mc9s12xs128 Freescale Semiconductor, Inc, mc9s12xs128 Datasheet - Page 340

• Manufacturer Part Number: mc9s12xs128
• Description: Hcs12 Microcontrollers 16-bit Automotive Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Freescale’s Scalable Controller Area Network (S12MSCANV3)
The synchronization jump width (see the Bosch CAN specification for details) can be programmed in a
range of 1 to 4 time quanta by setting the SJW parameter.
The SYNC_SEG, TSEG1, TSEG2, and SJW parameters are set by programming the MSCAN bus timing
registers (CANBTR0, CANBTR1) (see
and
Table 11-37
11.4.4
11.4.4.1
The MSCAN module behaves as described within this specification in all normal system operating modes.
Write restrictions exist for some registers.
340
Section 11.3.2.4, “MSCAN Bus Timing Register 1
Time Segment 1
Modes of Operation
gives an overview of the CAN compliant segment settings and the related parameter values.
Normal System Operating Modes
5 .. 10
4 .. 11
5 .. 12
6 .. 13
7 .. 14
8 .. 15
9 .. 16
It is the user’s responsibility to ensure the bit time settings are in compliance
with the CAN standard.
Transmit Point
Sample Point
SYNC_SEG
Syntax
Table 11-37. CAN Standard Compliant Bit Time Segment Settings
TSEG1
3 .. 10
4 .. 11
5 .. 12
6 .. 13
7 .. 14
8 .. 15
4 .. 9
S12XS Family Reference Manual, Rev. 1.10
System expects transitions to occur on the CAN bus during this
period.
A node in transmit mode transfers a new value to the CAN bus at
this point.
A node in receive mode samples the CAN bus at this point. If the
three samples per bit option is selected, then this point marks the
position of the third sample.
Table 11-36. Time Segment Syntax
Time Segment 2
Section 11.3.2.3, “MSCAN Bus Timing Register 0
2
3
4
5
6
7
8
NOTE
(CANBTR1)”).
Description
TSEG2
1
2
3
4
5
6
7
Synchronization
Jump Width
1 .. 2
1 .. 3
1 .. 4
1 .. 4
1 .. 4
1 .. 4
1 .. 4
Freescale Semiconductor
(CANBTR0)”
SJW
0 .. 1
0 .. 2
0 .. 3
0 .. 3
0 .. 3
0 .. 3
0 .. 3