Installing an executable or MicroPython script on a Pico to run without a computer attached

Question

I've searched and not found an answer.. I'm proficient in C and Micro-python and developing and running programs is easy enough.

However I can't figure out how I install a program I've written to the Pico so that when I supply it purely power it runs?

With ESP32 devices I would normally flash the program to NVMe ram and configure uboot to run it.

Answer 1

Using Thonny save your MicroPython file to the pico as a file called main.py

Next time you power on the Pico your program should autostart.

See section 4.1.1:

https://datasheets.raspberrypi.org/pico/raspberry-pi-pico-python-sdk.pdf

Answer 2

Or, if you don't want to use Thonny (I prefer to choose my own development environment), you can use ampy, a command-line tool for micropython boards.

Example usage:

ampy -p /dev/ttyACM0 put main.py

Note that to auto-run, your Python file needs to be called main.py.

Answer 3

I met only with failure to have main.py run on the Pico at boot until I realized the file had been saved on the Pico through Thonny WITHOUT the .py extension. Ridiculous, but it may explain why many have had the same problem.

Answer 4

In order to upload a Python script with ampy or rshell as mentioned in the answers above, one may need to add itself to dialout group to be able to upload without sudo. Note re-login is needed for the group change to take effect

sudo usermod -aG dialout $USER

By default on my Ubuntu, Pico's serial port is owned by root user and dialout group so an ordinal user cannot access it

ls -l /dev/ttyACM1
crw-rw---- 1 root dialout 166, 1 Mar  7 09:57 /dev/ttyACM1

Answer 5

Or with rshell instead of ampy:

python3 -m pip install --user rshell
rshell -p /dev/ttyACM0 --buffer-size 512 cp blink.py /pyboard/main.py

See also: https://stackoverflow.com/questions/66183596/how-can-you-make-a-micropython-program-on-a-raspberry-pi-pico-autorun/74078142#74078142