了解Microchip的CAN模块的位定时

The Controller Area Network (CAN) protocol is an
asynchronous serial bus with Non-Return to Zero
(NRZ) bit coding designed for fast, robust communica-
tions 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.
M AN754
Understanding Microchip’s CAN Module Bit Timing

Author: Pat Richards
Nominal Bit Time
Microchip Technology Inc. The Nominal Bit Time (NBT), or tbit, is made up of non-
overlapping segments (Figure 1), therefore, the NBT is
INTRODUCTION the summation of the following segments:

The Controller Area Network (CAN) protocol is an t bit = tSyncSeg + t PropSeg + tPS1 + t PS2
asynchronous serial bus with Non-Return to Zero
(NRZ) bit codin