at91sam9263 ATMEL Corporation, at91sam9263 Datasheet - Page 670

• Manufacturer Part Number: at91sam9263
• Description: At91 Arm Thumb Microcontrollers
• Manufacturer: ATMEL Corporation

37.6.5.1
Figure 37-8. Enabling Low-power Mode
37.6.5.2
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(CAN_MSR3)
(CAN_MSR1)
(CAN_MR)
(CAN_SR)
(CAN_SR)
CAN BUS
WAKEUP
CAN_TIM
SLEEP
MRDY
MRDY
LPM
AT91SAM9263 Preliminary
Enabling Low-power Mode
Disabling Low-power Mode
LPEN= 1
A software application can enable Low-power Mode by setting the LPM bit in the CAN_MR glo-
bal 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).
The CAN controller can be awake after detecting a CAN bus activity. Bus activity detection is
done by an external module that may be embedded in the chip. When it is notified of a CAN bus
activity, the software application disables Low-power Mode by programming the CAN controller.
To disable Low-power Mode, the software application must:
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– Set LPM field in the CAN_MR register
– Wait for SLEEP signal rising
Arbitration lost
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