PXS20RM Datasheet, PDF (640/1368 Pages) Freescale Semiconductor, Inc – PXS20 Microcontroller

FlexCAN Module
• Time Segment 2: This segment represents the Phase Segment 2 of the CAN standard. It can be
programmed by setting the PSEG2 field of the CTRL Register (plus 1) to be 2 to 8 time quanta long
Bit Þ Rate= -----------------------------------------^f--^T---^q------------------------------------------
number Þ of Þ Time Þ Quanta
NRZ Signal
SYNC_SEG
Time Segment 1
(PROP_SEG + PSEG1 + 2)
Time Segment 2
(PSEG2 + 1)
1
4 ... 16
8 ... 25 Time Quanta
= 1 Bit Time
2 ... 8
Transmit Point
Sample Point
(single or triple sampling)
Figure 24-15. Segments within the Bit Time
Table 24-9. Time Segment Syntax
Syntax
SYNC_SEG
Transmit Point
Sample Point
Description
System expects transitions to occur on the bus
during this period.
A node in transmit mode transfers a new value to
the CAN bus at this point.
A node 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 24-10 gives an overview of the CAN compliant segment settings and the related parameter values.
Table 24-10. CAN Standard Compliant Bit Time Segment Settings
Time Segment 1
5 .. 10
4 .. 11
5 .. 12
6 .. 13
7 .. 14
8 .. 15
Time Segment 2
2
3
4
5
6
7
Re-synchronization Jump
Width
1 .. 2
1 .. 3
1 .. 4
1 .. 4
1 .. 4
1 .. 4
24-40
PXS20 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor