MC68HC12 Datasheet, PDF (340/478 Pages) Motorola, Inc – The MC68HC912DT128A microcontroller unit (MCU) is a 16-bit device composed of standard on-chip peripherals including a 16-bit central processing unit

MSCAN Controller
NOTE: The MCU cannot clear the SLPRQ bit before the msCAN12 is in SLEEP
mode (SLPAK = 1).
After wake-up, the msCAN12 waits for 11 consecutive recessive bits to
synchronize to the bus. As a consequence, if the msCAN12 is woken-up
by a CAN frame, this frame will not be received. The receive message
buffers (RxBG and RxFG) will contain messages if they were received
before sleep mode was entered. Pending copying of RxBG and RxFG,
as well as pending message aborts and pending message
transmissions, will now be executed. If the msCAN12 is still in bus-off
state after sleep mode was left, it continues counting the 128*11
consecutive recessive bits.
MCU
or msCAN12
msCAN12 Running
SLPRQ = 0
SLPAK = 0
MCU
msCAN12 Sleeping
SLPRQ = 1
SLPAK = 1
SLEEP Request
SLPRQ = 1
SLPAK = 0
msCAN12
Figure 18-6. SLEEP Request / Acknowledge Cycle
Technical Data
340
MSCAN Controller
MC68HC912DT128A — Rev 4.0
MOTOROLA