Adafruit Feather M4 Express Manual page 93

Create a new simple Blink sketch example:
// the setup function runs once when you press reset or power the board
void setup() {
// initialize digital pin 13 as an output.
pinMode(13, OUTPUT);
}
// the loop function runs over and over again forever
void loop() {
digitalWrite(13, HIGH);
delay(1000);
digitalWrite(13, LOW);
delay(1000);
}
Make sure the LED(s) are still green, then click Upload to upload Blink. Once it has uploaded successfully, the serial
Port will change so re-select the new Port!
Once Blink is uploaded you should no longer need to double-click to enter bootloader mode, Arduino will automatically
reset when you upload
© Adafruit Industries
// turn the LED on (HIGH is the voltage level)
// wait for a second
// turn the LED off by making the voltage LOW
// wait for a second
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