NCV7381(2012) データシートの表示（PDF） - ON Semiconductor

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NCV7381
(Rev.:2012)

FlexRay® Bus Driver

ON Semiconductor 

NCV7381

Operating Mode Changes Caused by Internal Flags

Changes of some internal flags described in Table 3 can

force an operating mode transition complementing or

overruling the operating mode control by the digital inputs

STBN and EN which is shown in Figure 3:

• Setting the VBAT or VIO under−voltage flag causes a

transition to the Sleep mode

• Setting the VCC under−voltage flag, while the bus driver

is not in Sleep, causes a transition to the Standby mode

• Reset of the Under−voltage flag (i.e. recovery from

under−voltage) re−enables the control of the chip by

digital inputs STBN and EN.

• Setting of the Wake flag causes the reset of all

under−voltage flags and the NCV7381 transitions to the

Standby mode. The reset of the under−voltage flags

allows the external power supplies to stabilize properly

if, for example, they were previously switched off

during Sleep mode.

uBus

FlexRay Bus Driver

NCV7381 contains a fully−featured FlexRay bus driver

compliant with Electrical Physical Layer Specification Rev.

3.0.1. The transmitter part translates logical signals on

digital inputs TxEN, BGE and TxD into appropriate bus

levels on pins BP and BM. A transmission cannot be started

with Data_1. In case the transmitter is enabled for longer

than dBDTxActiveMax, the TxEN Timeout flag is set and the

current transmission is disabled. The receiver part monitors

bus pins BP and BM and signals the detected levels on digital

outputs RxD and RxEN. The different bus levels are defined

in Figure 5. The function of the bus driver and the related

digital pins in different operating modes is detailed in

Table 4 and Table 5.

• The transmitter can only be enabled if the activation of

the transmitter is initiated in Normal mode.

• The receiver function is enabled by entering a

normal−power mode.

BP

VCC/2

Idle_LP

Idle

Data_0

Figure 5. FlexRay Bus Signals

BM

Data_1

Table 4. TRANSMITTER FUNCTION AND TRANSMITTER−RELATED PINS

Operating Mode

BGE

TxEN

Standby, Go−to−sleep, Sleep

x

x

Receive−only

x

x

Normal

0

x

1

1

1

0

1

0

TxD

Transmitted Bus Signal

x

Idle_LP

x

Idle

x

Idle

x

Idle

0

Data_0

1

Data_1

Table 5. RECEIVER FUNCTION AND RECEIVER−RELATED PINS

Operating Mode

Signal on Bus

Standby, Go−to−sleep, Sleep

x

x

Normal,

Receive−only

Idle

Data_0

Data_1

Wake flag

not set

set

x

x

x

RxD

High

Low

High

Low

High

RxEN

High

Low

High

Low

Low

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