Raspberry Pi Pico#

Warning

This target is in an early state and is under active development. Usability is not very polished, and many features/configuration options that work in upstream Pi Pico CMake build have not yet been ported to the GN build.

Setup#

To use this target, Pigweed must be set up to build against the Raspberry Pi Pico SDK. This can be downloaded via pw package, and then the build must be manually configured to point to the location of the downloaded SDK.

pw package install pico_sdk

gn args out
  # Add this line.
  PICO_SRC_DIR = getenv("PW_PACKAGE_ROOT") + "/pico_sdk"

Usage#

The Pi Pico is currently configured to output logs and test results over UART via GPIO 1 and 2 (TX and RX, respectively) at a baud rate of 115200. Because of this, you’ll need a USB TTL adapter to communicate with the Pi Pico.

Once the pico SDK is configured, the Pi Pico will build as part of the default GN build:

ninja -C out

Pigweed’s build will produce ELF and UF2 files for each unit test built for the Pi Pico.

Flashing#

Flashing the Pi Pico is two easy steps:

  1. While holding the button on the Pi Pico, connect the Pico to your computer via the micro USB port.

  2. Copy the desired UF2 firmware image to the RPI-RP2 volume that enumerated when you connected the Pico.