Raspberry Pi Pico

The Raspberry Pi Pico features the RP2040 — a dual-core ARM Cortex-M0+ with generous RAM and the unique PIO (Programmable I/O) subsystem. Good for projects needing precise timing or multiple serial buses.

Specs

Firmware setup

PlatformIO

; platformio.ini
[env:pico]
platform = raspberrypi
board = pico
framework = arduino
lib_deps = conduyt

pio run --target upload

Arduino IDE

1. Go to Tools → Board → Boards Manager
2. Search for pico and install Raspberry Pi Pico/RP2040
3. Select Raspberry Pi Pico from the board list
4. Select the serial port from Tools → Port

Transport

USB serial:

#include <Conduyt.h>

ConduytSerial  transport(Serial, 115200);
ConduytDevice  device("PicoDevice", "1.0.0", transport);

void setup() {
  Serial.begin(115200);
  device.begin();
}

void loop() {
  device.poll();
}

Browser flashing

1. Unplug the Pico from USB
2. Hold the BOOTSEL button (small white button on the board)
3. While holding BOOTSEL, plug the USB cable into the Pico
4. Release BOOTSEL — the Pico appears as a USB mass storage device (like a flash drive) named RPI-RP2
5. Go to the Playground, click Flash, select Raspberry Pi Pico

If the Pico doesn't appear as a drive, make sure you're holding BOOTSEL before plugging in, not after.

Built-in LED

Pin 25 (directly wired, no PWM support on this pin).

On the Pico W, the LED is connected through the WiFi chip. Use LED_BUILTIN instead of a pin number:

pinMode(LED_BUILTIN, OUTPUT);
digitalWrite(LED_BUILTIN, HIGH);

Common issues

• No serial port appearing: The Pico's USB serial only appears after firmware that calls Serial.begin() is running. If you have a blank Pico, flash via BOOTSEL mode first.
• Upload fails in Arduino IDE: Hold BOOTSEL, plug in the board, release BOOTSEL, then click Upload. Some IDE versions auto-detect BOOTSEL mode.
• Only 3 analog pins: The RP2040 has ADC on GP26, GP27, and GP28 only. Other pins don't support mode('analog').