tinygo/targets/circuitplay-express.json

{
    "inherits": ["atsamd21g18a"],
    "build-tags": ["circuitplay_express"],
    "flash-1200-bps-reset": "true",
    "flash-method": "msd",
    "serial-port": ["239a:8018"],
    "msd-volume-name": ["CPLAYBOOT"],
    "msd-firmware-name": "firmware.uf2"
}