5 as the tandy 1000 video use it...
So the picomem see it fired, but it is an error.
It will then try to use irq5 as picomem irq, but picomem 2 irq is hardcoded to irq5.

So, I have to mofify the firmwareto correct those things.

That might explain the instabilities I was experiencing, especially when trying to use the PicoMEM 2 to increase the RAM on the machine. The test results of PICOMEM.EXE would sometimes fail, sometimes not, at some point I got random ASCII art filling the screen, sometimes I would have random lock-ups on the DOS prompt, and Monkey Island (the 16-color version) would always start up with a garbled screen and then quit with a heap corruption error. I would also get the garbled screen when forcing the game to run in CGA mode, just with only 4 colors of random pixels instead of 16.

Graphical applications that would work with 256KB or less ran fine, even with the PicoMEM 2 installed: Alley Cat with the Tandy patch and os8088.

Using only the PSRAM (and not the Pico's faster zero-waitstate RAM) for emulating all the RAM did appear to make the RAM tests of PICOMEM.EXE pass, but Monkey Island sill wouldn't run.

I also noticed the memory configuration in the PicoMEM 2 setup resetting or changing sometimes after a restart or power cycle.

Once done, I should allow the emulated DMA to work at the same time as real dma.

Then, SB can work as well.

Picomem 1 has virtual dma working on the ex/hx.

That would be pretty cool! Sound Blaster support on that machine would merely be a nice-to-have to me, since the on-board 3-voice synthesizer is the machine's charm, but it's still fun to play with.

I made some screenshots of the various PICOMEM.EXE test runs. Let me know if those are useful to share. Maybe I can have those results written to log files instead. Does PICOMEM.EXE have an option for that? Or maybe I can just redirect the output.

I'm currently running it with DR-DOS (SvarDOS), in case that matters.

Would it be possible to add Disney Sound Source (DSS) emulation to the PicoMEM 2, in addition to just Covox Speech Thing emulation? The Sound Source would be a period-correct sound device for this machine, which would compliment the 3-voice synthesizer well with buffered PCM output and some support in games that can run on PC/XT systems. And it requires neither IRQ nor DMA. You might be able to port the DSS emulation code from the Picovox firmware, which is based on the same microcontroller as the PicoMEM 2.

Happy to help with troubleshooting/debugging with any of this.

Thanks!

FreddyV wrote on 2026-09-08, 14:54:

Hi, It detect IRQ5 as the tandy 1000 video use it... So the picomem see it fired, but it is an error. It will then try to use ir […]
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Hi,
It detect IRQ5 as the tandy 1000 video use it...
So the picomem see it fired, but it is an error.
It will then try to use irq5 as picomem irq, but picomem 2 irq is hardcoded to irq5.

I got Monkey Island to run by adding a config.sys file to the root directory of the SD card with the following contents:

1IRQ 3
2TANDY 256

Gameplay seems fine, although the mouse doesn't work, even when I have PMMOUSE loaded. During boot, the PicoMEM2 does detect the Logitech mouse that I have plugged into its USB port.

I will try some other games or applications with mouse support, to see if that's just with this game.

Also, when I quit the game, it hangs in text mode with a blinking cursor, and sometimes the background weirdly starts changing colors. But gameplay itself seems fine, at least with the aforementioned configuration on the SD card.

mbandalauk wrote on 2026-08-08, 13:47:

Hi, […]
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Hi,

Has anyone tested the PicoMEM 2 with Sergey Kiselev's Micro 8088 computer? I am doing some testing with this setup, and almost everything works like a charm: Wi-Fi, HDD emulation, floppy emulation, sound, and RTC, except for the USB mouse. The PicoMEM 2 BIOS reports that a USB mouse device has been detected. Of course, I have played around quite a lot with the PM2 BIOS settings (USB Host: On, USB Joy: Off, etc.). My setup has no extra hardware, just the Micro 8088 (BIOS 1.02), Sergey's VGA card, and the PicoMEM 2. See the attached photo.

I have tried Freddy's own disk HDD images (D33_ENG.img and D622_500M.img). Both Microsoft's MOUSE.COM driver and CTMOUSE fail to detect the mouse. Oddly, PMMOUSE seems to detect and load a PS/2 mouse correctly, but unfortunately, the mouse itself does not work. I have also tested the bootable Svarog86 FreeDOS floppy image, but CTMOUSE fails to detect anything there too.

I have also tested older versions of the Micro 8088 BIOS, with the same result. I have tested several different mice as well. If you think I am missing something here, please let me know. Thanks!

Ah, so I'm not the only one who couldn't get PMMOUSE to work in a PC/XT class (8088 or V20) system. I did notice PMMOUSE printing a message on screen advising people with non-VGA systems to try another driver. But since @mbandalauk couldn't get it to work in a Micro 8088 with a VGA card either, that's not the problem,then. Did anybody else get a USB mouse to work on the PicoMEM 2 with PMMOUSE or any other mouse driver?

digger wrote on 2026-09-09, 21:14:

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1IRQ 3
2TANDY 256

While counterintuitive (given the IRQ 5 discrepancy), you'll need to remove that "IRQ 3" parameter in order for the mouse to work.

Picomem.exe is an early test testing hardcoded address, it is not relevant.

Cloudschatze wrote on 2026-09-10, 01:30:

While counterintuitive (given the IRQ 5 discrepancy), you'll need to remove that "IRQ 3" parameter in order for the mouse to work.

Thanks for that piece of advice! 😃 Indeed, that made the mouse work in my setup too. I've tested it with Monkey Island 1 (the 16-color version) and King's Quest IV (the SCI0 version).

Graphics, sound and mouse support was fine in both games, but the remaining issue is still that when I quit either game, the system hangs in text mode. Sometimes a blinking cursor on the upper left on the screen, sometimes a text-mode screen filled with random characters and CP437 glyphs with random foreground and background colors, some of them blinking. The system is then completely unresponsive. CTRL-ALT-DEL doesn't work at that point.

By the way @Cloudschatze, how did you mount your PicoMEM2 in your Tandy 1000 EX ? Did you use the same PLUS-to-ISA riser card from Tindie? Or did you find another solution? And how did you secure the card in the case?

@Cloudschatze use the latest test firmware adding CD.
I work to improve the IRQ code now.

digger wrote on 2026-09-10, 22:23:

By the way @Cloudschatze, how did you mount your PicoMEM2 in your Tandy 1000 EX ? Did you use the same PLUS-to-ISA riser card from Tindie? Or did you find another solution? And how did you secure the card in the case?

I'm using two PLUS-to-ISA adapters, along with a repurposed backplate from an RS-232 PLUS board to give the VGA card/connector some support. Not the greatest to look at, but it's fairly secure.