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Chapter 16
CAN Controller
User’s Manual U16504EE1V1UD00
16.2.7 Baud Rate Control Function
(1)
Nominal bit time (8 to 25 time quanta)
Definition of 1 data bit time is as follows.
Figure 16-16:
Nominal Bit Time (8 to 25 Time Quanta)
Sync segment: In this segment the bit synchronization is performed.
Prop segment: This segment absorbs delays of the output buffer, the CAN bus and the input
buffer. Prop segment time
=
(output buffer delay) + (CAN bus delay) + (input buffer delay).
Phase segment 1/2: These segments compensate the data bit time error. The larger the size
measured in TQ is, the larger is the tolerable error.
The synchronization jump width (SJW) specifies the synchronization range. The SJW is
programmable. SJW can have less or equal number of TQ as phase segment 2.
Table 16-15:
Segment Name and Segment Length
Note:
IPT = Information Processing Time. It needs to be less than or equal to 2 TQ.
Segment Name
Segment Length
(allowed Number of TQs)
Sync segment
(Synchronization segment)
1
Prop segment
(Propagation segment)
Programmable 1 to 8
Phase segment 1
(Phase buffer segment 1)
Programmable 1 to 8
Phase segment 2
(Phase buffer segment 2)
Maximum of phase segment 1
and the IPT
Note
SJW
Programmable 1 to 4
Sync
segment
Prop
segment
Phase
segment 1
Phase
segment 2
Nominal bit time
SJW
SJW
Sample point
[1 Minimum time for one time/quantum (TQ) = 1/fx]
