mcf51ac256a Freescale Semiconductor, Inc, mcf51ac256a Datasheet - Page 357

• Manufacturer Part Number: mcf51ac256a
• Description: Mcf51ac Flexis
• 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 15-35
Freescale Semiconductor
Section 15.3.4, “MSCAN Bus Timing Register 1
gives an overview of the CAN compliant segment settings and the related parameter values.
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
MCF51AC256 ColdFire Integrated Microcontroller Reference Manual, Rev. 5
Transmit Point
Syntax
SYNC_SEG
1
NRZ Signal
Figure 15-42. Segments within the Bit Time
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 15-34. Time Segment Syntax
(PROP_SEG + PHASE_SEG1)
Section 15.3.3, “MSCAN Bus Timing Register 0
8 ... 25 Time Quanta
Time Segment 1
= 1 Bit Time
4 ... 16
NOTE
(CANBTR1)”).
Description
Sample Point
(single or triple sampling)
Freescale’s Controller Area Network (MSCANV1)
Time Segment 2
(PHASE_SEG2)
2 ... 8
(CANBTR0)”
15-41