Circuit Playground Express

The Adafruit Circuit Playground Express is small ARM development board based on the Atmel SAMD21 family of processors. It has several built-in devices such as WS2812 “NeoPixel” LEDs, buttons, an accelerometer, and some other sensors.

Interfaces

Interface Hardware Supported TinyGo Support
GPIO YES YES
UART YES YES
SPI YES YES
I2C YES YES
ADC YES YES
PWM YES YES

Flashing

UF2

The Circuit Playground Express comes with the UF2 bootloader already installed.

  • Plug your Circuit Playground Express into your computer’s USB port.
  • Press the “RESET” button on the board two times to get the Circuit Playground Express board ready to receive code.
  • The Circuit Playground Express board will appear to your computer like a USB drive. Determine the path to the board, for example on Linux it will be something like /media/[USERNAME]/[NAME OF THE BOARD].
  • Build your TinyGo program to the board in .uf2 format using the tinygo build -o=/media/[USERNAME]/[NAME OF THE BOARD]/flash.uf2 -target=circuitplay-express [PATH TO YOUR PROGRAM] command.
  • The Circuit Playground Express board should restart and then begin running your program.

Notes

You can use the USB port to the Circuit Playground Express as a serial port. UART0 refers to this connection.

For an example that uses the built-in Neopixel LEDs, take a look at the TinyGo drivers repository located at https://github.com/tinygo-org/drivers/tree/master/examples