mc9s12hz256v2 Freescale Semiconductor, Inc, mc9s12hz256v2 Datasheet - Page 377

• Manufacturer Part Number: mc9s12hz256v2
• Description: Hcs12 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

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 12-36
12.4.4
The MSCAN generates an internal time stamp whenever a valid frame is received or transmitted and the
TIME bit is enabled. Because the CAN specification defines a frame to be valid if no errors occur before
the end of frame (EOF) field is transmitted successfully, the actual value of an internal timer is written at
EOF to the appropriate time stamp position within the transmit buffer. For receive frames, the time stamp
is written to the receive buffer.
Freescale Semiconductor
Section 12.3.2.4, “MSCAN Bus Timing Register 1
Time Segment 1
Timer Link
gives an overview of the CAN compliant segment settings and the related parameter values.
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 12-36. CAN Standard Compliant Bit Time Segment Settings
TSEG1
3 .. 10
4 .. 11
5 .. 12
6 .. 13
7 .. 14
8 .. 15
4 .. 9
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 12-35. Time Segment Syntax
MC9S12HZ256 Data Sheet, Rev. 2.05
Time Segment 2
Section 12.3.2.3, “MSCAN Bus Timing Register 0
2
3
4
5
6
7
8
NOTE
Chapter 12 Freescale’s Scalable Controller Area Network (MSCANV2)
(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
(CANBTR0)”
SJW
0 .. 1
0 .. 2
0 .. 3
0 .. 3
0 .. 3
0 .. 3
0 .. 3
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