MC68908GZ8MFJE Datasheet, PDF (144/314 Pages) Freescale Semiconductor, Inc – Microcontrollers

MSCAN08 Controller (MSCAN08)
WUPM — Wakeup Mode
This flag defines whether the integrated low-pass filter is applied to protect the MSCAN08 from
spurious wakeups (see 12.8.5 Programmable Wakeup Function).
1 = MSCAN08 will wakeup the CPU only in cases of a dominant pulse on the bus which has a length
of at least t_wup.
0 = MSCAN08 will wakeup the CPU after any recessive-to-dominant edge on the CAN bus.
CLKSRC — Clock Source
This flag defines which clock source the MSCAN08 module is driven from (see 12.10 Clock System).
1 = The MSCAN08 clock source is CGMOUT (see Figure 12-8).
0 = The MSCAN08 clock source is CGMXCLK/2 (see Figure 12-8).
NOTE
The CMCR1 register can be written only if the SFTRES bit in the MSCAN08
module control register is set
12.13.3 MSCAN08 Bus Timing Register 0
Address:
Read:
Write:
Reset:
$0502
Bit 7
6
5
4
3
2
1
SJW1
SJW0
BRP5
BRP4
BRP3
BRP2
BRP1
0
0
0
0
0
0
0
Figure 12-18. Bus Timing Register 0 (CBTR0)
Bit 0
BRP0
0
SJW1 and SJW0 — Synchronization Jump Width
The synchronization jump width (SJW) defines the maximum number of time quanta (T_q) clock cycles
by which a bit may be shortened, or lengthened, to achieve resynchronization on data transitions on
the bus (see Table 12-6).
Table 12-6. Synchronization Jump Width
SJW1
0
0
1
1
SJW0
0
1
0
1
Synchronization
Jump Width
1 T_q cycle
2 T_q cycle
3 T_q cycle
4 T_q cycle
BRP5–BRP0 — Baud Rate Prescaler
These bits determine the time quanta (T_q) clock, which is used to build up the individual bit timing,
according to Table 12-7.
MC68HC908GZ16 • MC68HC908GZ8 Data Sheet, Rev. 4
144
Freescale Semiconductor