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Installing on non-x86 platforms

pyOCD itself is pure Python and should run on any platform with a modern Python installation. However, it has several dependencies with binary backends that cause trouble on non-x86 platforms or alternative operating systems (i.e., not macOS, Linux, or Windows). The most common “non-standard” system that users would like to run pyOCD on is the Raspberry Pi, as well as similar, Arm-based single-board computers.

cmsis-pack-manager

The main dependency that causes trouble is cmsis-pack-manager. It has a backend written in the Rust language to greatly improve performance. Unfortunately, wheels are not available for non-x86 systems. And, worse, the Rust compiler runs out of memory and dies when attempting to build on small platforms such as the Raspberry Pi. (Cross-compilation may be an option but has not been sufficiently investigated.)

The good news is that cmsis-pack-manager is optional for pyOCD. Although it is listed as a required dependency in setup.py (so the vast majority of users benefit from it), pyOCD can run without it with minimal loss of functionality. The pack subcommand is disabled, which removes automatic CMSIS-Pack download and management. But you can still use CMSIS-Packs manually with the --pack option, as described in Target support.

To install pyOCD on such a system, you need to use the pip install --no-deps option. This will install the core pyOCD package only, so all additional requirements must be manually installed. You can either run pip install with an explicit list of the requirements from setup.py, or copy those requirements to a requirements text file and run pip install -r reqs.txt. Of course, be sure to exclude cmsis-pack-manager! (The requirements are not listed here lest they get out of sync with setup.py.)

Once pyOCD is successfully installed, you will need to run it as a module using the python executable as python -mpyocd rather than running the pyocd executable directly. This is because the pyocd executable, which is auto-generated by the install process, verifies dependencies and will error out due to the missing cmsis-pack-manager. But when run through python, dependencies are not checked and pyOCD can handle the lack of cmsis-pack-manager gracefully.

USB interfaces

The other dependencies that might be problematic are those for USB communications. pyOCD uses three USB libraries:

  • pyusb and libusb: CMSIS-DAPv1 on Linux, CMSIS-DAPv2 and STLink on all OSes
  • hidapi: CMSIS-DAPv1 on macOS
  • pywinusb: CMSIS-DAPv1 on Windows

Thankfully, libusb is provided by default on most Linux systems, including Raspberry Pi and similar platforms. So on almost all platforms, USB is not a real problem.

If you are using an alternative OS, you may have trouble finding a functional USB library. In this case, the options would be to port libusb and/or hidapi to your OS, or even to extend pyOCD with support for another USB interface package.