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A 386 PC for Your RP2350

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Re: A 386 PC for Your RP2350

#71

Post by IshKebab »

willis936 wrote: post #19
IshKebab wrote: post #17

Earlier quoted context omitted.

Overrated surely? It's a pretty bog standard MCU, no wireless support, mediocre deep sleep. I don't know why you'd pick it over an ESP32 or nRF5x. The only standout feature is PIO which is definitely interesting but very niche. It's also patented so say goodbye to any portability or FOSS vibes. (If you want a FOSS version btw, check out https://baochip.com/ ) If it didn't have the Raspberry name behind it nobody woul…

The PIO are pretty great and not niche. Almost any embedded application needs mixed signal interfaces. You could say embedded applications are niche, but not that embedded applications needing mixed signal interfaces. A serious warning: read the RP2350 errata carefully. You may be better off buying old 2040 inventory.

> Almost any embedded application needs mixed signal interfaces.

For the vast majority of embedded applications you can simply pick an MCU that has the hardware peripherals they need. That's why XMOS was never very successful. (They thought of this idea long ago.) Not saying it isn't cool.

Re: A 386 PC for Your RP2350

#72

Post by IshKebab »

riskable wrote: post #27
IshKebab wrote: post #17

Earlier quoted context omitted.

Overrated surely? It's a pretty bog standard MCU, no wireless support, mediocre deep sleep. I don't know why you'd pick it over an ESP32 or nRF5x. The only standout feature is PIO which is definitely interesting but very niche. It's also patented so say goodbye to any portability or FOSS vibes. (If you want a FOSS version btw, check out https://baochip.com/ ) If it didn't have the Raspberry name behind it nobody woul…

Are you kidding me? It costs a fraction of the competition and you can use just about any pin for anything you want! It makes designing boards for the RP series so simple and easy! Contrast that with STM32 where you have to constantly reference the data sheet to make sure you're using the correct pins for say, I2C when you're running in a particular mode. And since you're running in that mode, you now can't use other…

nRF5x also has completely configurable pins, and if you're worrying about awkward pinouts making PCB design slightly more annoying then you're definitely not in a cost sensitive project.

Re: A 386 PC for Your RP2350

#73

Post by dark-star »

ilaksh wrote: post #54

The problem is PC programs assume 640kb of RAM and the RP2350 has 512kb + 16kb cache SRAM so anything that goes past that has a sudden 40 cycle access delay. So even if you account for the RP2350 being 6 times faster than the RP2350, I think the emulation would randomly start to stutter a lot in certain circumstances waiting to access that part of the memory.

How is the RP2350 6 times faster than the RP2350? That must be a typo...

Re: A 386 PC for Your RP2350

#74

Post by dark-star »

ilaksh wrote: post #63
Narishma wrote: post #61

Earlier quoted context omitted.

The boards using this chip typically have 8 MB of PSRAM from what I've seen.

yeah but the PSRAM is going to cause a delay

it's not that bad. At 120MHz, the PSRAM still gets only around 90-100ns per word in the worst case. If you use some SRAM for caching and do bulk transfers, you can get that down quite a bit. Also you can easily overclock the PSRAM to 133MHt (10 decrease in latency) with no problem, maybe even (much?) more.

normal dynamic RAM back then was at 60-70 ns so it's really not that bad. And YT videos show that it also works fine in practice

Re: A 386 PC for Your RP2350

#75

Post by dark-star »

kees99 wrote: post #18
burstmode wrote: post #12

Does it emulate RS232 ports and printer ports as well ? I did'nt find anything. Then it would be possible to reuse old embedded equipment.

No, it doesn't. Also this doesn't emulate ISA bus, where one could plug one of those "multi-io" cards to get rs232/printer ports. Which is a shame. There are plenty of GPIO pins to fit full ISA on RP2350 (at least on "B" variant), and those GPIO are supposedly 5V-tolerant (with sufficiently recent silicon revision). So hardware-wise, it's just a matter of wiring up an ISA slot directly to the RP chip.

it would be awesome if there was an ISA bus emulation using some sort of modern protocol. You could create "modern" ISA cards using an RP2350 on every card that does the emulation, to split emulation between multiple RP2350's (one emulates a VGA card, one emulates a sound card, one emulates a network card, etc.)

Bonus points for a standardized connector that everyone could develop towards. Imagine a tiny ISA PC that you could place on your desktop, swap miniscule (ISA)-cards in and out of, and play retro games etc.

Re: A 386 PC for Your RP2350

#76

Post by dark-star »

momocowcow wrote: post #5

yes, but those screenshots are EGA

At least the Wolfenstein screenshot is VGA, not EGA. Yes, it looks weird with that dithering effect, but it's still VGA (too many/wrong colors for EGA, and also: Wolfenstein never was released with EGA graphics in the first place)

Re: A 386 PC for Your RP2350

#78

Post by luma »

ilaksh wrote: post #66
luma wrote: post #65

Earlier quoted context omitted.

That isn't true to my knowledge for old DOS applications (including games). 640kb was the upper limit, not the lower bound.

yeah but for 386?

Same answer. You could enter 386 protected mode with less than 640kb installed.
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