MC68HC908AZ60 Datasheet, PDF (350/480 Pages) Motorola, Inc – HCMOS Microcontroller Unit

MSCAN Controller (MSCAN08)
recessive state. If RXF=1, the message can be read and RXF can be
cleared. Copying of RxGB into RxFG doesn’t take place while in Sleep
mode. It is possible to access the transmit buffers and to clear the TXE
flags. No message abort takes place while in Sleep mode.
The MSCAN08 leaves Sleep mode (wake-up) when:
• bus activity occurs or
• the MCU clears the SLPRQ bit or
• the MCU sets the SFTRES bit
MCU
or MSCAN08
MSCAN08 Running
SLPRQ = 0
SLPAK = 0
MCU
MSCAN08 Sleeping
SLPRQ = 1
SLPAK = 1
Sleep Request
SLPRQ = 1
SLPAK = 0
MSCAN08
Figure 6. Sleep Request/Acknowledge Cycle
NOTE: The MCU cannot clear the SLPRQ bit before the MSCAN08 is in Sleep
mode (SLPAK=1).
After wake-up, the MSCAN08 waits for 11 consecutive recessive bits to
synchronize to the bus. As a consequence, if the MSCAN08 is woken-up
by a CAN frame, this frame is not received. The receive message buffers
(RxFG and RxBG) contain messages if they were received before Sleep
mode was entered. All pending actions are executed upon wake-up:
copying of RxBG into RxFG, message aborts and message
MC68HC908AZ60 — Rev 2.0
348
MSCAN Controller (MSCAN08)
18-mscan
MOTOROLA