SAM3X8E Atmel Corporation, SAM3X8E Datasheet - Page 1219

• Manufacturer Part Number: SAM3X8E
• Manufacturer: Atmel Corporation

40.7.5
40.7.5.1
11057A–ATARM–17-Feb-12
11057A–ATARM–17-Feb-12
Low-power Mode
Enabling Low-power Mode
In Low-power Mode, the CAN controller cannot send or receive messages. All mailboxes are
inactive.
In Low-power Mode, the SLEEP signal in the CAN_SR register is set; otherwise, the WAKEUP
signal in the CAN_SR register is set. These two fields are exclusive except after a CAN control-
ler reset (WAKEUP and SLEEP are stuck at 0 after a reset). After power-up reset, the Low-
power Mode is disabled and the WAKEUP bit is set in the CAN_SR register only after detection
of 11 consecutive recessive bits on the bus.
A software application can enable Low-power Mode by setting the LPM bit in the CAN_MR
global register. The CAN controller enters Low-power Mode once all pending transmit messages
are sent.
When the CAN controller enters Low-power Mode, the SLEEP signal in the CAN_SR register is
set. Depending on the corresponding mask in the CAN_IMR register, an interrupt is generated
while SLEEP is set.
The SLEEP signal in the CAN_SR register is automatically cleared once WAKEUP is set. The
WAKEUP signal is automatically cleared once SLEEP is set.
Reception is disabled while the SLEEP signal is set to one in the CAN_SR register. It is impor-
tant to note that those messages with higher priority than the last message transmitted can be
received between the LPM command and entry in Low-power Mode.
Once in Low-power Mode, the CAN controller clock can be switched off by programming the
chip’s Power Management Controller (PMC). The CAN controller drains only the static current.
Error counters are disabled while the SLEEP signal is set to one.
Thus, to enter Low-power Mode, the software application must:
Now the CAN Controller clock can be disabled. This is done by programming the Power Man-
agement Controller (PMC).
– Set LPM field in the CAN_MR register
– Wait for SLEEP signal rising
SAM3X/A
SAM3X/A
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