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Microcontroller · Development Board
Seeed Studio XIAO RA4M1
XIAO-format RA4M1, the UNO R4's microcontroller, running at 3.3 V with 19 GPIO.
- GPIO
- I2C
- SPI
- UART
- ADC
- DAC
- PWM
- CAN
- USB
- Processor
- Renesas RA4M1 (Cortex-M4 @ 48 MHz)
- Logic
- 3.3 V GPIOTreat as not 5 V tolerant
- Power
- USB-C, battery pads, 5 V/3.3 V pins
- Format
- Tiny castellated module (21 x 17.8 mm)
Before you wire
3 cautions- 3.3 V GPIO on this board, even though the RA4M1 runs at 5 V on the UNO R4 and Nano R4. Do not reuse 5 V shield wiring.
- CAN (CRX0/CTX0 on D9/D10) needs an external transceiver and shares those pads with SPI1.
- P112/P500 drive the RGB LED and P011 the user LED.
Pin map
Connector
XIAO 14 castellated pads
USB-C at top, component side up, 7 pads down each long edge
Simplified technical illustration. Pin data is source-backed; verify against the linked documentation before wiring.
Pin
Hover, tap, or arrow to a pad to inspect it.
- USB-C at top, component side up; labels follow Seeed's XIAO RA4M1 pin map, schematic, and the Zephyr xiao_d connector map.
- The RA4M1 runs from the board's 3.3 V rail here, unlike the 5 V UNO R4 and Nano R4.
- Back-side pads D11-D18 are not shown on this 14-pad map.
All 14 pins (table)
| # | Signal | Role | Net | Also / notes |
|---|---|---|---|---|
| 1 | ADC | P014 / AN009 / DAC | ||
| 2 | ADC | P000 / AN000 | ||
| 3 | ADC | P001 / AN001 | ||
| 4 | ADC | P002 / AN002 | ||
| 5 | I2C | I2C | P206 / SDA1 | |
| 6 | I2C | I2C | P100 / SCL1 · Also an analog input when I2C is not in use. | |
| 7 | UART | UART | P302 / TXD2 | |
| 14 | Power | 5V | ||
| 13 | Ground | GND | ||
| 12 | Power | 3V3 | ||
| 11 | SPI | SPI | P109 / CTX0 | |
| 10 | SPI | SPI | P110 / CRX0 | |
| 9 | SPI | SPI | P111 | |
| 8 | UART | UART | P301 / RXD2 |
Source references
Why it matters
- Native USB on the RA4M1; no separate USB bridge.
- Five analog inputs on the edge pads, with the DAC on D0 (P014).
- Back pads add a second UART and more analog-capable GPIO.
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