DS80C390_00 Datasheet, PDF (123/155 Pages) Dallas Semiconductor – High-Speed Microcontroller User’s Guide Supplement

DS80C390 High-Speed Microcontroller User’s Guide Supplement
CAN Bus Timing Register 0 (CnBT0)
MOVX
Address¹
7
6
5
4
3
2
1
0
xxxx04h SJW1 SJW0 BPR5 BPR4 BPR3 BPR2 BPR1 BPR0
SJW1, SJW0
Bits 7-6
BPR5 - BPR0
Bits 5-0
CAN Synchronization Jump Width Select. These bits specify the maximum
number of time quanta (t_qu) cycles that a bit may be lengthened or shortened in
one resynchronization to compensate for Phase Errors detected by the CAN
controller when receiving data. These bits can only be modified during a software
initialization (SWINT=1).
SJW1 SJW0 Synchronization Jump Width
(Number in parenthesis is SJW value used in bit timing calculations)
0
0 1 t_qu (1)
0
1 2 t_qu (2)
1
0 3 t_qu (3)
1
1 4 t_qu (4)
CAN Baud Rate Prescaler. The sixty four states defined by the binary
combinations of the BPR5 - BPR0 bits determine the value of the prescaler,
which in turn defines the cycle time associated with one time quanta. These bits
can only be modified during a software initialization (SWINT=1).
BPR5
0
0
.
.
1
1
BPR4
0
0
.
.
1
1
BPR3
0
0
.
.
1
1
BPR2
0
0
.
.
1
1
BPR1
0
0
.
.
1
1
BPR0
0
1
.
.
0
1
Baud Rate Prescale Value
(BRPV)
1
2
.
.
63
64
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