Datasheet

MSCAN
Functional Description
MC9S12DP256 — Revision 1.1
MSCAN
The Synchronization Jump Width
1
can be programmed in a range of 1
to 4 time quanta by setting the SJW parameter.
The above parameters are set by programming the MSCAN Bus Timing
Registers (CANBTR0, CANBTR1) (see MSCAN Bus Timing Register 0
(CANBTR0) and MSCAN Bus Timing Register 1 (CANBTR1)).
Figure 101 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.
Table 86 Time Segment Syntax
Syntax Description
SYNC_SEG
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.
1. Reference the Bosch CAN 2.0A/B protocol specification dated September 1991 for bit timing.
Time
Segment 1
TSEG1
Time
Segment 2
TSEG2 Synchronization
Jump Width
SJW
5 .. 10 4 .. 9 2 1 1 .. 2 0 .. 1
4 .. 11 3 .. 10 3 2 1 .. 3 0 .. 2
5 .. 12 4 .. 11 4 3 1 .. 4 0 .. 3
6 .. 13 5 .. 12 5 4 1 .. 4 0 .. 3
7 .. 14 6 .. 13 6 5 1 .. 4 0 .. 3
8 .. 15 7 .. 14 7 6 1 .. 4 0 .. 3
9 .. 16 8 .. 15 8 7 1 .. 4 0 .. 3
Figure 101 CAN Standard Compliant Bit Time Segment Settings
Freescale Semiconductor, I
Freescale Semiconductor, Inc.
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