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Raspberry Pico

Flashing a firmware:

  • Hold Bootsel white button while you connect USB

Temperature measurement

The Raspberry Pico includes a temperature sensor. See code

I2C LCD

This is a 1602 screen with a I2C adapter.

  • Download library I2C LCD for Pico
  • Wire SDA, SCL, VCC to VBUS of Pico, and GND. See Pinout.
  • Scan I2C devices to get the I2C address of the LCD screen (it's 0x27):
import machine
sda=machine.Pin(0)
scl=machine.Pin(1)
i2c=machine.I2C(0,sda=sda, scl=scl, freq=400000)
print(i2c.scan())

  • Drop lcd_api.py and pico_i2c_lcd.py on the device, as root. ampy --port /dev/ttyACM0 put filename destination

  • Use the library:

from lcd_api import LcdApi
from pico_i2c_lcd import I2cLcd
i2c = I2C(0, sda=machine.Pin(0), scl=machine.Pin(1), freq=400000)
I2C_ADDR = i2c.scan()[0]
lcd = I2cLcd(i2c, I2C_ADDR, I2C_NUM_ROWS, I2C_NUM_COLS)
lcd.clear()
lcd.putstr("Hello")

Programming in C

  • Setup the Pico SDK: git clone https://github.com/raspberrypi/pico-sdk.git
  • Write the C program
  • Prepare CMakeLists.txt
drwxrwxr-x  3 axelle axelle 4096 Apr 13 22:38 .
drwxrwxr-x 11 axelle axelle 4096 Apr 13 22:32 ..
drwxrwxr-x  7 axelle axelle 4096 Apr 13 22:35 build
-rw-rw-r--  1 axelle axelle  434 Apr 13 22:35 CMakeLists.txt
-rw-rw-r--  1 axelle axelle  193 Apr 13 22:00 greetz.c
-rw-rw-r--  1 axelle axelle 3165 Apr 13 22:17 pico_sdk_import.cmake
  • Compile: cmake .., then make

To push on the board, use picotool

  • Write your .uf2 to the board: sudo picotool load your.uf2
  • Reboot the board in application mode: sudo picotool reboot

You can also save the current firmware (save), or see info:

$ sudo ../picotool/build/picotool info -f
The device was asked to reboot into BOOTSEL mode so the command can be executed.

Program Information
 name:      greetz
 features:  UART stdin / stdout
            USB stdin / stdout

            The device was asked to reboot back into application mode.

References

Screen

Ctrl-A, Ctrl-D to detach screen

Ampy

  • Install: pip install adafruit-ampy
  • List files on the device: ampy --port /dev/ttyACM0 ls
  • Create a directory: ampy --port /dev/ttyACM0 mkdir /lib
  • Put a file on the device ampy --port /dev/ttyACM0 put lcd_api.py ./lib/lcd_api.py
  • Run a file: ampy --port /dev/ttyACM0 run mypython.py