Method and apparatus for determining controller area network (can) bus loading

A controller area network (CAN) node comprising:

• a host processor interface;
• and
• a bus load monitor:
• wherein the host processor interface communicatively couples a host processor to the bus load monitor;
• and
• wherein the bus load monitor is arranged to receive from the host processor an indication of a time window duration of a time window and a threshold range for acceptable bus load in the time window;
• define a start time and an end time for determining a bus load based on the start time and the time window duration;
• determine whether the CAN bus is active or idle for each bit of one or more bits detected on the CAN bus between the start time and the end time;
• determine the bus load over the time window based on whether the CAN bus is active or idle for each bit of the one or more bits detected on the CAN bus between the start time and the end time;
• compare the bus load to the threshold range;
• and send a signal to the host processor if the bus load exceeds or falls below the threshold range.

A bus load monitor of a controller area network (CAN) node is arranged to receive from a host processor an indication of a time window duration of a time window and a threshold range for acceptable bus load in the time window;

• define a start time and an end time for determining a bus load based on the start time and the time window duration;
• detect that a counter indicates the start time;
• receive an indication from a protocol engine (PE) of the CAN node whether the CAN bus is active or idle for bit each of one or more bits detected on the CAN bus;
• determine whether the counter indicates the end time;
• based on the counter not indicating the end time, receive another indication of whether the CAN bus is active or idle for each one of another one or more bits detected on the CAN bus;
• based on the counter indicating the end time, determine the bus load over the time window based on whether the CAN bus is active or idle for each bit of the one or more bits detected on the CAN bus between the start time and the end time;
• compare the bus load to the threshold range;
• and send a signal to the host processor if the bus load exceeds or falls below the threshold range.