DESIGN OF A CUSTOM ASIC INCORPORATING CAN™ AND 1 ...

transmitting again if the fault condition is removed [21]. The rest of the network will continue to
work even if a node is set to Bus-Off.
3.6 CAN Bit Timing Requirements
One beneficial feature of the CAN protocol is that the bit rate, bit sample point and
number of samples per bit are completely programmable by the system designer. This provides
the opportunity to optimize the performance of the network for a given application. Even if
minor errors in the configuration of the CAN bit timing do not result in immediate failure, the
performance of a CAN network can be reduced significantly if not properly tuned.
In many cases, the CAN bit synchronization will amend a faulty configuration of the
CAN bit timing to such a degree that only occasionally an Error Frame is generated. In the
case of arbitration however, when two or more CAN nodes simultaneously try to transmit a
frame, a misplaced sample point may cause one of the transmitters to become Error-Passive.
The analysis of such sporadic errors requires a detailed knowledge of the CAN bit
synchronization inside a CAN node and of the CAN nodes’ interaction on the CAN bus
[19].
3.6.1 CAN Bit Structure
The Nominal Bit Rate of any CAN network is uniform throughout and is given by:
f
NBT
65
1
(3.2)
t
NBT