Datasheet

V850ES/JG3-H, V850ES/JH3-H CHAPTER 20 CAN CONTROLLER
R01UH0042EJ0500 Rev.5.00 Page 915 of 1513
Aug 12, 2011
Remark The CAN protocol specification defines the segments constituting the data bit time as shown in Figure 20-19.
Figure 20-19. Configuration of Data Bit Time Defined by CAN Specification
Phase segment 1Prop segmentSync segment
Phase segment 2
Sample point (SPT)
SJW
Data bit time (DBT)
Segment name Segment length Description
Sync segment
(Synchronization segment)
1
This segment starts at the edge where the level changes
from recessive to dominant when hardware synchronization
is established.
Prop segment
(Propagation segment)
Programmable to 1 to 8,
or greater
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)
Phase segment 1
(Phase buffer segment 1)
Programmable to 1 to 8
Phase segment 2
(Phase buffer segment 2)
Phase segment 1 or IPT,
whichever greater
This segment compensates for an error in the data bit time.
The longer this segment, the wider the permissible range
but the slower the communication speed.
SJW
(reSynchronization Jump
Width)
Programmable from 1TQ
to segment 1TQ to 4TQ,
whichever is smaller
This width sets the upper limit of expansion or contraction
of the phase segment during resynchronization.
Remark IPT: Information Processing Time
TQ: Time Quanta