TLE8458Gx
Mode Control
5.2.1
Stand-By Mode
The Stand-By Mode is an idle operation mode, which disables the communication to the LIN bus. The TLE8458Gx
enters automatically the Stand-By Mode after a power-up. By setting the EN pin to HIGH, the operation mode
changes to Normal Operation Mode, regardless of the signal applied to the TxD pin.
The TLE8458Gx can be transferred to Stand-By mode by the following options:
•
•
•
•
After power - up on the supply
V
S
, the TLE8458Gx starts in Stand-By Mode.
From Sleep Mode or from Stop Mode the TLE8458Gx changes to Stand-By Mode if a Wake - Up event occurs
on the LIN bus.
From Sleep Mode or from Stop Mode the TLE8458Gx changes to Stand-By Mode if a Wake - Up event occurs
on the local Wake input WK.
In case of an under - voltage event on
V
S
, the TLE8458Gx changes to Stand-By Mode regardless of selected
operation mode.
In Stand-By mode the external power supply
V
CC
is active and LIN bus output stage is disabled. The TLE8458Gx
provides the following functionality in Stand-By Mode:
•
•
•
•
•
•
•
The power supply
V
CC
is active and functional.
The LIN transceiver output stage is disabled, no communication to the LIN bus is possible.
The LIN transceiver bus input receiver is disabled.
The LIN bus is terminated by the 30 kΩ.
Both digital pins, the TxD pin and the RxD pin act as output pins and indicate a Wake - Up or a Power - Up
event
.
The EN input pin is active. By setting the EN pin to HIGH the TLE8458Gx changes the operation mode to
Normal Operation Mode (see
The Wake - Up logic is disabled. Wake-Up events don’t trigger an operation mode change.
Logic table for Wake - Up monitoring
1)
Wake - Up event RxD
No
Via LIN Bus
Via WK Pin
HIGH
LOW
LOW
TxD
2)
LOW
HIGH
LOW
Comments
Power Up event
Wake - Up via LIN Bus
Wake - Up via local Wake pin WK
Table 6
Power - Up
Yes
No
No
1) The Wake - Up monitor is only active in Stand-By Mode
2) The TxD 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.
5.2.2
Normal Operation Mode
The TLE8458Gx enters the Normal Operation Mode after the microcontroller sets EN to “High” (see
In
Normal Operation mode the LIN bus receiver and the LIN bus transmitter are active. The TLE8458Gx converts the
logical HIGH and LOW signals on the TxD input pin to DOMINANT and RECESSIVE signals to the LIN bus.
Simultaneously the input receiver of the TLE8458Gx converts the DOMINANT and RECESSIVE signals on the LIN
bus to HIGH and LOW signals to the RxD output. In Normal Operation mode the output voltage
V
CC
is active and the
bus termination is set to 30 kΩ.
Normal Slope Mode and the Software Flash Mode are Normal Operation Modes. In these two sub-modes the
behavior of the power-supply
V
CC
and the bus termination are the same. Per default the TLE8458G always enters
into Normal Slope Mode, either from Sleep Mode, Stop Mode or from Stand-By Mode. The Software Flash Mode
can only be entered from Normal Slope mode.
In order to avoid any bus disturbance during a mode change, the output stage of the TLE8458Gx is disabled and
set to recessive state during the mode change procedure. To release the TLE8458Gx for data communication on
the LIN bus, the TxD pin needs to be set to HIGH for the time
t
torec
after the operation mode change.
Data Sheet
11
Rev. 1.01, 2009-04-28
INFINEON [ INFINEON TECHNOLOGIES AG ]
