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23.4.3 Error Interrupts
The events PER, BOff and EWarn (monitored in
interrupt group can be enabled by setting bit EIE in
routed to interrupt line CAN0INT which has to be enabled by setting IE0 in this register.
23.5 Global Power-down Mode
The Concerto™ architecture supports a centralized global power-down control over the peripheral
modules through the SLEEP and DEEP SLEEP modes present in the System Control peripheral.
23.5.1 Entering Global Power-down Mode
The global power down mode for the CAN is requested by configuring the appropriate bits in the sleep
mode clock gating control(SCGC) or deep sleep mode clock gating Control(DCGC) register and enabled
either of these modes (SLEEP or DEEP SLEEP).
The CAN then finishes all transmit requests of the message objects. When all requests are done, the CAN
waits until a bus idle state is recognized. Then it will automatically set the Init bit to indicate that the global
power-down mode has been entered.
23.5.2 Wakeup from Global Power-down Mode
If the CAN module is in global power-down mode, a CAN bus activity detection circuit is active. On
occurrence of a dominant CAN bus level, the CAN will set the WakeUpPnd bit in Error and Status register
(see
Section
23.15.2).
If status interrupts are enabled, also an interrupt will be generated. This interrupt could be used by the
application to wakeup the CAN. For this, the application needs to clear the Init bit in CAN Control register.
After the Init bit has been cleared, the CAN module waits until it detects 11 consecutive recessive bits on
the CAN_RX pin and then goes bus-active again.
NOTE: The CAN transceiver circuit has to stay active during CAN bus activity detection. The first
CAN message, which initiates the bus activity, cannot be received. This means that the first
message received in power down mode is lost.
23.6 Local Power-down Mode
Besides from the centralized power-down mechanism controlled by the system control module, the CAN
supports a local power-down mode which can be controlled within the DCAN control registers.
23.6.1 Entering Local Power-down Mode
The local power down mode is requested by setting the PDR bit in CAN Control register.
The CAN then finishes all transmit requests of the message objects. When all requests are done, CAN
waits until a bus idle state is recognized. Then it will automatically set the Init bit in CAN Control register to
prevent any further CAN transfers, and it will also set the PDA bit in CAN Error and Status register. With
setting the PDA bits, the CAN module indicates that the local power down mode has been entered.
During local power down mode, the internal clocks of the CAN module are turned off, but there is a wake
up logic which can be active, if enabled. Also the actual contents of the control registers can be read back.
23.6.2 Wakeup from Local Power-down Mode
There are two ways to wake up the CAN from local power down mode:
1. The application could wake up the CAN module manually by clearing the PDR bit and then clearing the
Init bit in CAN Control register
2. A CAN bus activity detection circuit can be activated by setting the wake up on bus activity bit (WUBA)
in CAN Control register.
SPRUH22I – April 2012 – Revised November 2019
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23.15.2) , belong to the error interrupts. The error
23.15.1). Also,error interrupts can only be
M3 Controller Area Network (CAN)
Interrupt Functionality
1521
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