K60P100M100SF2RM Datasheet, PDF (1383/1809 Pages) Freescale Semiconductor, Inc – K60 Sub-Family Reference Manual

• CPU removing the Doze Mode request
• CPU negating the DOZE bit of the MCR Register
• Self Wake mechanism
Chapter 48 CAN (FlexCAN)
In the Self Wake mechanism, if the SLF_WAK bit in MCR Register was set at the time
FlexCAN entered Doze Mode, then upon detection of a recessive to dominant transition
on the CAN bus, FlexCAN negates the DOZE bit, requests to resume its clocks and
negates the LPM_ACK after the CAN protocol engine recognizes the negation of the
Doze Mode request. It also sets the WAK_INT bit in the ESR Register and, if enabled by
the WAK_MSK bit in MCR, generates a Wake Up interrupt to the CPU. FlexCAN will
then wait for 11 consecutive recessive bits to synchronize to the CAN bus. As a
consequence, it will not receive the frame that woke it up. The following table details the
effect of SLF_WAK and WAK_MSK upon wake-up from Doze Mode.
Table 48-121. Wake-up from Doze Mode
SLF_WAK
0
0
1
1
1
1
WAK_INT
-
-
0
0
1
1
WAK_MSK
-
-
0
1
0
1
FlexCAN Clocks
Enabled
No
No
No
No
Yes
Yes
Wake-up Interrupt
Generated
No
No
No
No
No
Yes
48.4.9.4 Stop Mode
This is a system low power mode in which all MCU clocks can be stopped for maximum
power savings. The Stop Mode is globally requested by the CPU and the
acknowledgement is obtained through the assertion by the FlexCAN of a Stop
Acknowledgement signal. The CPU must only consider the FlexCAN in Stop Mode
when both request and acknowledgement conditions are satisfied.
If FlexCAN receives the global Stop Mode request during Freeze Mode, it sets the
LPM_ACK bit, negates the FRZ_ACK bit and then sends the Stop Acknowledge signal
to the CPU, in order to shut down the clocks globally. If Stop Mode is requested during
transmission or reception, FlexCAN does the following:
• Waits to be in either Idle or Bus Off state, or else waits for the third bit of
Intermission and checks it to be recessive
K60 Sub-Family Reference Manual, Rev. 6, Nov 2011
Freescale Semiconductor, Inc.
1383