Seeed Studio XIAO RP2040 with MicroPython

Introduction of MicroPython

MicroPython is a Python interprer with a partial native code compilation feature. It provides a subset of Python 3.5 features, implemented for embedded processors and constrained systems. It is different from CPython and you can read more about the differences here.

Getting Started

First, we are going to connect the Seeed Studio XIAO RP2040 Series to the computer and upload a simple code from MicroPython to check whether the board is functioning well.

Hardware Setup

• Seeed Studio XIAO RP2040 or Seeed Studio XIAO RP2040 Plus x1
• Type-C cable x1
• PC x1

Connect XIAO RP2040 Series to the PC

• Step 1. Press and hold the BOOT button and then connect the Seeed Studio XIAO RP2040 Series to the PC through the Type-C cable. If it works well, there is an RPI-RP2 disk shown on the PC.

• Step 2.Flash the Firmware

  Just go to the official and download the latest firmware, then drag‑and‑drop the .uf2 file into the RPI-RP2 disk to finish firmware flashing.

  • XIAO RP2040 Series MicroPython Firmware

Software Setup

• Step 1. Download and Install the latest version of Thonny editor according to your operating system

• Step 2. Launch the Thonny

• Step 3. Click Tools-->Options to open the settings.

• Step 4. Chose the Interpreter interface and select the device as MicroPython(generic) and the port as Board CDC @ Port

Step 5. Version information will be displayed in the Shell.

Step 6. Go to Files -> New, paste the code below, and run the script.

from machine import Pin, Timer
 
led = Pin(25, Pin.OUT)
Counter = 0
Fun_Num = 0
 
def fun(tim):
    global Counter
    Counter = Counter + 1
    print(Counter)
    led.value(Counter%2)
 
tim = Timer(-1)
tim.init(period=1000, mode=Timer.PERIODIC, callback=fun)

• The LED will blink at 1-second intervals.

tip

• The Additional Resources section contains MicroPython firmware and relevant examples for XIAO RP2040 Plus.You may use these examples by following the XIAO RP2040 tutorials, but make sure to replace and modify the corresponding pins.
• To check the differences within the XIAO RP2040 series, please refer to XIAO RP2040 Series Pin Overview

XIAO RP2040 Series Pins

MicroPython Pin Name	XIAO RP2040 GPIO	XIAO RP2040 Plus GPIO	ADC	Function
D0 / A0	GPIO26	GPIO26	0	GPIO, ADC0
D1 / A1	GPIO27	GPIO27	1	GPIO, ADC1
D2 / A2	GPIO28	GPIO28	2	GPIO, ADC2
D3 / A3	GPIO29	GPIO29	3	GPIO, ADC3
D4 / SDA	GPIO6	GPIO6	—	GPIO, I2C SDA
D5 / SCL	GPIO7	GPIO7	—	GPIO, I2C SCL
D6 / TX	GPIO0	GPIO0	—	GPIO, UART TX
D7 / RX	GPIO1	GPIO1	—	GPIO, UART RX
D8 / SCK	GPIO2	GPIO2	—	GPIO, SPI SCK
D9 / MISO	GPIO4	GPIO4	—	GPIO, SPI MISO
D10 / MOSI	GPIO3	GPIO3	—	GPIO, SPI MOSI
NEOPIXEL	GPIO12	GPIO12	—	WS2812 NeoPixel data
NEOPIXEL_POWER / NEO_PWR / RGB_EN	GPIO11	GPIO11	—	NeoPixel power enable (RGB_EN on Plus)
LED_G / D23	GPIO16	GPIO16	—	RGB LED green; Plus D23
LED_R / D24	GPIO17	GPIO17	—	RGB LED red; Plus D24
LED_B / LED	GPIO25	GPIO25	—	RGB LED blue / user LED
D12	—	GPIO18	—	Plus expansion GPIO
D13 / SCL1	—	GPIO21	—	Plus I2C1 SCL
D14 / SDA1	—	GPIO20	—	Plus I2C1 SDA
D15	—	GPIO19	—	Plus expansion GPIO
D16	—	GPIO22	—	Plus expansion GPIO
D17	—	GPIO23	—	Plus expansion GPIO
D19	—	GPIO5	—	Plus expansion GPIO
D20	—	GPIO13	—	Plus expansion GPIO
D21	—	GPIO14	—	Plus expansion GPIO
D22	—	GPIO15	—	Plus expansion GPIO
D25	—	GPIO10	—	Plus expansion GPIO
D26	—	GPIO9	—	Plus expansion GPIO
D27	—	GPIO8	—	Plus expansion GPIO
BAT_EN	—	GPIO24	—	Plus battery power enable

Light up RGB LED on the Seeed Studio XIAO RP2040

There is an RGB LED equipped in the Seeed Studio XIAO RP2040 and we are going to light it up by MicroPython. It is required a third-party library so we need to add an additional library first.

• Step 1. Download the ws2812.py library and open it with Thonny.

• Step 2. Click File-->Save as and save the library.

Chose the Raspberry Pi Pico as the location we save.

Make sure the saved file name is ws2812.py, otherwise it will not work.

• Step 3. Copy the following codes to Thonny.

from ws2812 import WS2812
import utime
import machine
power = machine.Pin(11,machine.Pin.OUT)
power.value(1)
BLACK = (0, 0, 0)
RED = (255, 0, 0)
YELLOW = (255, 150, 0)
GREEN = (0, 255, 0)
CYAN = (0, 255, 255)
BLUE = (0, 0, 255)
PURPLE = (180, 0, 255)
WHITE = (255, 255, 255)
COLORS = (BLACK, RED, YELLOW, GREEN, CYAN, BLUE, PURPLE, WHITE)

led = WS2812(12,1)#WS2812(pin_num,led_count)

while True:
    print("Beautiful color")
    for color in COLORS: 
        led.pixels_fill(color)
        led.pixels_show()
        utime.sleep(0.2)

• Step 4. Upload the codes by clicking the "Run current script" button. For the first time, Thonny will ask where you want to save your codes file. Both This Computer and Raspberry Pi Pico are fine.

If it works well, you will see the RGB LED light convert and flash the lights. And the output of the text "Beautiful Color" will as well be displayed in the Shell.

Connect with Seeed Studio XIAO RP2040 with Display through IIC

In this project, we are going to connect Grove - OLED Display 0.96" (SSD1315) through the IIC interface to demonstrate the IIC function on the Seeed Studio XIAO RP2040.

Hardware Connect

• Step 1. Download the ssd1306.py library and open it with Thonny.

• Step 2. Click "File-->Save as" and save the library in the "Raspberry Pi Pico"

Chose the "Raspberry Pi Pico" as the location we save.

Make sure the saved file name is "ssd1306.py", otherwise it will not work.

• Step 3. Copy the following codes to Thonny.

from ssd1306 import SSD1306_I2C
from machine import Pin, I2C
from time import sleep

i2c = I2C(1, scl=Pin(7), sda=Pin(6), freq=200000)#Grove - OLED Display 0.96" (SSD1315)
oled = SSD1306_I2C(128, 64, i2c)

while True:  
    oled.fill(0)#clear
    oled.text("Hello,World!",0,0)
    oled.show()
    #sleep(0.5)

• Step 4. Upload the codes by clicking the "Run current script" button. For the first time, Thonny will ask where you want to save your codes file. Both This Computer and Raspberry Pi Pico are fine.

If it works well, you will see the text "Hello,World!" displayed on the screen.

MicroPython Device Console

Our partner Neil has written a command line console program for XIAO using MicroPython. With this programme you can easily upload, download and delete files. We thank him for his contribution to XIAO!

📚 Learn More

Additional Resources

Some additional libraries and sample codes are here:

• [ZIP] XIAO-RP2040-MicroPython-Grove.zip

• [ZIP] XIAO-RP2040-Plus-Firmware-And-Examples

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