Developing on Raspberry Pico env

Mandatory elements/progs for developing on Pico:
To do some development on this project or just use it, you may need to execute the following steps if you never made it:

1. Install git
2. Install CMake
3. Install GNU Arm Embedded Toolchain
4. Install and configure Raspberry Pico SDK

Setup on Linux environment

1. Install git

$ sudo apt-get install git

2. Install CMake

$ sudo apt-get install cmake

3. Install ARM embedded toolchain

1. Step one
   Download the arm compiler suite from ARM official website. You will get a gcc-arm-none-eabi-x.x.x-xxx64-linux.tar.bz2 file. It contains the full
   Go to the folder where your file was downloaded, the x are the last version, date and architecture you need for your Linux arch. For me it was the x86_64.

2. Step two
   The second step is to install all this compiler suite somewhere you want. It is important to choose it well because you will need top add it to your PATH.

$ sudo tar xjf gcc-arm-none-eabi-10.3-2021.10-x86_64-linux.tar.bz2 -C /your/path/

3. Step three
   Third step: add compiler suite to PATH:

$ echo 'export PATH=$PATH:/your/path/gcc-arm-none-eabi/bin' | sudo tee -a /etc/profile.d/gcc-arm-none-eabi.sh

4. Install and configure Raspberry pico-sdk

1. Step one get pico-sdk
   Clone PICO-SDK project from github in /opt/pico-sdk/ but you may give another place:

$ sudo git clone https://github.com/raspberrypi/pico-sdk.git /opt/pico-sdk

2. Step two Initialize sub-modules
   Just do it, be careful with path

$ sudo git -C /opt/pico-sdk submodule update --init

3. Step three add it to PATH
   Project's cmake files will use the $ENV{PICO_SDK_PATH} variable to get pico-sdk libraries. Make sure your PATH has the link to the pico-sdk, otherwise CMake will not work.

$ echo 'export PICO_SDK_PATH=/opt/pico-sdk' | sudo tee -a /etc/profile.d/pico-sdk.sh

Setup on MacOS

@todo

Compile and load program on target

Compile

To compile, it is the same process as with usual CMake project, just a small last step need to be done.
After you generated the compiling scripts with CMake, just make won't work, do instead:

$ make -j$(nproc)

It will generate a lot of files, elf files and a .uf2 file which will be our executable to be loaded on target.

Flash

To flash and execute, Raspberry Pico behaves like an USB mass storage device you need to mount. After mounted, you can copy the executable.uf2 file on it, it will execute by itself automatically.

Find the Raspberry Pico:
Either on the file explorer if mounted, or on terminal:

$ sudo blkid -o list | grep RPI-RP2

Output:

/dev/sdb1 vfat RPI-RP2 (not mounted) 0034-04C4

Then create a directory for it to be mounted and mount it:

$ sudo mkdir /mnt/pico
$ sudo mount /dev/sdb1 /mnt/pico

Be careful with the sdb1 port! It may be another name.

You should then find the following files in the RPI-RP2 directory:

INDEX.HTM INFO_UF2.TXT

Load executable on target
Copy program on target and flush memory buffer to the storage device:

$ sudo cp myapp.uf2 /mnt/pico
$ sudo sync

Check output
The stdio of Raspberry Pico can be found on the /dev/ttyACM0 port.
To read it, either do it with minicom or screen program, baudrate is 115200 bauds.

$ sudo screen /dev/ttyACM0 115200

Be aware, it may be another tty. To know which tty you have, run the following command:

$ dmesg | grep tty