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Chapter 16
CAN Controller
User’s Manual U16504EE1V1UD00
16.17 Influence of the standby Function of the CAN Controller
16.17.1 CPU Halt Mode
The CPU halt mode is possible in conjunction with DCAN Sleep mode.
16.17.2 CPU Stop Mode
The DCAN stops any activity when its clock supply stops due to a CPU Stop mode issued. This may
cause an erroneous behaviour on the CAN bus. Entering the CPU Stop Mode is not allowed when the
DCAN is in normal mode, i.e. online to the CAN bus.
The DCAN will reach an overrun condition, when it receives clock supply again.
CPU Stop mode is possible when the DCAN was set to initialization state, sleep mode or stop mode
beforehand. Note that the CPU will not be started again if the DCAN Stop mode was entered previously.
16.17.3 DCAN Sleep Mode
The DCAN Sleep mode is intended to lower the power consumption during phases where no communi-
cation is required.
The CPU requests the DCAN Sleep mode. The DCAN will signal with the WAKE bit, if the request was
granted or if it is not possible to enter the sleep mode due to ongoing bus activities.
After a successful switch to the DCAN Sleep mode, the CPU can safely go into halt, watch or stop
mode. However, the application needs to be prepared that the DCAN cancels the sleep mode any time
due to bus activities. If the wake-up interrupt is serviced, the CPU Stop mode has not to be issued.
Otherwise the CPU will not be released from CPU Stop mode even when there is ongoing bus activity.
The wake-up is independent from the clock. The release time for the CPU Stop mode of the device is of
no concern because the DCAN synchronizes again to the CAN bus after clock supply has started.