“I’m interested in designing an expansion card and have a few ideas, but I’d love to hear more suggestions. I really liked this project: Dual RP2040 Dev Board and Debugger and was thinking of creating something similar using the new RP2350. A bit about me—I’m 16, based in the UK, and currently studying Electrical and Electronic Engineering at the T Level. Excited to learn and collaborate!”
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Oh, a RP2350 card would be great! Do you have ideas on what to do with it?
For a quick prototype without making a custom PCB, you could just stick one of the small RP2350 boards which are now available into a case, plus a plug held into position & wired up.
There is the “RP2350 Tiny” board size 18mm * 23.5mm * 2.1mm they say. USB pins, reset and boot lines on a 8pin 0.5mm pitch FFC connector. Plus a USB-C & button daughterboard. $5 shipped direct-from-china: aliexpress.us/item/3256808131385368.html.
And the “RP2350 MINI” board size 21mm * 25.5mm (plus port length). USB pins available at large solder pads on the bottom. Plus onboard USB-C & buttons. $5 aliexpress.us/item/3256808153403052.html
Both should fit github.com/FrameworkComputer/ExpansionCards/tree/main/Mechanical. And Iirc there can be a bit more space available than shown there. Though the “RP2350 Tiny” would have the need either an FFC breakout board or a custom USB-C male to FFC board. Whereas the “RP2350 MINI” though it might be a larger board, with it’s USB solder pads it could just be wired right to one of the little USB-C male boards that are sold. Which could probably even be hot-glued in place for that fun extra quick & dirty look!
Welcome to the forum btw.
It’s a shame that a vulnerability was found in the OTP memory breaking the root of trust & compromising it’s use for things like security keys. (picokeys.com/pico-fido) Though depending on your threat model I’d still be tempted to play with it for use with lower security / risk situations, and just epoxy the f*ck out of the board to make access to the needed pin a royal pain in the ass & not really worth it for the value of what it’s being used to protect. Maybe Raspberry Pi will eventually introduce a chip revision to fix it. tomshardware.com/raspberry-pi/it-looks-like-the-raspberry-pi-rp2350-hacking-challenge-has-been-beaten-hacker-gains-access-to-the-otp-secret-by-glitching-the-risc-v-cores-to-enable-debugging
Oh, and I see they made a RP2350 version of the extremely tiny “Core-A” board. 20.32 * 17. 78 * 3mm. $6 aliexpress.us/item/3256808319537520.html
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Other designs I have seen stick within the topical port size and leave some gpio ports unused on other solution Is to have a larger module like the ethernet port with to use all of the gpio pins of the 2 rp2350 around 40 after adding the connections however this brings about the issue of transportation. I have started designing the schematic using the KICAD template from framework only thing is I don’t have a framework laptop but I can still test it if I make it based on cad models provided and also just using the usb port and using a bi directional usb to usb c cable
If you wanted a rp2350 expansion port how many rp2350 would you want in it?
- 1
- 2
- 3
0
voters
How many gpio pins would you want?
- 10 (1 rp2350)
- 10 (2 rp2350)
- 20 (1)
- 20 (2)
- 30 (2)
- 40 (2)
0
voters
Specifically I am using the rp2350B
How many pins would I want? Well, however many ya can fit! 
Since there always seems to be some use that needs more than you have.
But if it requires carrying some adapter to actually plug your usual things in, are you really saving anything? What type of connectors were you looking at? A dual 2.54mm header would max out at 20 pins, I think. Not sure the vertical space, if you could stuff in 2 dual 20p headers. A 1.27mm header certainly fits a lot more but that less common for hobbyists.
How far would you say should it stick out the ethernet port kind of distance to gain vertical height or have it extend out more.
Also what are your thoughts on connectors such as qwiuc connect. If I have more than one chip how do I code to them individually despite using the same usb port.
