Adafruit 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 |
| USBDevice | YES | YES |
Pins
| Pin | Hardware pin | Alternative names | PWM |
|---|---|---|---|
D0 |
PB09 |
A6, UART_RX_PIN |
|
D1 |
PB08 |
A7, UART_TX_PIN |
|
D2 |
PB02 |
A5, SDA_PIN |
|
D3 |
PB03 |
A4, SCL_PIN |
|
D4 |
PA28 |
BUTTONA, BUTTON |
|
D5 |
PA14 |
BUTTONB, BUTTON1 |
TCC0 (channel 0) |
D6 |
PA05 |
A1 |
TCC0 (channel 1) |
D7 |
PA15 |
SLIDER |
TCC0 (channel 1) |
D8 |
PB23 |
NEOPIXELS, WS2812 |
|
D9 |
PA06 |
A2 |
TCC1 (channel 0) |
D10 |
PA07 |
A3 |
TCC1 (channel 1) |
D12 |
PA02 |
A0 |
|
D13 |
PA17 |
LED |
TCC2 (channel 1), TCC0 (channel 3) |
A8 |
PA11 |
LIGHTSENSOR |
TCC1 (channel 1), TCC0 (channel 3) |
A9 |
PA09 |
TEMPSENSOR |
TCC0 (channel 1), TCC1 (channel 3) |
A10 |
PA04 |
PROXIMITY |
TCC0 (channel 0) |
USBCDC_DM_PIN |
PA24 |
TCC1 (channel 2) |
|
USBCDC_DP_PIN |
PA25 |
TCC1 (channel 3) |
|
SDA1_PIN |
PA00 |
TCC2 (channel 0) |
|
SCL1_PIN |
PA01 |
TCC2 (channel 1) |
|
SPI0_SCK_PIN |
PA21 |
TCC0 (channel 3) |
|
SPI0_SDO_PIN |
PA20 |
TCC0 (channel 2) |
|
SPI0_SDI_PIN |
PA16 |
TCC2 (channel 0), TCC0 (channel 2) |
|
I2S_SCK_PIN |
PA10 |
TCC1 (channel 0), TCC0 (channel 2) |
|
I2S_SD_PIN |
PA08 |
TCC0 (channel 0), TCC1 (channel 2) |
Machine Package Docs
Documentation for the machine package for the Circuit Playground Express
Flashing
UF2
The Circuit Playground Express comes with the UF2 bootloader already installed.
CLI Flashing
-
Plug your Circuit Playground Express into your computer’s USB port.
-
Flash your TinyGo program to the board using this command:
tinygo flash -target=circuitplay-express [PATH TO YOUR PROGRAM] -
The Circuit Playground Express board should restart and then begin running your program.
Troubleshooting
If you have troubles getting your Circuit Playground Express board to receive code, try this:
-
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.
-
Now try running the command:
tinygo flash -target=circuitplay-express [PATH TO YOUR PROGRAM]
Once you have updated your Circuit Playground Express board the first time, after that you should be able to flash it entirely from the command line.
Notes
You can use the USB port to the Circuit Playground Express as a serial port. UART0 refers to this connection.
The Neopixel LED on the Circuit Playground Express can be accessed using the WS2812 driver via the PB23 pin.
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/release/examples