Datasheet

TLE7269G
Functional Description
Data Sheet 12 Rev. 1.2, 2007-11-13
4.3 Stand-By Mode
The Stand-By mode is entered automatically after:
• A Power-Up event on the supply
V
S
.
• A bus Wake-Up event on pin BUS1 or pin BUS2.
• A local Wake-Up event on the pin WK.
• A power on reset caused by power supply
V
S
or by the power supply V
IO
• In Stand-By mode the Wake-Up sources are monitored by the TxD1, RxD1 and RxD2 pins.
In Stand-By mode no communication on the LIN Bus is possible. The output stages are disabled and the LIN Bus
termination remains activated on both integrated transceivers. Only the RxD1, RxD2 and the TxD1 pin are used
to indicate the Wake-Up source. The TxD2 pin remains inactive. The RxD1 pin remains “Low” after a local Wake-
Up event on the pin WK and a bus Wake-Up event on either the bus 1 or the bus 2. The RxD2 pin remains “Low”
only after a bus Wake-Up event on the bus 2. A Power-Up event is indicated by a logical “High” on the RxD1 pin.
The signal on the TxD1 pin indicates the Wake-Up source, a weak pull-down signals a bus Wake-Up event on the
bus 1 and bus 2 and a strong pull-down signals a local Wake-Up event caused by the WK pin (see Table 2 and
Table 3). In order to detect a Wake-Up event via the TxD1 pin, the external microcontroller output needs to provide
a logical “High” signal. The Wake-Up flags indicating the Wake-Up source on the pins TxD1, RxD1 and RxD2 are
reset by changing the operation mode to Normal Operation mode.
The signal on the EN pin remains “Low” due to an internal pull-down resistor. Setting the EN pin to “High”, by the
microcontroller returns the TLE7269G to Normal Operation mode. In Stand-By mode the INH1 and INH2 outputs
are switching to
V
S
. The INH outputs can be used to control external device like a voltage regulator.
Table 3 Logic table for wake up monitoring
Inputs Outputs
power up WK BUS1 BUS2 RxD1
1)
1) To indicate the Wake-Up or Power-Up event on the RxD pin, the supply V
IO
has to be present
RxD2
1)
TxD1
2)
2) The TxD1 input needs an external termination to indicate a “High” or a “Low” signal. The external termination could be a
pull-up resistor or an active microcontroller output.
Remarks
Yes 1 1 1 1 1 1 No Wake-Up, Power-Up event
No Wake-
Up
3)
3) A local Wake-Up event is considered after a low signal on the pin WK (see Chapter 4.8).
1 1 0 1 0 Wake via wake pin
No 1 Wake-
Up
4)
1 0 1 1 Wake via BUS1
No 1 1 Wake-
Up
4)
4) A bus Wake-Up event is considered after the low to high transition on the bus (see Chapter 4.7).
Note: In the case of a sequence of Wake-Up events only the first Wake-Up event will be monitored on TxD1, RxD1
and RxD2. Subsequent Wake-Up events are ignored.
0 0 1 Wake via BUS2