python-can-usb8dev

✍️ Written with Claude Opus 4.8.

A pure-Python python-can backend for the 8devices USB2CAN / Korlan adapter (VID 0483, PID 1234).

It reimplements the vendor usb2can.dll (CANAL API) entirely in Python, speaking the device's native usb_8dev USB protocol directly over libusb — no vendor DLL and no python-can usb2can/CANAL interface. The protocol matches the mainline Linux kernel driver drivers/net/can/usb/usb_8dev.c (used as documentation, not copied). Works on Windows, macOS, and Linux.

Install

pip install python-can-usb8dev

This pulls in python-can, pyusb, and libusb-package (which vendors the libusb-1.0 native library as a wheel, so nothing native needs to be installed separately).

Use

It registers itself as the python-can interface usb8dev, so it behaves like any built-in backend:

import can

print(can.detect_available_configs(interfaces=["usb8dev"]))   # find adapters

with can.Bus(interface="usb8dev", channel="ED000001", bitrate=250000) as bus:
    for msg in bus:
        print(msg)

Works with python-can's CLIs too:

can_logger -i usb8dev -c ED000001 -b 250000 -f capture.asc
can_viewer -i usb8dev -c ED000001 -b 250000

Options

Standalone recorder

The package also installs a small recorder / test harness, handy to confirm an adapter works on its own:

usb8dev-record --list                      # list connected adapters
usb8dev-record -b 250000                    # print frames live
usb8dev-record -b 250000 -o capture.asc     # + log to file (.asc/.blf/.csv/.log)
usb8dev-record -b 250000 --loopback         # self-test with no bus attached

(Equivalently python -m can_usb8dev ….)

Driver setup

• Windows — the adapter must be bound to a libusb-compatible driver. The 8devices WinUSB package binds WinUSB, which libusb drives; otherwise use Zadig to bind WinUSB or libusbK.
• macOS — no driver setup: no kernel driver claims this vendor device, so libusb talks to it directly.
• Linux — the mainline usb_8dev SocketCAN driver is the native path (ip link set can0 up type can bitrate 250000); this package is mainly useful on platforms without SocketCAN, but works on Linux too via libusb (detach the kernel driver first if it has claimed the device).

How it works

• Bit timing is solved from the 32 MHz device clock at an 87.5% sample point (e.g. 250k → brp=8, tseg1=13, tseg2=2, sjw=2).
• Four bulk endpoints: data RX/TX and command RX/TX. A 16-byte command message (start 0x11 / end 0x22, reply opt1==0 == success) carries OPEN/CLOSE with timing + mode flags; CAN frames use fixed 21-byte (RX) / 16-byte (TX) framed messages with start 0x55 / end 0xAA.

License

MIT