Raspberry Pi Pico & RP2040 boards

you can use USB-C jacks without a PHY just by providing two pullup resistors, it’s pretty great!

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I’m not sure that’s “legal” according to the USB specs. IIRC, a major vendor can’t offer it like that. The USB-C jack is only permitted according to USB 3.0 and higher standards. If you don’t support the additional signalling (to at least communicate that only USB 1.1 is supported, for instance) I don’t think you are within the spec.

my understanding is that if the cc1/cc2 pins are set correctly for power delivery (ie, upstream) then the dn/dp pins exist pretty explicitly to support usb 2.0/1.1 — the market is already flooded with passive cable/jack converters so it seems the standard should have anticipated this. i guess i need to go read some more specs, though.

Yeah, I’m the idiot who brought up the 3.2 and caused a cloud of confusion. @infovore is right, there’s a lot missing on the pico that the 3.2 has built in. The dual core is interesting but I’ve fooled about with the ESP32 and it’s a level of complexity that I haven’t quite gotten my head around even after a year+ of fooling with the ESP32. It’s still promising to see the price point and know that the development/support won’t be half baked.

FWIW - this Adafruit/LadyAda video has a really good introduction to what the new chip can do with regards to PIO

Not normally a fan of Raspberries Pi, but I like this one. The PIO stuff looks interesting. I hope they do something interesting with the dual core aspect. I’m not a huge Python person, but Micropython is great.

I think it’s cool that they’re making demos using the PIO to do video and other fun things. I think there’s a lot of potential uses in audio/synthesis, too. Might have to pick up one of these.

Maybe of interest to those considering the chip:

This Is Not Rocket Science posted this video which uses the new chippo today, which let them add polyphony to a longer term synthesizer project.


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I’m doing some back of the envelope math on using a pico with an optical mouse as an optical encoder. So an arc-like knob with a mouse eye looking at the bottom of it.

The pico would capture the output of the mouse (still not sure if ps2 or usb mice would be better) and output i2c for a host/parent device that would be doing the rest of the logic.

It feels like a stupid idea but it also seems oddly reasonable because of how cheep the pico and mice are.

You will find PS/2 serial is way easier than USB (usb host) particularly as you will want to present a USB device interface to your PC/Norns.

Personally I’d go with a quadrature encoder I was literally just reading an post on possibly reading quad enc using the PIO blocks.

To me the encoder is the easy bit and the hard parts of building an arc are the “display” and emulating the arc. Anyone happen to know how to drill a hole in an oled display? :grin:

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The “cheap” quadrature encoders I saw were like 30ish dollars but I could find mice like this one for 10.

the PIO blocks do seem like they would be able to help for quadrature.

I was wondering about putting a hole in an oled too! Punch hole cameras do it right? Another thought is a pico projector but that might have latency issues, and the other thought is just to have displays next too the knobs.

No official announcement yet but I managed to grab one of these boards from the Arduino store already :smiley:

Wifi, bluetooth, step-down converter (super wide input range !), gyroscope, accelerometer, rgb LED, and even a microphone, 16MB Flash and of course the dual core RP2040. It’s gonna be awesome :hugs: 🧑‍💻

And the news Arduino docs website looks awesome too:


Only just found this EuroPi project:

Note that the production model improves upon the one featured in the video:

When I found it, one of my first thoughts was that it could go nicely with an ORCA module, given that I2C is likely enough to be explored in either project.


Update: built my first thing just with a Pico soldered to the back of it. I’m using the castellated edges for most of that, although I also have three of the test pads on the back broken out: the BOOTSEL pad, and the two USB pads, so I can use a sturdier USB connector. (USB-C, which is working just fine as a 2.0 device using a pair of resistors, as @tehn points out).


Worked like a charm. I’m really enjoying the GCC/CMakeList tooling for this, too.

Although: I’d seriously consider using a bare RP2040, now that my cheap assembly house have them in stock. They’re about a dollar, and you need very little else to get them running (as the Pico suggests)… but you can a lot of flexibility of layout.


Almost the same here. Pico soldered directly to a PCB.
Before putting the project in stand-by, I was mainly using the Arduino IDE (Mbed core or Earl Philower core). I’ll try to use the full SDK and its toolchain when I get back to it.
Also, I need to wrap my head around the PIO system… Not for crazy things, maybe just for dealing with a rotary encoder… That kind of stuff…


The creator of this project opened a topic right here a couple of weeks ago, only to delete it after I suggested some modifications, as it lacked basic protections on the IOs… :thinking:


The GCC toolchain is nice to get running, because their first-class dev platform is a Raspberry Pi - meaning they presuppose unix and the command line, rather than anything more sophisticated (Windows, Eclipse). Drop me a line if you run into issues - once it’s up and running, I’ve got VSCode happily spitting out UF2 files with a single click, and the integrations are excellent.

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So what’s the expected risk of that, then? It would just endanger the Pico itself to accidentally plug a higher voltage euro output into the EuroPi’s outputs, correct?

A schematic is available on github :


The creator considered the digital pins would only be outputs, and didn’t even used current limiting resistors on the LEDs. You’ll notice these are directly connected to the sockets.

I suggested that, as it is programmable and to be used in a modular context, people would inevitably want to use digital pins as inputs at some point, and you can’t just expect them to use 3.3V (and unipolar!) signals only, within a Eurorack system.

Let’s say you really only use these as outputs, one can always make an output to output connection by mistake, so it would have been good to have protection for that case. People simply always find creative ways to break things.

The pico is indeed cheap, yet it’s not a reason to take the chance to fry these. He wanted to keep it cheap, yet once you replaced a pico, you already burned the money it would have taken to add some protections, and depending on how basic you go, you may still have some money left.

Another thing is the 3.3V max output levels, that can be an issue when you see that some modules (fortunately less and less) have trouble triggering from 5V signals already… You can also often see some users complaining about modules not being able to go up to 8V, so the PWM outs based on a 3.3V signal would also be very limiting.

I already had (and still have!) a similar module idea before I saw this, yet I didn’t find what would be the right UI or scenario yet to take full advantage of the RP2040 capabilities.

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Yeah, eesh. It’s pennies to stick resistors on those LEDs, and a few more pennies for some diode-pairs on the out/ins (if you really are going to clamp to 3.3V as a maximum). It really is the minimal viable approach to using it.