Frequently asked questions

What is Cyphal?

Cyphal is an open technology for real-time intravehicular distributed computing and communication based on modern networking standards (Ethernet, CAN FD, etc.). It was created to address the challenge of on-board deterministic computing and data distribution in next-generation intelligent vehicles: manned and unmanned aircraft, spacecraft, robots, and cars. The project was once known as UAVCAN.

How can I deploy PyCyphal on my embedded system?

PyCyphal is mostly designed for high-level user-facing software for R&D, diagnostic, and testing applications. We have Cyphal implementations in other programming languages that are built specifically for embedded systems; please find more info at

PyCyphal seems complex. Does that mean that Cyphal is a complex protocol?

Cyphal is a very simple protocol. This particular implementation may appear convoluted because it is very generic and provides a very high-level API. For comparison, there is a minimal Cyphal-over-CAN implementation in C called libcanard that is only ~1k SLoC large.

I am getting ModuleNotFoundError: No module named 'uavcan'. Do I need to install additional packages?

We no longer ship the public regulated DSDL definitions together with Cyphal implementations in order to simplify maintenance and integration; also, this underlines our commitment to make vendor-specific (or application-specific) data types first-class citizens in Cyphal. Please read the user documentation to learn how to generate Python packages from DSDL namespaces.

Imports fail with AttributeError: module 'uavcan...' has no attribute '...'. What am I doing wrong?

Remove the legacy library: pip uninstall -y uavcan. Read the Installation guide for details.

I am experiencing poor SLCAN read/write performance on Windows. What can I do?

Increasing the process priority to REALTIME (available if the application has administrator privileges) will help. Without administrator privileges, the HIGH priority set by this code, will still help with delays in SLCAN performance. Here’s an example:

if sys.platform.startswith("win"):
    import ctypes, psutil

    # Reconfigure the system timer to run at a higher resolution. This is desirable for the real-time tests.
    t = ctypes.c_ulong()
    ctypes.WinDLL("NTDLL.DLL").NtSetTimerResolution(5000, 1, ctypes.byref(t))
    p = psutil.Process(os.getpid())
elif sys.platform.startswith("linux"):
    p = psutil.Process(os.getpid())