FreddyV wrote on 2025-12-17, 18:23:

Hi, […]
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Hi,

Still working on the PicoMEM 2, probably not available before March next year (Will send this board to prod next week and hope it work)

The attachment PicoMEM2.png is no longer available

I confirmed the DMA is working and even got GUS mixing working (No DMA support Yet) plus Sound Blaster (With DMA) working.

Here is an audio output of the PicoMEM 1.5 GUS:

The attachment Solstice_PicoMEM_GUS_Mono.mp3 is no longer available

I imagine this is with the RP2350

carlostex wrote on 2026-01-05, 14:00:

FreddyV wrote on 2025-12-17, 18:23:

Hi, […]
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Hi,

Still working on the PicoMEM 2, probably not available before March next year (Will send this board to prod next week and hope it work)

The attachment PicoMEM2.png is no longer available

I confirmed the DMA is working and even got GUS mixing working (No DMA support Yet) plus Sound Blaster (With DMA) working.

Here is an audio output of the PicoMEM 1.5 GUS:

The attachment Solstice_PicoMEM_GUS_Mono.mp3 is no longer available

I imagine this is with the RP2350

From the pincount this looks a RP2350 B. The RP2350A and RP2040 have a smaller case with only 15 pins per side.

I am very interested in these features for DOS:

- Memory emulation with 16Kb Address granularity:
> 128Kb of RAM can be emulated from the Pi Pico internal RAM with No Wait State. (4MHz ISA)
> We can emulate the whole 1Mb of RAM address space from the PSRAM. (With 6 Wait Stated for 4MHz ISA)
> EMS Emulation of Up to 6 / 7 MHz. (Only 4Mb for the moment as using the LoTech EMS Driver)
> Memory emulation is also used to add (4Kb of "Private" memory for the PicoMEM BIOS Usage)
> 16Kb of RAM is also added for disk access (Or other) even if 512Kb only is used for the moment.

I have an issue with trying to use UMBs on motherboards and either not being able to find enough or having them conflict with motherboard resources, leading to instability. Would something like this create a UMB "mask" over the motherboard's main UMBs (memory over 640K) that is guaranteed to be safe for programs to load into completely?

For example, I have an industrial socket 775 motherboard which has unusable UMBs in DOS, unless I disable USB 2.0 in the BIOS. And even then, I feel like I'm fighting for memory above 640K. I would love for there to be a way to reclaim UMBs for my drivers without sacrificing motherboard features that I want available in other operating systems.

lausvi wrote on 2024-08-23, 17:17:

I now have another question! I have a Commodore PC-I (https://www.zimmers.net/cbmpics/cpci.html), which I think would really ben […]
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I now have another question! I have a Commodore PC-I (https://www.zimmers.net/cbmpics/cpci.html), which I think would really benefit having a PicoMEM: it only has one ISA-slot (and only by using an external adapter: https://autumnhippo.com/products/pc1-xt) and it's very low-end XT clone. Having a hard disk, AdLib and networking on it would be a really neat treat (also no need for the bracket, hah).

I installed the PicoMEM on my PC-I and it does work (hard disk, AdLib and networking tested so far) BUT there is a somewhat random issue where sometimes (most of the time actually) the machine freezes at "PicoMEM Boot: Press A to boot from floppy , B for BASIC/ROM 1". The count-down at the end of the line stops at 1 or 2. At this point the internal floppy-drives's light is on, and when the boot halts, the light stays on (when it boots succesfully, the floppy drive light goes off after the hard disk boot has started). If I keep resetting the computer, I eventually get it to boot succesfully either by just not touching the keyboard at all, or bashing keys on the prompt and it just proceeds normally. I had no issues with the PicoMEM itself as I tested it on a loose 386 motherboard.

I noted some mentions of a timing issue with Commodore PC-10, could this be something similar (what was the issue on that machine?). Or as mentioned in a recent issue on the GitHub (https://github.com/FreddyVRetro/ISA-PicoMEM/issues/41) perhaps a power issue? Are there any easily reachable spots on the PicoMEM PCB to add additional capacitor for testing?

I did see couple of times an error about config not being saved/SD card not accessible, could this be a power issue as well? (The SD card is new and freshly formatted, although a cheap 4GB one).

Regarding my own issue way back in 8/2024: I've now tested the same setup again with the currently latest firmware and I haven't had a single issue booting the computer. So something released after late 2024 seems to have fixed, or at least greatly reduced, the halting-countdown issue I had with my PC-1.

Having a PicoMem adding an XTIDE bootable hard drive, an AdLib audio and NE2000 networking is a great addition for the otherwise very limited PC1 👍