Olimex board seems to be available right now though.
kevin42 · 4h ago
I think this is a really cool project, but the problem with putting so many peripherals on such a small processor is that it's really tough to have firmware that uses all of those things at once and fit in the memory footprint.
I can see this as a great platform for prototyping though.
crest · 3h ago
The memory footprint is 520kiB of SRAM + 8MiB of QSPI RAM + 16MiB of QSPI flash. What kind of bloated monstrosity do you want to run on that poor board?
Lerc · 3h ago
Once you have video out, Memory eating options become quite available. Framebuffers are quite large.
I've got a 1.4inch screen waveshare rp2350 sitting beside me at the moment. I'm currently fighting getting paletted display update via DMA with limited success. As I work through it it does become apparent to me that you could generate a tiled+sprites mode a scanline at a time on demand with PIO and DMA. I'm not convinced it could be run with zero CPU involvement, but it could certainly be done with very little CPU.
raphlinus · 1h ago
For 640x480 output not overclocked, I estimate tile + sprite CPU utilization to be about 50% of one core. Of course you have two cores. That number goes up and down depending on resolution, particularly when you're pixel doubling.
It's absolutely doable. There's the beginning of a tile demo (a scrolling brick wall) in the pico-dvi-rs repo.
Retr0id · 4h ago
Huh, according to the schematic the USB hub upstream port is routed to the D+/- pins on the rp2350. How does that work? I thought the only way a rp2350 could act as a USB host was via PIO?
15155 · 2h ago
> I thought the only way a rp2350 could act as a USB host was via PIO?
With the vendor SDK driver, yes. The controller can operate in Host mode if you BYO driver.
rasz · 3h ago
rp2350 has 'USB 1.1 controller and PHY, with host and device support'. Plugging powered cable to USB-C should keep HUB in reset.
raphlinus · 3h ago
This looks really cool, I ordered one. I'm also waiting for the Fruit Jam, mentioned elsethread.
The pico-dvi-rs project has an early prototype of race-the-beam video generation, which I think has a lot of potential, it's going to allow much richer content than a framebuffer on this kind of device. One fun thing we've got going is proportionally spaced bitmap fonts, which is fairly unusual in this form factor. Please get in touch with me if you're interested in driving this thing with Rust.
That's a lot of stuff connected to the one RP2350.
I can't help but feel that you could make almost the same board with 2 or 4 RP2350's without a significant percentage increase in cost.
Couldn't you wire most of the GPIOs together, they start off at high impedance, then let them work out who does what with plenty of options for weird processor sharing arrangements.
I guess if it's open source, I could take a look at doing one myself. What's the worst that could happen :-)
15155 · 2h ago
> Couldn't you wire most of the GPIOs together, they start off at high impedance, then let them work out who does what with plenty of options for weird processor sharing arrangements.
This is a ton of software to build.
Fast Linux-capable SOCs are only $5 with 100x+ the specs.
Lerc · 1h ago
You don't play with these things for the raw performance. I'd get a quad rp2350 just so I could have a go at writing the software for such a weird architecture.
There are heaps of boring off the shelf options.
joezydeco · 1h ago
I'm playing with the 2040/2350 because it's dirt cheap. A Pico2W with BT/Wifi is $7 from Adafruit.
I'm working on a project where we might just hand these to customers for a certain function and consider them disposable when the work is done.
chaosprint · 3h ago
very cool.
But I don't understand why ES8311 mono audio codec is used here.
I recently successfully run Glicol (https://github.com/chaosprint/glicol) on Pico 2 and I am building a prototype board for myself. AIC3204 is my first choice for now and it's not that expensive
rasz · 3h ago
>Stereo Audio Codec with Stereo Audio Amplifier
uses ES8311 'Low Power Mono Audio CODEC' http://www.everest-semi.com/pdf/ES8311%20PB.pdf, Mono DAC with differential output. I dont even understand why someone would do that, yes its a $.3 part but real stereo codec from TI (TLV320AIC320x) is just $.6
Edit: looking at BOM it might be caused by Made in China 2025 and trying to get as close to 100% domestic part list for some subsidies.
I can see this as a great platform for prototyping though.
I've got a 1.4inch screen waveshare rp2350 sitting beside me at the moment. I'm currently fighting getting paletted display update via DMA with limited success. As I work through it it does become apparent to me that you could generate a tiled+sprites mode a scanline at a time on demand with PIO and DMA. I'm not convinced it could be run with zero CPU involvement, but it could certainly be done with very little CPU.
It's absolutely doable. There's the beginning of a tile demo (a scrolling brick wall) in the pico-dvi-rs repo.
With the vendor SDK driver, yes. The controller can operate in Host mode if you BYO driver.
The pico-dvi-rs project has an early prototype of race-the-beam video generation, which I think has a lot of potential, it's going to allow much richer content than a framebuffer on this kind of device. One fun thing we've got going is proportionally spaced bitmap fonts, which is fairly unusual in this form factor. Please get in touch with me if you're interested in driving this thing with Rust.
[1]: https://github.com/DusterTheFirst/pico-dvi-rs
I can't help but feel that you could make almost the same board with 2 or 4 RP2350's without a significant percentage increase in cost.
Couldn't you wire most of the GPIOs together, they start off at high impedance, then let them work out who does what with plenty of options for weird processor sharing arrangements.
I guess if it's open source, I could take a look at doing one myself. What's the worst that could happen :-)
This is a ton of software to build.
Fast Linux-capable SOCs are only $5 with 100x+ the specs.
There are heaps of boring off the shelf options.
I'm working on a project where we might just hand these to customers for a certain function and consider them disposable when the work is done.
uses ES8311 'Low Power Mono Audio CODEC' http://www.everest-semi.com/pdf/ES8311%20PB.pdf, Mono DAC with differential output. I dont even understand why someone would do that, yes its a $.3 part but real stereo codec from TI (TLV320AIC320x) is just $.6
Edit: looking at BOM it might be caused by Made in China 2025 and trying to get as close to 100% domestic part list for some subsidies.