PicoHs

A line following algorithm implemented with MicroHs for the Raspberry Pi Go powered by a Raspberry Pi Pico.

Building the project

To compile the application, the following build tools must be installed (package names from Arch Linux):

cmake
arm-none-eabi-gcc
arm-none-eabi-newlib

Raspberry Pi Pico 2040

To build the application for the Raspberry Pi Pico 2040, execute the following commands:

cmake -B build
cmake --build build

Raspberry Pi Pico 2040 W

To build the application for the Raspberry Pi Pico W, execute the following commands:

cmake -B build -DPICO_BOARD=pico_w -DWIFI_SSID="Your Network" -DWIFI_PASSWORD="Your Password"
cmake --build build

The options -DWIFI_* can be omitted if you do not intend to use WiFi.

Raspberry Pi Pico 2350

To build the application for the Raspberry Pi Pico 2350, execute the following commands:

cmake -B build -DPICO_PLATFORM=rp2350
cmake --build build

Flashing

To copy the application to the Pico, press the BOOTSEL button when switching on. This will mount the Pico as a USB device. You can now copy the application to the Pico:

cp build/pico-go.uf2 <pico-mount-point>

After making changes to the source code, it is sufficient to execute cmake --build build again. If you have changed anything in the cmake files, you need to execute cmake -B build (see build instructions for your platform) again, followed by cmake --build build.

Monitor console / Debugging

The Pico.hs module provides the print and printLn functions. These two functions can be used to log to the console. Once you have connected the Pico to your PC via USB and copied the program, you can use minicom to connect to the Pico's console:

minicom -b 115200 -o -D /dev/ttyACM0

Run PicoGo

1. Copy the application to the PicoGo
2. Unplug USB Cable
3. Switch the PicoGo on (switch on the underside)

It is recommended to place the PicoGo on a white paper with a black line during initialization. The PicoGo will drive better on the line.

PIO / SPI

To communicate with the sensors the Serial peripheral interface (SPI) is used. The Raspberry Pi Pico provides the PIO (Programmable Input/Output) to use the SPI.

Prototypes and contributions

In order to learn how to build an application with MicroHs for an micro controller, two proof of concepts were developed.

• Arduino Uno Prototype
• Raspberry Pi Pico Prototype

During the development of this project, issues and pull requests were created for MicroHs:

• Issue - mhs: error: no location: Not a valid C type: () #70
• Pull Request - Remove Primitives prefix
• Pull request - Implement clamp in Data.Ord
• Issue - Segmentation fault (core dumped)

To keep everything in one place, the diffs and patches are stored in the MicroHs_Contributions folder.