bus.rst

Bus

The ~can.BusABC class, as the name suggests, provides an abstraction of a CAN bus. The bus provides a wrapper around a physical or virtual CAN Bus. An interface specific instance of the ~can.BusABC is created by the ~can.Bus class, for example:

vector_bus = can.Bus(interface='vector', ...)

That bus is then able to handle the interface specific software/hardware interactions and implements the ~can.BusABC API.

A thread safe bus wrapper is also available, see Thread safe bus.

Autoconfig Bus

can.Bus

API

can.BusABC

__iter__

Transmitting

Writing individual messages to the bus is done by calling the ~can.BusABC.send method and passing a ~can.Message instance. Periodic sending is controlled by the broadcast manager <bcm>.

Receiving

Reading from the bus is achieved by either calling the ~can.BusABC.recv method or by directly iterating over the bus:

for msg in bus:
    print(msg.data)

Alternatively the ~can.Listener api can be used, which is a list of ~can.Listener subclasses that receive notifications when new messages arrive.

Filtering

Message filtering can be set up for each bus. Where the interface supports it, this is carried out in the hardware or kernel layer - not in Python.

Thread safe bus

This thread safe version of the ~can.BusABC class can be used by multiple threads at once. Sending and receiving is locked separately to avoid unnecessary delays. Conflicting calls are executed by blocking until the bus is accessible.

It can be used exactly like the normal ~can.BusABC:

# 'socketcan' is only an example interface, it works with all the others too my_bus = can.ThreadSafeBus(interface='socketcan', channel='vcan0') my_bus.send(...) my_bus.recv(...)

can.ThreadSafeBus