To dial back the snark a bit, the reason there’s an obsession with the Pico is many-fold. Nothing else combines the price, availability (these retro projects were started when the chip shortage was much worse), speed (overclockability of the RP2040 is legendary), interfacing ability of PIO, peripheral set, quality of SDK and developer tooling, and active community of the Pico and RP2040.

And the claim that the Pico can barely keep up with ISA is incorrect. The PicoMEM can simultaneously emulate RAM, HDD faster than XTIDE, and an NE2000. Not sure how that qualifies as “barely.”

Somewhat off-topic, but I wonder if it would be feasible to develop a CPU upgrade based on an RP2040 that would fit in an 8088 or 8086 slot (and perhaps also in the 8087) slot) and would emulate an 386 CPU (or perhaps even something faster), including more (and faster) RAM, while still using the host machine for everything else I/O-wise. Something like those unobtanium 286 accelerator boards, but much cheaper and even faster.

I think I'll open a separate topic for this.

digger wrote on 2023-11-27, 16:09:

Somewhat off-topic, but I wonder if it would be feasible to develop a CPU upgrade based on an RP2040 that would fit in an 8088 or 8086 slot (and perhaps also in the 8087) slot) and would emulate an 386 CPU (or perhaps even something faster), including more (and faster) RAM, while still using the host machine for everything else I/O-wise. Something like those unobtanium 286 accelerator boards, but much cheaper and even faster.

I think I'll open a separate topic for this.

Well, yes, it has essentially already been done. A raspi is not even required.
https://microcorelabs.wordpress.com/2022/02/0 … and-challenges/
https://microcorelabs.wordpress.com/2022/07/3 … lerator-update/

Would a RP2040 be able to handle a 16 bit ISA bus? While I got an old XT that's been sitting around since 1990, I don't do a lot on it. 286's and 386's are much more interesting to me.

douglar wrote on 2023-11-27, 18:34:

Would a RP2040 be able to handle a 16 bit ISA bus? While I got an old XT that's been sitting around since 1990, I don't do a lot on it. 286's and 386's are much more interesting to me.

hi,

Some of the early PicoMEM useres told me that also on 386, it is really usefull.
16Bit will "Only" add more speed.

Also, It will not possible to use the 0 Wait State of the 16Bit ISA, then loosing most of the interrest of the 16Bit.

FreddyV wrote on 2023-11-28, 12:36:

[Some of the early PicoMEM useres told me that also on 386, it is really usefull.
16Bit will "Only" add more speed.

Isn't that often the catch with retro computing? I always want to push the performance & features of my old hardware, but at the same time, if performance & functionality are the ultimate goal, why not jump ahead to newer of hardware that has better performance & features ? And if you had said that 16-bit wasn't a problem, I'd have probably asked about VLB support.

I'd use it for the features even if it stays 8 bit.

The rom support sounds great. Writing and re-writing option roms for a quick test is a pain and those pins on those old chips don't get any more sturdy with each reinsertion.
I have a KVM switch that only does PS/2 mouse support. Would "PiPico on ISA" work with a PS/2 to USB active adapter for a keyboard and mouse?
I'd be interested in the floppy support except I'm not sure I want to give up the tiny OLED on my Gotek in most use cases.

Example of a PS/2 to USB active adapter for a keyboard and mouse:

polpo wrote on 2023-11-27, 13:05:

kingcake wrote on 2023-11-27, 00:57:

I don't understand the obsession with the PI Pico for these projects. Often the projects are limited by the Pico's performance. It can just barely handle software defined ISA. There are way more powerful microcontrollers out there that are plentiful and an order of magnitude cheaper.

Please tell me about a microcontroller that is 10 cents and is more powerful than the RP2040.

Show me a Pi Pico unit that costs 10 cents. You're operating in bad faith.

kingcake wrote on 2023-11-28, 15:54:

polpo wrote on 2023-11-27, 13:05:

kingcake wrote on 2023-11-27, 00:57:

I don't understand the obsession with the PI Pico for these projects. Often the projects are limited by the Pico's performance. It can just barely handle software defined ISA. There are way more powerful microcontrollers out there that are plentiful and an order of magnitude cheaper.

Please tell me about a microcontroller that is 10 cents and is more powerful than the RP2040.

Show me a Pi Pico unit that costs 10 cents. You're operating in bad faith.

I'm sorry, I assure you I'm not operating in bad faith. You said "There are way more powerful microcontrollers out there that are plentiful and an order of magnitude cheaper." The RP2040 microcontroller costs $1. An order of magnitude cheaper would be $0.10. Or if you're talking about the Pico specifically, that's $4 so an order of magnitude cheaper would be $0.40. I don't know of any microcontrollers that are anywhere near those price points that are as capable as the RP2040/Pico, let alone more powerful than it. There may be some RISC-V microcontrollers that get close that do hold a lot of promise, but in my opinion they're held back by lower-quality SDKs and tooling.

douglar wrote on 2023-11-28, 13:22:

The rom support sounds great. Writing and re-writing option roms for a quick test is a pain and those pins on those old chips don't get any more sturdy with each reinsertion.
I have a KVM switch that only does PS/2 mouse support. Would "PiPico on ISA" work with a PS/2 to USB active adapter for a keyboard and mouse?
I'd be interested in the floppy support except I'm not sure I want to give up the tiny OLED on my Gotek in most use cases.

I still need to add ROM image file loading.
This is of course to help for extention ROM development, and why not it may inspire ppls to do expansion ROM games or apps.
Or simply to test different XTIDE BIOS

You can still use a Gotek, if no floppy image is selected, the physical drive is used.
Pi Pico based boards doing USB to PS/2 and XT already exist:
https://github.com/No0ne/ps2pico

FreddyV wrote on 2023-11-28, 22:48:

You can still use a Gotek, if no floppy image is selected, the physical drive is used.
Pi Pico based boards doing USB to PS/2 and XT already exist:
https://github.com/No0ne/ps2pico

Gotek devices work fine once you get flash floppy working i guess. It would be tough to match that level of functionality with an add-in card becuase the Gotek solution gives you a front access port with oled display which both have value to me.

That’s a nifty project to connect the usb devices to a ps/2 port, if I read the notes correctly. I found a different way to do that. I was able to pick up an HP AF617a KVM switch on the cheap that does the same thing. I can plug USB devices into the switch and use them on computers with PS/2 ports.

My problem is that I have not found any affordable interface modules for it that support serial mice, so that’s why I’m looking for ways to add a PS/2 mouse port to older PC’s. If the pico supports the ps/2 —> usb adapters, then it could provide PS/2 ports.

Hi,

I had to correct 2 little things on the PicoMEM 1.1
So here is the 1.11:

Glad you are making progress on it. Let me know if you need any help testing.

One last note about mouse functionality. There's certainly a demand for something that works with a KVM switch via PS/2 or USB after these stopped being available last year: Re: Another PS/2 Mouse ISA (ISA8) card adapter

Where can you buy it?

FreddyV wrote on 2023-12-07, 20:08:

Hi, […]
Show full quote

Hi,

I had to correct 2 little things on the PicoMEM 1.1
So here is the 1.11:

PicoMEM111.png

Support for SD and WIFI is excellent, even if the memory is increased.
For 386 and 486 would it work?

Eben Upton hinted that rpi is working on another chip with more PIO, GPIO, and a bigger Cortex-M chip... whenever that comes out 16-bit ISA shouldn't be a problem, but the chip will likely need to be directly integrated to the board.

(I really want 480Mb USB myself, but I don't know if that'll happen. reply-edit: I meant in general for other possible projects I want to do - 12Mb USB is fine for this application. If you want things to go fast you're not using anything that supports 8bit ISA 😉 )

And the RP2040 definitely has a unique balance of price and capability - how many microcontrollers can bit-bang DVI?

happycube wrote on 2023-12-09, 13:16:

(I really want 480Mb USB myself, but I don't know if that'll happen)

In practice, a USB 1.1 device can read data at about 0.8 MB/s but a USB 2.0 device is 20x faster, and can read data at up to 15MB/s
In practice, 8 bit ISA cards can handle up to 1.0 MB/s in the best case, and a 16 bit ISA card is going to be 2x faster, but twice a small number is still a small number, and it's going to be an order of magnitude short of USB 2.0.

If you have some excellent drivers, you could probably keep up with a USB 1.1 device on an 8bit card, and you could copy 256MB of files in 6 minutes or so. That's adequate for just about all retro applications, so I can see why FreddyV is sticking with 8 bit cards. If you need speeds faster than 1 MB/s, 16 bit ISA isn't going to be close to competing with carrying removable media over to a contemporary computer and loading it at max media speed.

Now in theory, a VLB device with a bus master driver could possibly get close to USB 2.0 speeds, but VLB was always kind of a small niche, and VLB was never kind to adding additional devices.

Livingstone wrote on 2023-12-09, 11:41:

Where can you buy it?

Hi,

I answered so many time already 😀

I produce some boards only for the moment, I send to ppls following me.
For a production with more volume, the software is not mature enaugh and I still don't know how to do.

Well, I would like to sign up
I have a 486 with Vesa Local Bus, and an ISA card would be the solution to many of my data transfer problems.

Livingstone wrote on 2023-12-16, 14:38:

Well, I would like to sign up
I have a 486 with Vesa Local Bus, and an ISA card would be the solution to many of my data transfer problems.

Hi,

it was tested to work on a 486, but it is not currently the main focus.
Then, it should not work on most of them.

This would be nice to replace some things on my Model 30 8086 system.
Using the lotech 2mb EMS card and XIRCOM LPT network adapter.

I waaaaant 😀