mc9s12xd256 Freescale Semiconductor, Inc, mc9s12xd256 Datasheet - Page 468

• Manufacturer Part Number: mc9s12xd256
• Description: Hcs12x Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
10.4.5.1
As shown in
run mode.
10.4.5.2
The WAI instruction puts the MCU in a low power consumption stand-by mode. If the CSWAI bit is set,
additional power can be saved in power down mode because the CPU clocks are stopped. After leaving
this power down mode, the MSCAN restarts its internal controllers and enters normal mode again.
While the CPU is in wait mode, the MSCAN can be operated in normal mode and generate interrupts
(registers can be accessed via background debug mode). The MSCAN can also operate in any of the
low-power modes depending on the values of the SLPRQ/SLPAK and CSWAI bits as seen in
10.4.5.3
The STOP instruction puts the MCU in a low power consumption stand-by mode. In stop mode, the
MSCAN is set in power down mode regardless of the value of the SLPRQ/SLPAK and CSWAI bits
(Table
10.4.5.4
The CPU can request the MSCAN to enter this low power mode by asserting the SLPRQ bit in the
CANCTL0 register. The time when the MSCAN enters sleep mode depends on a fixed synchronization
delay and its current activity:
468
1
‘X’ means don’t care.
10-36).
CPU Mode
STOP
WAIT
RUN
Table
Operation in Run Mode
Operation in Wait Mode
Operation in Stop Mode
MSCAN Sleep Mode
10-36, only MSCAN sleep mode is available as low power option when the CPU is in
CSWAI = X
SLPRQ = 0
SLPRQ = 0
CSWAI = 0
SLPAK = 0
SLPAK = 0
Table 10-36. CPU vs. MSCAN Operating Modes
Normal
MC9S12XDP512 Data Sheet, Rev. 2.17
1
CSWAI = X
SLPRQ = 1
SLPRQ = 1
CSWAI = 0
SLPAK = 1
SLPAK = 1
Sleep
MSCAN Mode
Reduced Power Consumption
Power Down
SLPRQ = X
SLPRQ = X
CSWAI = X
CSWAI = 1
SLPAK = X
SLPAK = X
Freescale Semiconductor
SLPRQ = X
SLPRQ = X
SLPRQ = X
CSWAI = X
CSWAI = X
CSWAI = X
SLPAK = X
SLPAK = X
SLPAK = X
(CANE=0)
Disabled
Table
10-36.