Specifications

CAN Control Registers
10-26
Bits 9–8 SJW. Synchronization jump width
SJW indicates by how many units of TQ a bit is allowed to be lengthened or
shortened when resynchronizing with the receive data stream on the CAN bus.
The synchronization is performed either with the falling edge (SBG = 0) or with
both edges (SBG = 1) of the bus signal. SJW is programmable from 1 to 4 TQ.
Bit 7 SAM. Sample point setting
This parameter sets the number of samples used by the CAN module to deter-
mine the actual level of the CAN bus. When the SAM bit is set, the level deter-
mined by the CAN bus corresponds to the result from the majority decision of
the last three values. The sample points are at the sample point and twice be-
fore with a distance of 1/2 TQ.
0 The CAN module samples only once.
1 The CAN module samples three times and makes a majority decision.
Bits 6–3 TSEG1[3:0]. Time segment 1.
This parameter specifies the length of the TSEG1 segment in TQ units.
TSEG1 combines PROP_SEG and PHASE_SEG1 segments (CAN protocol).
TSEG1 = PROP_SEG + PHASE SEG1.
The value of TSEG1 is programmable from 3 to 16 TQ and must be greater
than or equal to TSEG2.
Bits 2–0 TSEG2[2:0]. Time segment 2.
TSEG2 defines the length of PHASE_SEG2 in TQ units.
When the resynchronization on falling edge only is used (SBG = 0), the mini-
mum TSEG2 value allowed is calculated as follows:
TSEG2
min
1SJW.
=+
The value of TSEG2 is programmable from 2 to 8 TQ in compliance with the
formula:
(SJW SBG 1) TSEG2 8.
++
≤≤