Seeeduino Xiao RP2040

The ​Seeeduino Xiao RP2040 brings extra capacity while keeping the same compact size of the Xiao M0+. It is based on the dual-core Raspberry Pi RP2040 with 256 kB of RAM and 2 MB of Flash.

The USB connector is a Type-C, which takes almost one third of the board.

The board was sampled by Seeeduino. 

Hardware

The board has a DIP14 700 mil form-factor, plus castellated pins.

The board features 14 pins with all the standard ports, including two UART ports (one for USB, another on dedicated pins), I²C and SPI.

The board comes with two push buttons, one for RESET and another for BOOT. This is especially handy for rebooting the RP2040 as a mass storage device.

Also included, a neopixel RGB LED and three LEDs, although with inverted logic.
Click to enlarge
On the front side (left), close to the USB connector, a red LED for power and three RGB LEDs, although in negative logic. On the opposite, two buttons for BOOT and RESET, and a neopixel. 

On the rear side (right), the Xiao board exposes pads for SWD clock and data signals, making debugging possible, as well as RESET and GND.

Software

There are at least two different boards packages for the Xiao RP2040.
  • The official package is provided by Seeed, and it comes in various releases. I wasn't able to get the latest version 2.7.2 working. Downgrading to release 1.12.0 solved the issue.
Surpinsingly, the code of the boards packages is not available as an open source from a GitHub repository. It is actually downloaded from files.seeedstudio.com. More confusingly, latest release 2.7.2 relies on the Arduino port based on mbedOS, while previous release 1.12.0 is based on the Raspberry Pi SDK by Earle F. Philhower.
  • I strongly recommend the excellent arduino-pico port by Earle F. Philhower.
The port is open source and available on GitHub. It provides clear names for the GPIOs, as well as for the neopixel and the RGB LEDs.
​
Not all boards packages are equal
On the documentation side, Seeed provides the usual wiki page but it doesn't list the GPIOs used for the RGB LEDs and neopixel. ​As a matter of facts, the D0..D10 naming scheme proved to be confusing. Using the GPIO numbers was easier.

Conclusion

After the excellent surprise with the Xiao M0+, I was expecting a lot from the Xiao RP2040.

​Alas, apart from its compact form-factor, it is both more expensive than the original Raspberry Pi Pico RP2040 board and less versatile due to its limited number of pins. The USB-C cable is not included. Actually, it is almost as large and expensive as the board.

The major limitation comes from the rather confusing official software and documentation. And the official software doesn't even come as an open source GitHub repository. Better to use the excellent port by Earle F. Philhower.

However, the Xiao RP2040 would fit into highly compact projects, like the Driving a Large E-Paper Display with a Compact Xiao RP2040.

Pros

  • Powerful and compact board
  • Castellated pins for easy integration
  • Exposed SWD pads for debugging

Cons

  • Confusing official software and documentation
  • No GitHub repository

Wrap-Up

  • Recommended for highly compact project
  • USB-C cable as large and expensive as the board

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