MC68HC08GZ32 Datasheet, PDF (135/320 Pages) Freescale Semiconductor, Inc – Microcontrollers

Programmer’s Model of Control Registers
12.13.1 MSCAN08 Module Control Register 0
Address: $0500
Bit 7
6
Read: 0
0
Write:
5
4
3
2
1
0
SYNCH
SLPAK
TLNKEN
SLPRQ
Reset: 0
0
0
0
0
0
0
= Unimplemented
Figure 12-16. Module Control Register 0 (CMCR0)
Bit 0
SFTRES
1
SYNCH — Synchronized Status
This bit indicates whether the MSCAN08 is synchronized to the CAN bus and as such can participate
in the communication process.
1 = MSCAN08 synchronized to the CAN bus
0 = MSCAN08 not synchronized to the CAN bus
TLNKEN — Timer Enable
This flag is used to establish a link between the MSCAN08 and the on-chip timer (see 12.9 Timer Link).
1 = The MSCAN08 timer signal output is connected to the timer input.
0 = The port is connected to the timer input.
SLPAK — Sleep Mode Acknowledge
This flag indicates whether the MSCAN08 is in module internal sleep mode. It shall be used as a
handshake for the sleep mode request (see 12.8.1 MSCAN08 Sleep Mode). If the MSCAN08 detects
bus activity while in sleep mode, it clears the flag.
1 = Sleep – MSCAN08 in internal sleep mode
0 = Wakeup – MSCAN08 is not in sleep mode
SLPRQ — Sleep Request, Go to Internal Sleep Mode
This flag requests the MSCAN08 to go into an internal power-saving mode (see 12.8.1 MSCAN08
Sleep Mode).
1 = Sleep — The MSCAN08 will go into internal sleep mode.
0 = Wakeup — The MSCAN08 will function normally.
SFTRES — Soft Reset
When this bit is set by the CPU, the MSCAN08 immediately enters the soft reset state. Any ongoing
transmission or reception is aborted and synchronization to the bus is lost.
The following registers enter and stay in their hard reset state:
CMCR0, CRFLG, CRIER, CTFLG, and CTCR.
The registers CMCR1, CBTR0, CBTR1, CIDAC, CIDAR0–CIDAR3, and CIDMR0–CIDMR3 can only
be written by the CPU when the MSCAN08 is in soft reset state. The values of the error counters are
not affected by soft reset.
When this bit is cleared by the CPU, the MSCAN08 tries to synchronize to the CAN bus. If the
MSCAN08 is not in bus-off state, it will be synchronized after 11 recessive bits on the bus; if the
MSCAN08 is in bus-off state, it continues to wait for 128 occurrences of 11 recessive bits.
Clearing SFTRES and writing to other bits in CMCR0 must be in separate instructions.
1 = MSCAN08 in soft reset state
0 = Normal operation
MC68HC08GZ32 Data Sheet, Rev. 3
Freescale Semiconductor
135