The Controller Area Network (CAN) protocol is an asynchronous serial bus with Non-Return to Zero (NRZ) bit coding designed for fast, robust communications in harsh environments, such as automotive and industrial applications. The CAN protocol allows the user to program the bit rate, the sample point of the bit, and the number of times the bit is sampled. With these features, the network can be optimized for a given application.

There are relationships between bit timing parameters, the physical bus propagation delays, and the oscillator tolerances throughout the system. This application note investigates these relationships as they pertain to Microchip’s CAN module and assists in optimizing the bit timing for given physical system attributes.