Controller Area Network (FlexCAN)
PXN20 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor 29-37
Figure 29-16. Segments within the Bit Time
Table 29-18 gives an overview of the CAN compliant segment settings and the related parameter values.
NOTE
It is the user’s responsibility to ensure the bit time settings are in compliance
with the CAN standard. For bit time calculations, use an information
processing time (IPT) of 2, which is the value implemented in the FlexCAN
module.
Table 29-17. Time Segment Syntax
Syntax Description
SYNCSEG System expects transitions to occur on the bus during this period.
Transmit Point A node in transmit mode transfers a new value to the CAN bus at this point.
Sample Point A node in receive mode samples the bus at this point. If the three samples per bit
option is selected, then this point marks the position of the third sample.
Table 29-18. CAN Standard Compliant Bit Time Segment Settings
Time Segment 1 Time Segment 2
Resynchronization
Jump Width
5 .. 10 2 1 .. 2
4 .. 11 3 1 .. 3
5 .. 12 4 1 .. 4
6 .. 13 5 1 .. 4
7 .. 14 6 1 .. 4
SYNCSEG
Time Segment 1 Time Segment 2
1 4 ... 16 2 ... 8
8 ... 25 Time Quanta
= 1 Bit Time
NRZ Signal
Sample Point
(single or triple sampling)
(PROPSEG + PSEG1 + 2) (PSEG2 + 1)
Transmit Point
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