The Latest Board From Solder Party Gets Our Stamp of Approval!

There is a lot to be said about the SoM-style form factor when it comes to module offerings in the embedded processing market.

Often aimed at lowering the barrier to entry for prototypes or MVP-level products, it is surprising to see just how densely packed such modules can be!

With such examples as the RPi CM4 compute module at one end of the complexity spectrum, and simpler designs such as the SAM D51-powered, Circuit Python-compatible CircuitBrains module from Kevin Neubauer sat closer to the other end of the scale, there are a huge range of form factor types, connector methods and levels of integration to choose from in this market.

While many hobbyist-level designers might not be dropping something like a CM4 in every project, many would likely drop in the CM4's baby cousin, the recent new silicon from the Pi Foundation, the RP2040 MCU — as showcased by the Raspberry Pi Pico development board and the plethora of projects that we have seen pour from the power packed into this processor.

The RP2040 is a beast, as is capably demonstrated by one of @arturo182's other recent boards — the Zero RP2040, which crams the new chip onto a board that allows it to maintain the 40-pin Raspberry Pi "standard" I/O header.

By cleverly mapping the I/O of the RP2040 to faithfully replicate the signals found on the old IDC header, users of the RP2040 Zero are enabled to interact with, and capably drive the myriad of hats and bonnets that were once designed to be bolted onto the older Broadcom-based boards.

With the power of the RP2040 clearly displayed in the GIF above, you can see why arturo182 may have been inspired to par down the physical size of the circuit that supports the RP2040 in his designs, to see just how small a Pi Pico PCB contender can reasonably be!

Packing a punch into a postage stamp!

With the one-inch square PCB design competition over at Hackaday often turning up some very interesting results, this postage-stamp-sized module would be a worthy contender — with an impressive litany of features crammed into this RP2040 circuit board module.

First and foremost, let's talk about the brains that this module boasts!

The RP2040 is a beast of a processor featuring two Cortex-M0+ cores, nominally running at 133MHz (but overclockable to 400MHz!), 264 KB SRAM, the usual peripherals (SPI, I2C, PWM, UARTs, DMA and USB 1.1 Device and Host Controller modes), along with the incredibly nifty eight-channel PIO state machine I/O controller, we've seen it flexing it's might in a range of projects — from synchronously driving parallel strings of WS2812 LEDs, to the very impressive PicoDVI project by Luke Wren seen below.

Yup, that's a MCU driving dual DVI displays — thanks to the Programable I/O of the RP2040. Incredible!

Speaking of PIO, we should probably also take a look at the I/O capabilities of the stamp SoM...

With all 30 of the available GPIO pins of the RP2040 (including the 4 ADC capable channels) broken out to three of the four 10-pin, 2.00mm pitch castellated edge connectors located around the edges of the SoM, any project that was previously possible with the Raspberry Pi Pico board will be possible with the RP2040 stamp module! Great!

The remaining 10-poisition header is made up of power pins, the USBBOOT, !RESET, SWCLK, SWDIO and USB D+ / D- pins, all neatly on one side of the SoM — which should ease integration into any host PCB design.

Despite there not being much of a crossover between many of the users running Circuit Python and those looking to target the RP2040 over the SWD interface, it's awesome to see these signals bought out, for those looking to tinker with the Cortex-M0+ cores on a lower level.

You just know there's going to be a NeoPixel hiding about on here somewhere...

Nestled in next to the RP2040 itself sits a WS2812-2020 format NeoPixel, allowing for quick and easy feedback from the bootloader — and application itself!

Mega amounts of FLASH!

The RP2040 Stamp boasts a beefy 16MB FL:ASH memory IC, which serves as storage for the user application, and is also able to serve as storage for a small amount of embedded resource, which can come in very handy at times!

Li-Po-a-go-go!

A pint-sized processing core screams out for being packed into portable applications - and what better way to support such use cases than to take the extra step to include an on-board Lithium-Ion chemistry cell charger IC, which safely manages the required tickling needed to trickle charge those otherwise, potentially... toasty cell types.

Reassuringly, there's a RESET button on this board!

With enough frustrations voiced by the community at the lack of a reset button on the Pi Pico PCB, arturo182 was certain to make sure this RP2040 board proudly boasted the push-to-reset functionality that so many CircuitPython users rely upon, in order to access the bootloader.

Bootstrap your stamp-based design with a baseboard reference!

Before arturo182 has barely burned and booted the CircuitPython bootloader, he's already off on the next project - a carrier board reference design, that serves to break out the castellated edge connectors around the sides of the RP2040 Stamp SoM, and send them out to some more familiar looking headers - those of the Arduino R3 form factor layout.

As the Zero RP2040 served to allow users to easily prototype with the RP2040 MCU, and their existing supply of Raspberry Pi form factor based peripheral boards — this carrier will likewise enable Arduino users to focus first-and-foremost on their code, with hardware compatibility handily taken care by this carrier board, during the prototyping stages of their next RP2040-based project!

Get a solid footing on your next RP2040 project with a EDA support from Solder Party!

Going one step above and beyond, as is usual with the level of work from @arturo182, we also see that he has been so kind as to furnish us with footprint files and schematic symbols for either EAGLE or KiCAD users.

Although some might say that only two supported file types is a bit of a stumbling block — I say that's a fair compromise, seeing as most other EDA packages will nowadays be able to import one format, if not the other!

While we keenly await the release of production proven source files, we suggest that those interested in seeking out additional information on the RP2040 stamp should saunter over to Twitter, where @arturo182 is sure to update in real-time with developments surrounding this miniature module as they happen!