MC68HC08AZ0 Datasheet, PDF (370/444 Pages) Motorola, Inc – Advance Information

Freescale Semiconductor, Inc.
msCAN08 Controller (msCAN08)
msCAN08 internal
sleep mode
The CPU can request the msCAN08 to enter the low-power mode by
asserting the SLPRQ bit in the Module Configuration Register (see
Figure 6). The time when the msCAN08 will then enter Sleep Mode
depends on its current activity:
• if it is transmitting, it will continue to transmit until there is no more
message to be transmitted, and then go into Sleep Mode
• if it is receiving, it will wait for the end of this message and then go
into Sleep Mode
• if it is neither transmitting or receiving, it will immediately go into
Sleep Mode
The application software must avoid to set up a transmission (by clearing
one or more TXE flag(s)) and immediately request Sleep Mode (by
setting SLPRQ). It will then depend on the exact sequence of operations
whether the msCAn will start transmitting or go into Sleep Mode directly.
During Sleep Mode the SLPAK flag is set. The application software
should use this flag as a handshake indication for the request to go into
Sleep mode.When in sleep mode the msCAN08 stops its own clocks
and the TxCAN pin will stay in recessive state.
The msCAN08 will leave sleep mode (wake-up) when bus activity occurs
or when the MCU clears the SLPRQ bit.
NOTE: The MCU can not clear the SLPRQ bit before the msCAN08 is in Sleep
Mode (SLPAK = 1).
MC68HC08AZ0
368
msCAN08 Controller (msCAN08)
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18-can
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