mcf51ac256a Freescale Semiconductor, Inc, mcf51ac256a Datasheet - Page 359

• Manufacturer Part Number: mcf51ac256a
• Description: Mcf51ac Flexis
• Manufacturer: Freescale Semiconductor, Inc

in the CAN frame acknowledge field to ensure proper reception of its own message. Both transmit and
receive interrupts are generated.
15.5.5
If the MSCAN is disabled (CANE = 0), the MSCAN clocks are stopped for power saving.
If the MSCAN is enabled (CANE = 1), the MSCAN has two additional modes with reduced power
consumption, compared to normal mode: sleep and power down mode. In sleep mode, power consumption
is reduced by stopping all clocks except those to access the registers from the CPU side. In power down
mode, all clocks are stopped and no power is consumed.
Table 15-36
modes is entered by the given settings on the CSWAI and SLPRQ/SLPAK bits.
For all modes, an MSCAN wake-up interrupt can occur only if the MSCAN is in sleep mode (SLPRQ = 1
and SLPAK = 1), wake-up functionality is enabled (WUPE = 1), and the wake-up interrupt is enabled
(WUPIE = 1).
15.5.5.1
As shown in
run mode.
Freescale Semiconductor
1
2
‘X’ means don’t care.
For a safe wake up from Sleep mode, SLPRQ and SLPAK must be set to 1 before going into stop3 mode.
CPU Mode
Stop1 or 2
Stop3
Wait
Run
Low-Power Options
summarizes the combinations of MSCAN and CPU modes. A particular combination of
Table
Operation in Run Mode
15-36, only MSCAN sleep mode is available as low power option when the CPU is in
MCF51AC256 ColdFire Integrated Microcontroller Reference Manual, Rev. 5
CSWAI = X
SLPRQ = 0
SLPRQ = 0
CSWAI = 0
SLPAK = 0
SLPAK = 0
Table 15-36. CPU vs. MSCAN Operating Modes
Normal
1
CSWAI = X
SLPRQ = 1
SLPRQ = 1
SLPRQ = 1
CSWAI = X
CSWAI = 0
SLPAK = 1
SLPAK = 1
SLPAK = 1
Sleep
MSCAN Mode
2
Reduced Power Consumption
Power Down
Freescale’s Controller Area Network (MSCANV1)
SLPRQ = X
SLPRQ = X
CSWAI = X
SLPRQ = 0
CSWAI = X
CSWAI = 1
SLPAK = X
SLPAK = X
SLPAK = 0
SLPRQ = X
SLPRQ = X
SLPRQ = X
SLPRQ = X
CSWAI = X
SLPAK = X
CSWAI = X
SLPAK = X
CSWAI = X
SLPAK = X
CSWAI = X
SLPAK = X
(CANE=0)
Disabled
15-43