Datasheet

SAM9263 [DATASHEET]
Atmel-6249N-ATARM-SAM9263-Datasheet_14-Mar-16
640
The propagation segment time is equal to twice the sum of the signal’s
propagation time on the bus line, the receiver delay and the output driver
delay:
Tprs = 2 * (50+30+110) ns = 380 ns = 3 Tcsc
=> PROPAG = Tprs/Tcsc - 1 = 2
The remaining time for the two phase segments is:
Tphs1 + Tphs2 = bit time - Tcsc - Tprs = (16 - 1 - 3)Tcsc
Tphs1 + Tphs2 = 12 Tcsc
Because this number is even, we choose Tphs2 = Tphs1 (else we would choose Tphs2
= Tphs1 + Tcsc)
Tphs1 = Tphs2 = (12/2) Tcsc = 6 Tcsc
=> PHASE1 = PHASE2 = Tphs1/Tcsc - 1 = 5
The resynchronization jump width must be comprised between 1 Tcsc and the
minimum of 4 Tcsc and Tphs1. We choose its maximum value:
Tsjw = Min(4 Tcsc,Tphs1) = 4 Tcsc
=> SJW = Tsjw/Tcsc - 1 = 3
Finally: CAN_BR = 0x00053255
36.6.4.2 CAN Bus Synchronization
Two types of synchronization are distinguished: “hard synchronization” at the start of a frame and
“resynchronization” inside a frame. After a hard synchronization, the bit time is restarted with the end of the
SYNC_SEG segment, regardless of the phase error. Resynchronization causes a reduction or increase in the bit
time so that the position of the sample point is shifted with respect to the detected edge.
The effect of resynchronization is the same as that of hard synchronization when the magnitude of the phase error
of the edge causing the resynchronization is less than or equal to the programmed value of the resynchronization
jump width (t
SJW
).
When the magnitude of the phase error is larger than the resynchronization jump width and
 the phase error is positive, then PHASE_SEG1 is lengthened by an amount equal to the resynchronization
jump width.
 the phase error is negative, then PHASE_SEG2 is shortened by an amount equal to the resynchronization
jump width.