NEC V850E/RS1 User Manual page 548

Reference: The CAN protocol specification defines the segments constituting the data bit time as
shown in Figure 16-19.
Figure 16-19: Reference: Configuration of Data Bit Time Defined by CAN Specification
Sync segment
(Synchronization segment)
Prop segment
(Propagation segment)
Phase segment 1
(Phase buffer segment 1)
Phase segment 2
(Phase buffer segment 2)
SJW
(resynchronization Jump
Width)
Note: IPT: Information Processing Time
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Sync segment Prop segment
Segment name Segment length
1
Programmable to 1 to 8
or more great
Programmable to 1 to 8
Phase segment 1 or IPT-
Note
, whichever greater
Programmable from 1
TQ to segment 1TQ to
4TQ, whichever is
smaller
Chapter 16 FCAN Controller
Data bit time(DBT)
Phase segment 1
Sample point (SPT)
This segment starts at the edge where the level
changes from recessive to dominant when hardware
synchronization is established.
This segment absorbs the delay of the output buffer,
CAN bus, and input buffer.
The length of this segment is set so that ACK is
returned before the start of phase segment 1.
Time of prop segment ≥ (Delay of output buffer) + 2 ×
(Delay of CAN bus) + (Delay of input buffer)
This segment compensates for an error in the data bit
time. The longer this segment, the wider the permis-
sible range but the slower the communication speed.
This width sets the upper limit of expansion or con-
traction of the phase segment during resynchroniza-
tion.
User's Manual U16702EE3V2UD00
Phase segment 2
SJW
Description