I’ve used these boards a bit - not a ton, but enough to get something simple running.

The smallest reasonable platformio.ini to try would be:

[env:avr_ble]
platform = atmelmegaavr
board = ATmega3208
framework = arduino
monitor_speed = 115200

For a basic “hello world” blink, the board has two user LEDs: - green “Data” LED -> PF4 - red “Error” LED -> PF5

According to the user guide they’re active-low, so you turn them on by writing LOW (pulling the pin to ground).

Since it's a Microchip board and not a typical Arduino board, I wouldn’t assume something like LED_BUILTIN will work - it’s safer to just hit the registers directly at first:

#include <Arduino.h>

void setup() {
  // PF4 = green Data LED
  PORTF.DIRSET = PIN4_bm;
}

void loop() {
  // active-low LED
  PORTF.OUTCLR = PIN4_bm;  // LED on
  delay(500);
  PORTF.OUTSET = PIN4_bm;  // LED off
  delay(500);
}

That avoids guessing how (or if) the Arduino core mapped the pins.

PlatformIO does support the ATmega3208 so building should work fine, but it doesn’t support uploading/debugging for it, and Microchip’s docs specifically mention using MPLAB X/Microchip Studio with the onboard debugger.

But, to flash manually: - build with PlatformIO in VS Code - grab the .hex from .pio/build/avr_ble/ - flash it via USB (the board supports drag and drop programming so you can literally just drop the .hex onto the drive like it's a flash drive)

I’ve used these boards a bit - not a ton, but enough to get something simple running.

The smallest reasonable platformio.ini to try would be:

[env:avr_ble]
platform = atmelmegaavr
board = ATmega3208
framework = arduino
monitor_speed = 115200

For a basic “hello world” blink, the board has two user LEDs: - green “Data” LED -> PF4 - red “Error” LED -> PF5

According to the user guide they’re active-low, so you turn them on by writing LOW (pulling the pin to ground).

Since it's a Microchip board and not a typical Arduino board, I wouldn’t assume something like LED_BUILTIN will work - it’s safer to just hit the registers directly at first:

#include <Arduino.h>

void setup() {
  // PF4 = green Data LED
  PORTF.DIRSET = PIN4_bm;
}

void loop() {
  // active-low LED
  PORTF.OUTCLR = PIN4_bm;  // LED on
  delay(500);
  PORTF.OUTSET = PIN4_bm;  // LED off
  delay(500);
}

That avoids guessing how (or if) the Arduino core mapped the pins.

PlatformIO does support the ATmega3208 so building should work fine, but it doesn’t support uploading/debugging for it, and Microchip’s docs specifically mention using MPLAB X/Microchip Studio with the onboard debugger.

But, you can flash manually: - build with PlatformIO in VS Code - grab the .hex from .pio/build/avr_ble/ - flash it via USB (the board supports drag and drop programming so you can literally just drop the .hex onto the drive like it's a flash drive)

See more docs here.