RM0390 Rev 4 1049/1328
RM0390 Controller area network (bxCAN)
1076
A valid edge is defined as the first transition in a bit time from dominant to recessive bus
level provided the controller itself does not send a recessive bit.
If a valid edge is detected in BS1 instead of SYNC_SEG, BS1 is extended by up to SJW so
that the sample point is delayed.
Conversely, if a valid edge is detected in BS2 instead of SYNC_SEG, BS2 is shortened by
up to SJW so that the transmit point is moved earlier.
As a safeguard against programming errors, the configuration of the Bit Timing Register
(CAN_BTR) is only possible while the device is in Standby mode.
Note: For a detailed description of the CAN bit timing and resynchronization mechanism, refer to
the ISO 11898 standard.
Figure 396. Bit timing
6<1&B6(* %,76(*0(17%6 %,76(*0(17%6
120,1$/%,77,0(
[W
T
W
%6
W
%6
6$03/(32,17 75$160,732,17
1RPLQDO%LW7LPH ; W
T
W
%6
W
%6
ZLWK
W
%6
W
T
[76>@
W
%6
W
T
[76>@
W
T
%53>@[W
3&/.
W
3&/.
WLPHSHULRGRIWKH$3%FORFN
%53>@76>@DQG76>@DUHGHILQHGLQWKH&$1B%755HJLVWHU
%DXG 5DWH
1RPLQDO%LW7LPH
ZKHUHW
T
UHIHUVWRWKH7LPHTXDQWXP
069