MC908AZ60ACFUER Datasheet, PDF (288/414 Pages) Freescale Semiconductor, Inc – To provide the most up-to-date information, the revision of our documents on the World Wide Web will be the most current. Your printed copy may be an earlier revision. To verify you have the latest information available, refer to:

MSCAN Controller (MSCAN08)
23.13.2 MSCAN08 Module Control Register 1
Address: $0501
Read:
Write:
Reset:
Bit 7
6
5
4
3
2
1
0
0
0
0
0
LOOPB WUPM
0
0
0
0
0
0
0
= Unimplemented
Figure 23-16. Module Control Register (CMCR1)
Bit 0
CLKSRC
0
LOOPB — Loop Back Self-Test Mode
When this bit is set, the MSCAN08 performs an internal loop back which can be used for self-test
operation: the bit stream output of the transmitter is fed back to the receiver internally. The RxCAN
input pin is ignored and the TxCAN output goes to the recessive state (logic ‘1’). The MSCAN08
behaves as it does normally when transmitting and treats its own transmitted message as a message
received from a remote node. In this state the MSCAN08 ignores the bit sent during the ACK slot of
the CAN frame Acknowledge field to insure proper reception of its own message. Both transmit and
receive interrupt are generated.
1 = Activate loop back self-test mode
0 = Normal operation
WUPM — Wakeup Mode
This flag defines whether the integrated low-pass filter is applied to protect the MSCAN08 from
spurious wakeups (see 23.8.5 Programmable Wakeup Function).
1 = MSCAN08 will wake up the CPU only in cases of a dominant pulse on the bus which has a
length of at least t_wup.
0 = MSCAN08 will wake up 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 23.10 Clock System).
1 = The MSCAN08 clock source is CGMOUT (see Figure 23-7).
0 = The MSCAN08 clock source is CGMXCLK/2 (see Figure 23-7).
NOTE
The CMCR1 register can be written only if the SFTRES bit in the MSCAN08
module control register is set
MC68HC908AZ60A • MC68HC908AS60A • MC68HC908AS60E Data Sheet, Rev. 6
288
Freescale Semiconductor