In the electronics world, a little one-inch square board with castellated edges allows a lot of circuitry to be easily added in a small surface area. You can grab a prepopulated module, throw it onto your PCB of choice, and save yourself a lot of time routing and soldering. This tiny Raspberry Pi 2040 module from [SolderParty] ticks all those boxes.

With all 30 GPIO broken out, 8MB of onboard flash, and a NeoPixel onboard, you have plenty to play with on top of the already impressive specs of the RPi2040. Gone are the days of in-circuit programmers, and it uses a UF2 bootloader to make it easy B to transfer new images over USB. Rust, MicroPython, Arduino, and the PicoSDK are all development options for code. All the KiCad files, BOM, schematics, and firmware are up on GitHub under a CERN license for your perusal pleasure. They’ve helpfully included footprints as well as a reference carrier board design.

It is a handy little project that might be good to keep in mind or just use as a reference design for your efforts. We have a good overview of the RPi2040 from an STM perspective. If you’re curious about what you could even use this little stamp for, why not driving an HDMI signal?

5 thoughts on “Putting The RP2040 On A Stamp”

1. Mike Massen, Perth, Western Australia says:
   March 28, 2022 at 1:48 am

   Nice post, great to see more integration & accessibility ie bigger than SOT connections, eek. I’ve often used silabs parts for various embedded after moving up from Atmel’s 4051 & Motorola 68hc705 series, often felt if I went to an OS & higher level languages I’d feel losing out in controls & efficiency, style I guess as I seem to still think in z80 assembler with a built in translator for most other assemblers. Bit quirky as I used to teach pedal, Fortran in mid 1980’s

   So I’m curious how people go across the raspberry series for coding in assembler for embedded tight minimal overheads as in no OS (although later out etc is ok) only essential libraries for wifi, Lan and other higher level partially proprietary libraries etc hopefully re-entrant not interfering with timing of my code etc

   IOW. Like to cut my teeth on a suitable low end raspberry or equivalent/compatible platform gaining assembler experience then exploring incrementally more advanced to SOC types. Would love to do this on a windows 7 laptop or even an android tablet.

   Could I use the device described here with an off the shelf assembler or even an Integrated Development Environment, maybe something like silabs studio series etc ?

   I’m specifically interested in instrumentation logging, some Fourier and also tight timing controls of arrays of power delivery for diverse electro chem experiments, though occasional minor toy design has developed a minor interest…

   Thanks for the article :-)

   Reply
   1. David Given says:
      March 28, 2022 at 2:28 am

      The PicoSDK is built around C, but you can of course drop in as much assembly as you like — it’s all gcc and cmake based so .S files should Just Work. I’d probably suggest using C on one core for the non timing-critical stuff and your custom assembly running on the other core for the bare metal stuff, communicating via mailboxes. Talking to hardware is mostly intended to be done by the C interfaces; they’re really nice, with overhead-free type-safe wrappers around all the hardware functionality. There _are_ some headers for use with assembly but I don’t think they’re the primary focus. But the hardware is well-documented so using it from assembly wouldn’t be difficult.

      The architecture is Thumb2, which is really easy to work with. So easy it’s incredibly dull, in fact.

      When I did the Fuzix port I ended up with exactly one assembler file (for the context switching). Everything else was in C.

      Reply
      1. Mike Massen, Perth, Western Australia says:
         March 28, 2022 at 2:47 am

         Cool, thanks :-)
         So long since I’ve done any C let alone C++ which I developed an aversion too. So I could use Win 7 fine for time being then :-). I still have an oldie Dell 1545 Inspiron, few minor repairs trimmed Win 7 professional, a breeze really quick been bloat free for ages, quite responsive though did upgrade to SSD, faster CPU & ram to max 8G bytes, yikes.
         When I was at W.A.I.T. back then (renamed to Curtin University) also taught Basic and dabbled in KL-10 assembler, loved the intriguing sharable high segment structure and address modes, that was a “super computer” of 1975 era, 256 K words 36 bit, handled 100 users all doing Basic, worked fine minimal delay – hacked a few times by 1st yr eng students hrrm, CPU cycle time around a micro sec, lots of registers as part of OS swap space etc

         Still have few micro development kits from early 2000’s and heaps of CROs, HP DSOs etc even an A0 roll feed plotter HP 7586B, which I hope to use soon to craft large sheets or rolls of supercap like materials for a power harvesting experiment…

         Btw typos in my post:-
         *Pascal – not pedal
         *paged out – not later out

         Reply
2. Laurence says:
   March 28, 2022 at 4:34 am

   This piece of news hides another interesting fact: this board is sold on lectronz.com, a platform that seems to position itself as a new modern alternative to Tindie…

   I’m a bit sceptical whether this new platform will find success in a shrinking market suffering from big supply chain issues, but It’s great to see new alternatives for the community!

   Reply

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