NCV7381B0V2GEVB
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3
Operating Modes
The nodes can operate in two different operating modes:
•Normal mode − all the nodes continuously
communicate over the FlexRay bus
•Sleep mode − the communication is suspended. Both
NCV7381B FlexRay transceivers are switched to
low−power Sleep operating mode. The VCC and VIO
power supplies are switched off by NCV7381B INH
output and the transceivers are powered from VBAT
supply input. MCU is not running and the board can be
only woken−up with one of the Local Wake−up
pushbutton switches (SW70, SW80). Indication LEDs
are switched off.
Enter Sleep Mode Sequence
A transition to Sleep mode can be initiated by the node
with address 1:
•Press and hold the Node1’s #IRQ pushbutton switch for
more than 5 seconds. The GO_TO_SLEEP signal is
transmitted over the FlexRay bus. All the nodes then
synchronously stop the communication and switch to
Sleep mode.
Wake−up Sequence
The network operating in Sleep mode can be woken−up
by any node:
•NCV7381B Local Wake−up function – Press the Local
Wake−up pushbutton switch on any node connected to
the network. The corresponding FlexRay transceiver is
woken−up from Sleep mode and activates its INH
output. Consequently the VCC and VIO supply voltage
regulators are activated and the MCU resumes
operation in Normal mode.
•NCV7381B Remote Wake−up function – Once the first
node is active, it automatically wakes up the rest of the
network by sending FlexRay Remote Wakeup Pattern
over the bus. As soon as all the nodes are woken−up
and initialized, the FlexRay communication is restarted.
LED Indication modes
Three LED indication modes are available – FlexRay
communication indication, Status indication
Channel A and B. Press and hold the pushbutton for
approximately 2 seconds to cycle between the indication
modes.
•FlexRay communication indication – each LED is
assigned to one slot according to LED number. The
LED is blinking if the respective slot in FlexRay
communication is active.
Figure 3. FlexRay communication indication
Slot 5 − Data transmitted
Slot 4 − Data transmitted
Slot 3 − Data transmitted
Slot 2 − Data transmitted
Slot 1 − Data transmitted
•FlexRay transceiver status indication − Channel A
•FlexRay transceiver status indication − Channel B
♦LED1 − Local Wake−Up status
♦LED2 − Remote Wake−up status
♦LED3 − TxEN Timeout status
♦LED4 − Bus Error status
♦LED5 − VIO Undervoltage status
♦LED6 − VCC Undervoltage status
♦LED7 − VBAT Undervoltage status
♦LED8 − Power−on status
Figure 4. FlexRay transceiver status indication
Power−on status
VBAT Undervoltage status
VCC Undervoltage status
VIO Undervoltage status
Bus Error status
TxEN Timeout status
Remote Wake−up status
Local Wake−up status
In FlexRay transceiver status indication mode, press the
pushbutton shortly to read−out the status register.
