Nominal bit time
SYNCSEG
1 TQ
TSEG2TSEG1
Transmit point
Sample point
SJW SJW
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eCAN Configuration
789
SPRUI07–March 2020
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Controller Area Network (CAN)
In the eCAN module, the length of a bit on the CAN bus is determined by the parameters TSEG1 (BTC.6-
3), TSEG2 (BTC.2-0), and BRP (BTC.23.16).
TSEG1 combines the two time segments PROP_SEG and PHASE_SEG1 as defined by the CAN
protocol. TSEG2 defines the length of the time segment PHASE_SEG2.
IPT (information processing time) corresponds to the time necessary for the processing of the bit read. IPT
corresponds to two units of TQ.
The following bit timing rules must be fulfilled when determining the bit segment values:
• TSEG1(min) ≥ TSEG2
• IPT ≤ TSEG1 ≤ 16 TQ
• IPT ≤ TSEG2 ≤ 8 TQ
• IPT = 3/BRP (the resulting IPT has to be rounded up to the next integer value)
• 1 TQ ≤ SJW min[4 TQ, TSEG2] (SJW = Synchronization jump width)
• To utilize three-time sampling mode, BRP ≥ 5 has to be selected
Figure 13-7. CAN Bit Timing
A TSEG1 can be lengthened or TSEG2 shortened by the SJW
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