Sphere478 wrote on 2025-02-19, 06:27:

I was wondering about if the pi pico could interface with 386/486 cpu bus. Not isa (similar to vl bus)

No, not really
For what concerns 386/486, there are lot of period accurate solutions. (Use real RAM sim ? )

Will it be possible in the future to flash new firmware via PMINIT or some other utility? That would certainly come in handy if/when BOOTSEL stops working.

FreddyV wrote on 2025-02-19, 13:32:

Sphere478 wrote on 2025-02-19, 06:27:

I was wondering about if the pi pico could interface with 386/486 cpu bus. Not isa (similar to vl bus)

No, not really
For what concerns 386/486, there are lot of period accurate solutions. (Use real RAM sim ? )

What is real ram sim?

So you mean just use simms?

Some mobos didn’t have cache. But it might be addable via the cpu bus if it were tapped.

OPLx wrote on 2025-02-20, 14:11:

Will it be possible in the future to flash new firmware via PMINIT or some other utility? That would certainly come in handy if/when BOOTSEL stops working.

Hi,

No, to flash the ROM, the code need to be 100% in RAM, then, no more possible to execute disk code to read the data...
PicoMEM emulate too many things to have all in RAM (Obviously)

PicoGUS is a set of minimal code all running in RAM
This was done because we can't overclock the Pico1 more than 280MHz with ROM Active
It is now possible on the Pico2 😀

FreddyV wrote on 2025-02-22, 11:20:

This was done because we can't overclock the Pico1 more than 280MHz with ROM Active
It is now possible on the Pico2 😀

Speaking of the Pico 2, should I hold off on purchasing a (preassembled) PicoMEM, until a newer PicoMEM based on the Pico 2 becomes available?

The system I'm upgrading has 256KB of on-board memory, and I would like to max out the conventional, upper and expanded memory that the machine can support, with 0 wait states.

This is an ongoing hobby project, and I'm not in a hurry, so I'd be willing to wait if such a "PicoMEM 2" is on the horizon.

I'm aware that that there is also the Teensy-based XTMax project, but that card apparently(?) does not support UMB, nor other features of the PicoMEM (sound, networking, mouse support, etc).

Thanks.

PicoMEM does have sound, networking, and mouse, however the compromise is that only provides conventional memory with many wait states, only 4 MB of expanded RAM, and MicroSD which requires you to use disk images instead of simply copying files to/from the card. It also does not support DMA so you will not be able to use your physical floppy disk or hard drive with PicoMEM emulating any conventional RAM.

XTMax focuses on supporting the full 640 KB (which can be increased into UMB) of conventional RAM with zero wait states, 16 MB of expanded RAM, and normal MicroSD usage with no disk images. It "Maxes" out its functionality with no compromise and is not spread thin with other features.

Thanks for the info, @MicroCoreLabs.

It looks like at least for maxing out the various kinds RAM, the XTMax would indeed be the way to go. And then perhaps add the PicoMEM for the mouse, game controller and network support.

To be fair, the machine that I'm upgrading, a Tandy 1000 EX, doesn't have a built-in DMA controller. It could optionally be upgraded with one, but that requires a proprietary and rare upgrade card, which I don't have. So I assume that this machine's physical floppy drive, driven by the BIOS in non-DMA mode, would likely be able to work with the emulated RAM that the PicoGUS could provide, even though it lacks DMA support.

But even then, the multiple wait states still wouldn't make it an appealing option.

@FreddyV I'm still wondering what the plans are for a Pico2-based "PicoMEM 2", and what capabilities and potential such a card would have. Likely, it would be fast enough to offer all RAM without wait states, right? I take it that you are a bit hesitant to go into detail about that, to prevent the Osbourne Effect? 😉

Anyway, I'm definitely interested in acquiring an XTMax card. Let's discuss that further in the XTMax thread.

OPLx wrote on 2025-02-18, 13:42:

Yoghoo wrote on 2025-02-18, 13:24:

How exactly are you doing it? You need to remove the PicoMEM from the motherboard (can't stay in the computer even when powered down). Then attach the USB cable to the PicoMEM, press the BOOTSEL button and then attach the USB cable to your desktop. Keep the BOOTSEL button pressed the whole time btw until a drive pops up on your desktop else it will not work. After that you should be able to drag and drop the new firmware on that drive. When it's done it will automatically dismount the drive.

If the BOOTSEL button is broken somehow you need to solder some pins on the PICO and do it via serial or so.

Sorry about that, I should have mentioned what I did. After the PicoMEM arrived, I took it out of the packaging, held down BOOTSEL and plugged the USB connector into my PC, but no response. I have a separate Pico, Pico W, and Pico2 and those worked without any BOOTSEL problems, so I'm not exactly sure what could be wrong. Since the PicoW is soldered directly onto the PicoMEM, it's not possible to access TP6 on the back to get around the issue.

I don't know why this is but you just have to keep trying. I don't know why this is such an issue but I also have this issue that the Pico is unresponsive over USB. I just keep trying over and over until it works. Also make sure you are using a USB cable that supports data.

FreddyV wrote on 2025-02-22, 11:20:

Hi, […]
Show full quote

OPLx wrote on 2025-02-20, 14:11:

Will it be possible in the future to flash new firmware via PMINIT or some other utility? That would certainly come in handy if/when BOOTSEL stops working.

Hi,

No, to flash the ROM, the code need to be 100% in RAM, then, no more possible to execute disk code to read the data...
PicoMEM emulate too many things to have all in RAM (Obviously)

PicoGUS is a set of minimal code all running in RAM
This was done because we can't overclock the Pico1 more than 280MHz with ROM Active
It is now possible on the Pico2 😀

I figured it would likely not be possible, but I thought I would ask anyway 😁 Looking forward to the possible Pico2 version! Thank you for making PicoMEM!

megatog615 wrote on 2025-02-24, 02:47:

I don't know why this is but you just have to keep trying. I don't know why this is such an issue but I also have this issue that the Pico is unresponsive over USB. I just keep trying over and over until it works. Also make sure you are using a USB cable that supports data.

Thanks for the suggestion and encouragement! I know it's not the USB cable since the cable works with the other standalone Picos I have. It looks like I will have to de-solder the Pico W and replace it when I have ample time (and the proper tools). At least the PicoMEM works on the host computer.

digger wrote on 2025-02-22, 17:33:

Speaking of the Pico 2, should I hold off on purchasing a (preassembled) PicoMEM, until a newer PicoMEM based on the Pico 2 beco […]
Show full quote

FreddyV wrote on 2025-02-22, 11:20:

This was done because we can't overclock the Pico1 more than 280MHz with ROM Active
It is now possible on the Pico2 😀

Speaking of the Pico 2, should I hold off on purchasing a (preassembled) PicoMEM, until a newer PicoMEM based on the Pico 2 becomes available?

The system I'm upgrading has 256KB of on-board memory, and I would like to max out the conventional, upper and expanded memory that the machine can support, with 0 wait states.

This is an ongoing hobby project, and I'm not in a hurry, so I'd be willing to wait if such a "PicoMEM 2" is on the horizon.

I'm aware that that there is also the Teensy-based XTMax project, but that card apparently(?) does not support UMB, nor other features of the PicoMEM (sound, networking, mouse support, etc).

Thanks.

Hi,

With a Pimoroni pico plus 2 on an actual PicoMEM, it adds 256Kb with no wait state and can use the PSRAM with one wait, or no wait on some PC
even more than 300Kb with no wait state is possible, but I would like to use more RAM for applications

OPLx wrote on 2025-02-24, 09:19:

Thanks for the suggestion and encouragement! I know it's not the USB cable since the cable works with the other standalone Picos I have. It looks like I will have to de-solder the Pico W and replace it when I have ample time (and the proper tools). At least the PicoMEM works on the host computer.

Hi,

One time I had a Pico not working and was able to "Unlock" it by programming it with the arduino environement.
You should check for pi pico support ?

FreddyV wrote on 2025-02-26, 09:13:

Hi,

With a Pimoroni pico plus 2 on an actual PicoMEM, it adds 256Kb with no wait state and can use the PSRAM with one wait, or no wait on some PC
even more than 300Kb with no wait state is possible, but I would like to use more RAM for applications

That's definitely an improvement worth waiting for. So the Pimoroni pico plus 2 could be soldered onto an existing PicoMEM board? It doesn't require a new board design?

And is there already a firmware that offers this improved functionality when a pico 2 is installed on the board?

Thanks.

digger wrote on 2025-02-26, 15:29:

That's definitely an improvement worth waiting for. So the Pimoroni pico plus 2 could be soldered onto an existing PicoMEM board? It doesn't require a new board design?

And is there already a firmware that offers this improved functionality when a pico 2 is installed on the board?

Thanks.

Hi,

Only a modified firmware is needed.
The public firmware source already support the Picoroni pico plus 2, I just did not published a compiled versioin.
As it add only Zero wait state RAM and faster PSRAM, it is not really worth the cost difference (Pimoroni pico plus 2 is expensive)
I did not test the Wifi and therea re USB problems.

I really don't know if I will release it as a new board design is in progress

FreddyV wrote on 2025-02-26, 22:03:

Hi, […]
Show full quote

Hi,

Only a modified firmware is needed.
The public firmware source already support the Picoroni pico plus 2, I just did not published a compiled versioin.
As it add only Zero wait state RAM and faster PSRAM, it is not really worth the cost difference (Pimoroni pico plus 2 is expensive)
I did not test the Wifi and therea re USB problems.

I really don't know if I will release it as a new board design is in progress

Got it. Thanks for the update.

By the way, would another RP2350-based microcontroller board work as well? For instance the Raspberry Pi Pico 2, or the Adafruit Feather RP2350, etc? Any reason why it would specifically have to be the Pimoroni Pico Plus 2?

Thanks again.

digger wrote on 2025-02-28, 14:28:

Got it. Thanks for the update.

By the way, would another RP2350-based microcontroller board work as well? For instance the Raspberry Pi Pico 2, or the Adafruit Feather RP2350, etc? Any reason why it would specifically have to be the Pimoroni Pico Plus 2?

Thanks again.

The difference between the Pimoroni Pico Plus 2 W and the RPi Pico 2 W is the 8 MB of PSRam added to the back, doubling the cost (which is rather cheap). The Feather RP2350 is the wrong form factor that limits the pins needed.

That said, 8 MB for EMS memory? Sounds great! Now to get it in a form factor for the Book8088/Pocket386...

FreddyV wrote on 2025-02-26, 12:42:

Hi,

One time I had a Pico not working and was able to "Unlock" it by programming it with the arduino environement.
You should check for pi pico support ?

I'll have to give this a try. Thankfully I have an arduino to attempt it with. Thank you for the suggestion!

NightShadowPT wrote on 2025-01-29, 08:23:

Hi! […]
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Hi!

I recently bought the "PicoMEM - Audio Edition" version from Serdashop, but I seem to be having trouble getting it to work on my Olivetti PC1.

When I use it on one of the ISA slots, it halts the memory test with a "Fail:08:1000:43BC:43BC:43FC", followed by a clear screen, change in resolution and a message "I/O CHECK error on expansion board 00".
If I try it on the other ISA slot, I get the error "Low Memory Fail", even before going into the boot screen.

I have attached photos for reference.

Any idea of what I can do diferently?

Thanks

Hi!

Just checking if anyone has any experience with the Olivetti PC1, or at least have any educated guesses about what the problem might be?

Thanks

digger wrote on 2025-02-28, 14:28:

Got it. Thanks for the update. […]
Show full quote

FreddyV wrote on 2025-02-26, 22:03:

Hi, […]
Show full quote

Hi,

Only a modified firmware is needed.
The public firmware source already support the Picoroni pico plus 2, I just did not published a compiled versioin.
As it add only Zero wait state RAM and faster PSRAM, it is not really worth the cost difference (Pimoroni pico plus 2 is expensive)
I did not test the Wifi and therea re USB problems.

I really don't know if I will release it as a new board design is in progress

Got it. Thanks for the update.

By the way, would another RP2350-based microcontroller board work as well? For instance the Raspberry Pi Pico 2, or the Adafruit Feather RP2350, etc? Any reason why it would specifically have to be the Pimoroni Pico Plus 2?

Thanks again.

I used the Pimoroni pico plus 2 to implement its PSRAM (Fast access in QSPI)
Other boards has absolutely no advantage and interrest

Hi,

I published the latest #PicoMEM firmware.

This one is a huge step for the board as it can now use USB Drive, plus MicroSD as a "Network" like drive.
Then, it has Full access to the disks in FAT32/ExtFS from DOS.

USB Disk can be removed at any time, to copy files to the PC from a modern PC.
No more need to extract the SD to copy a file or program.

You can also edit the PicoMEM config file, Wifi setup file, and copy/rename floppy image from DOS.

https://github.com/FreddyVRetro/ISA-PicoMEM

You can see a demo in video here :
https://x.com/FreddyVETELE/status/1894861569231901111