BinKey

seeed-xiao-rp2040

6 min read

Important Note

This entire repo was AI created - including all of the data within. The intent was to A) help me with my personal electronics inventory; and B) see how I could use AI to make that process a bit easier. DO NOT TRUST!

Seeed Studio XIAO RP2040

Details

  • Location: Cabinet-1, Bin 32
  • Category: Microcontroller Boards
  • Type: RP2040 Development Board (XIAO Form Factor)
  • Microcontroller: RP2040 (Dual ARM Cortex-M0+ @ 133MHz)
  • Brand: Seeed Studio
  • Part Number: 102010428
  • Quantity: 1
  • Product URL: https://wiki.seeedstudio.com/XIAO-RP2040/

Description

The Seeed Studio XIAO RP2040 is as small as the Seeed Studio XIAO SAMD21 but more powerful. It carries the powerful dual-core RP2040 processor with flexible clock running up to 133 MHz. Despite its tiny thumb-sized form factor (21x17.8mm), it packs 264KB of SRAM and 2MB of on-board Flash memory, making it perfect for wearable devices and small projects.

Specifications

  • Microcontroller: Dual-core ARM Cortex M0+ processor up to 133MHz
  • Logic/Power: 3.3V (5V tolerant via VIN pin)
  • Memory: 264KB SRAM, 2MB Flash memory
  • GPIO Pins: 14 total (11 digital, 4 analog)
  • ADC: 4x 12-bit ADC channels
  • Peripherals: 1x I2C, 1x SPI, 1x UART, 1x SWD
  • PWM: 11 PWM pins
  • USB: USB Type C connector with native USB support
  • Special Features: Built-in RGB LED, Boot/Reset buttons

Dimensions

  • Board Size: 21mm x 17.8mm x 3.5mm (0.8” x 0.7” x 0.1”)
  • Weight: ~3g
  • Form Factor: XIAO family compatible

Image

Seeed Studio XIAO RP2040

Features

  • Powerful dual-core RP2040 processor up to 133MHz
  • Rich on-chip resources with 264KB SRAM and 2MB Flash
  • Flexible compatibility: Arduino, CircuitPython, MicroPython
  • Breadboard-friendly & SMD design with no back components
  • Thumb-sized form factor perfect for wearables
  • Multiple interfaces: 11 digital pins, 4 analog pins, 11 PWM pins
  • Compatible with XIAO expansion boards
  • Built-in programmable RGB LED (reversed logic)
  • UF2 bootloader support for easy programming

Pinout Diagram

XIAO RP2040 Pinout

Basic Wiring Examples

XIAO Pin D0 → LED Anode (long leg)
LED Cathode (short leg) → 220Ω Resistor → XIAO GND

Note: Built-in RGB LED available (reversed logic - LOW = ON)

Button Input Circuit

XIAO 3V3 → 10kΩ Pull-up Resistor → XIAO Pin D1
XIAO Pin D1 → Button → XIAO GND

Code: digitalRead(D1) returns HIGH when not pressed, LOW when pressed

I2C Device Connection

I2C Device VCC → XIAO 3V3
I2C Device GND → XIAO GND
I2C Device SDA → XIAO Pin D4 (SDA)
I2C Device SCL → XIAO Pin D5 (SCL)

Note: Built-in pull-up resistors included

SPI Device Connection

SPI Device VCC → XIAO 3V3
SPI Device GND → XIAO GND
SPI Device SCK → XIAO Pin D8 (SCK)
SPI Device MOSI → XIAO Pin D10 (MOSI)
SPI Device MISO → XIAO Pin D9 (MISO)
SPI Device CS → XIAO Pin D7 (CS)

Analog Sensor Reading

Sensor Output → XIAO Pin A0, A1, A2, or A3
Sensor VCC → XIAO 3V3
Sensor GND → XIAO GND

Code: analogRead(A0) returns 0-65535 (0-3.3V)

UART Communication

Device TX → XIAO Pin D7 (RX)
Device RX → XIAO Pin D6 (TX)
Device VCC → XIAO 3V3
Device GND → XIAO GND

Code: Serial1.begin(9600) for UART communication

Programming Setup Guide

  1. Download CircuitPython UF2 from circuitpython.org
  2. Hold BOOT button while connecting USB-C
  3. Drag UF2 file to RPI-RP2 drive
  4. Board reboots as CIRCUITPY drive
  5. Edit code.py to program

Arduino IDE Setup

  1. Install Arduino IDE 2.0+
  2. Add RP2040 board package URL in preferences
  3. Install “Raspberry Pi Pico/RP2040” boards
  4. Select “Seeed XIAO RP2040” from Tools → Board
  5. Hold BOOT while connecting for first upload

MicroPython Setup

  1. Download MicroPython UF2 from micropython.org
  2. Hold BOOT button while connecting USB-C
  3. Drag UF2 file to RPI-RP2 drive
  4. Use Thonny IDE or terminal for programming

Programming Examples

CircuitPython RGB LED Example

import board
import digitalio
import time
 
# RGB LED pins (reversed logic - LOW = ON)
led_r = digitalio.DigitalInOut(board.LED_RED)
led_g = digitalio.DigitalInOut(board.LED_GREEN)
led_b = digitalio.DigitalInOut(board.LED_BLUE)
 
led_r.direction = digitalio.Direction.OUTPUT
led_g.direction = digitalio.Direction.OUTPUT
led_b.direction = digitalio.Direction.OUTPUT
 
while True:
    # Red
    led_r.value = False  # ON
    led_g.value = True   # OFF
    led_b.value = True   # OFF
    time.sleep(1)
 
    # Green
    led_r.value = True   # OFF
    led_g.value = False  # ON
    led_b.value = True   # OFF
    time.sleep(1)
 
    # Blue
    led_r.value = True   # OFF
    led_g.value = True   # OFF
    led_b.value = False  # ON
    time.sleep(1)

Arduino RGB LED Example

#define LED_RED 17
#define LED_GREEN 16
#define LED_BLUE 25
 
void setup() {
  pinMode(LED_RED, OUTPUT);
  pinMode(LED_GREEN, OUTPUT);
  pinMode(LED_BLUE, OUTPUT);
 
  // Turn off all LEDs (HIGH = OFF for XIAO)
  digitalWrite(LED_RED, HIGH);
  digitalWrite(LED_GREEN, HIGH);
  digitalWrite(LED_BLUE, HIGH);
}
 
void loop() {
  // Red
  digitalWrite(LED_RED, LOW);   // ON
  digitalWrite(LED_GREEN, HIGH); // OFF
  digitalWrite(LED_BLUE, HIGH);  // OFF
  delay(1000);
 
  // Green
  digitalWrite(LED_RED, HIGH);   // OFF
  digitalWrite(LED_GREEN, LOW);  // ON
  digitalWrite(LED_BLUE, HIGH);  // OFF
  delay(1000);
 
  // Blue
  digitalWrite(LED_RED, HIGH);   // OFF
  digitalWrite(LED_GREEN, HIGH); // OFF
  digitalWrite(LED_BLUE, LOW);   // ON
  delay(1000);
}

CircuitPython I2C Scanner

import board
import busio
 
i2c = busio.I2C(board.SCL, board.SDA)
 
while not i2c.try_lock():
    pass
 
print("I2C addresses found:", [hex(device_address)
      for device_address in i2c.scan()])
 
i2c.unlock()

Arduino Analog Reading

void setup() {
  Serial.begin(115200);
  while (!Serial);
  Serial.println("XIAO RP2040 Analog Reading");
}
 
void loop() {
  // Read all 4 analog pins
  for (int i = 0; i < 4; i++) {
    int analogValue = analogRead(A0 + i);
    float voltage = analogValue * (3.3 / 65535.0);
 
    Serial.print("A");
    Serial.print(i);
    Serial.print(": ");
    Serial.print(analogValue);
    Serial.print(" (");
    Serial.print(voltage, 2);
    Serial.print("V)  ");
  }
  Serial.println();
  delay(1000);
}

Important Notes

Power Considerations

  • 3.3V Logic: All GPIO pins are 3.3V logic level
  • USB-C Power: Can be powered via USB-C or 3V3/5V pins
  • Current Limit: 600mA peak from onboard regulator
  • Battery Power: Supports battery power (disconnect USB when using battery)

Pin Limitations and Features

  • ADC Pins: A0, A1, A2, A3 can be used for analog input (12-bit)
  • PWM: 11 pins support PWM output
  • I2C: One I2C peripheral (pins D4/D5)
  • SPI: One SPI peripheral (pins D8/D9/D10)
  • UART: One UART peripheral (pins D6/D7)

Special Features

  • RGB LED: Built-in programmable RGB LED (reversed logic)
  • BOOT Button: Hold for bootloader mode
  • Reset Button: Single press to reset
  • Compact Size: 21mm x 17.8mm - perfect for wearables
  • XIAO Compatible: Works with XIAO expansion boards

Bootloader Mode

To enter bootloader mode:

  1. Hold BOOT button
  2. Connect USB-C cable
  3. Release BOOT button
  4. Board appears as RPI-RP2 drive

Reset

To reset the board:

  1. Press RESET button once while connected
  2. Board will restart current program

Tags

microcontroller, rp2040, xiao, seeed, usb-c, circuitpython, micropython, arduino, compact, breadboard-friendly

Notes

Perfect for wearable devices and small projects requiring powerful processing in a tiny form factor. Compatible with the entire XIAO ecosystem of expansion boards. The built-in RGB LED uses reversed logic (pull low to enable). Supports multiple programming environments including Arduino IDE, CircuitPython, and MicroPython. Easy bootloader mode access by holding B button while connecting USB.

Graph View

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