Seeed Studio Xiao RP2040
The Seeed Studio Xiao RP2040 is a general purpose board supplied by Seeed Studio and it is compatible with the Raspberry Pi RP2040 ecosystem as they share the same RP2040 chip.
Features
RP2040 microcontroller chip
Dual-core ARM Cortex M0+ processor, flexible clock running up to 133 MHz
264KB of SRAM, and 2MB of onboard Flash memory
11 digital pins, 4 analog pins, 11 PWM Pins
1 I2C interface, 1 UART interface, 1 SPI interface, 1 SWD Bonding pad interface
USB Type-C interface
1 user LED, 1 power LED, two LEDs for serial port downloading, 1 RGB LED
1 RESET button, 1 BOOT button
Serial Console
By default a serial console appears on pins 6 (TX GPIO0) and pin 7 (RX GPIO1). This console runs a 115200-8N1. The board can be configured to use the USB connection as the serial console.
LEDs
There are 2 LEDs available for user:
A RGB LED connected to GPIO16 (PIN_LED_G), GPIO17 (PIN_LED_R), GPIO25 (PIN_LED_B).
A NeoPixel RGB LED connected to GPIO11 (NEOPIXEL_POWER) and GPIO12 (PIN_NEOPIXEL).
Pin Mapping
Pads numbered anticlockwise from USB connector.
Pad |
Signal |
Notes |
|---|---|---|
0 |
GPI26 |
D0/A0 |
1 |
GPI27 |
D1/A1 |
2 |
GPI28 |
D2/A2 |
3 |
GPI29 |
D3/A3 |
4 |
GPIO6 |
D4/SDA |
5 |
GPIO7 |
D5/SCL |
6 |
GPIO0 |
Default TX for UART0 serial console |
7 |
GPIO1 |
Default RX for UART1 serial console/CSn |
8 |
GPIO2 |
D8/SCK |
9 |
GPIO3 |
D10/MOSI |
10 |
GPIO4 |
D9/MicroSD |
11 |
3V3 |
Power output to peripherals |
12 |
Ground |
|
13 |
VIN |
+5V Supply to board |
Power Supply
For general I/O pins:
Working voltage of MCU is 3.3V. Voltage input connected to general I/O pins may cause chip damage if it’ higher than 3.3V.
For power supply pins:
The built-in DC-DC converter circuit able to change 5V voltage into 3.3V allows to power the device with a 5V supply via VIN-PIN and via the USB connector.
Installation
Download Raspberry Pi Pico SDK.
$ git clone -b 2.0.0 https://github.com/raspberrypi/pico-sdk.git
Download and install picotool
Instructions can be found here: https://github.com/raspberrypi/picotool
If you are on Arch Linux, you can install the picotool through the AUR:
$ yay -S picotool
Set PICO_SDK_PATH environment variable
$ export PICO_SDK_PATH=<absolute_path_to_pico-sdk_directory>
Configure and build NuttX
$ git clone https://github.com/apache/nuttx.git nuttx
$ git clone https://github.com/apache/nuttx-apps.git apps
$ cd nuttx
$ make distclean
$ ./tools/configure.sh seeed-xiao-rp2040:nsh
$ make V=1
Connect the Seeed Studio Xiao RP2040 board to USB port while pressing BOOTSEL (small button marked “B”). The board will be detected as USB Mass Storage Device. Then copy “nuttx.uf2” into the device. (Same manner as the standard Pico SDK applications installation)
To access the console, GPIO 0 and 1 pins must be connected to the device such as USB-serial converter.
usbnsh configuration provides the console access by USB CDC/ACM serial device. The console is available by using a terminal software on the USB host.
Configurations
nsh
Basic NuttShell configuration (console enabled in UART0, at 115200 bps).
userled
This is an nsh configuration with added support for user LEDs.
usbnsh
Basic NuttShell configuration using CDC/ACM serial (console enabled in USB Port, at 115200 bps).
License exceptions
The following files are originated from the files in Pico SDK. So, the files are licensed under 3-Clause BSD same as Pico SDK.
arch/arm/src/rp2040/rp2040_clock.c
arch/arm/src/rp2040/rp2040_pll.c
arch/arm/src/rp2040/rp2040_xosc.c
These are created by referring the Pico SDK clock initialization.
arch/arm/src/rp2040/rp2040_pio.c
arch/arm/src/rp2040/rp2040_pio.h
arch/arm/src/rp2040/rp2040_pio_instructions.h
These provide the similar APIs to Pico SDK’s hardware_pio APIs.
arch/arm/src/rp2040/hardware/*.h
These are generated from rp2040.svd originally provided in Pico SDK.