TLE7259-2GU Datasheet, PDF (11/31 Pages) Infineon Technologies AG – LIN Transceiver

Low Slope
Mode
EN
t_fl1
Flash Mode
TLE7259-2GU
Functional Description
Low Slope
Mode
t_fl1
TxD
t_fl2
t_fl3
Data transmission
t_fl4
t_torec
t_fl2
t_fl3
Data transm.
t_fl4
t_torec
Figure 6 Timing to enter Flash Mode
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 BUS.
• A local Wake-Up event on the pin WK.
• A power on reset caused by power supply V_S
• In Stand-By mode the Wake-Up sources are monitored by the TxD and RxD pins.
In Stand-By mode no communication on the LIN Bus is possible. The output stage is disabled and the LIN Bus
termination remains activated. The RxD and the TxD pin are used to indicate the Wake-Up source or a Power-Up
event. The RxD pin remains “Low“after a local Wake-Up event on the pin WK and a bus Wake-Up event on the
LIN bus. A Power-Up event is indicated by a logical “High“ on the RxD pin. The signal on the TxD pin indicates the
Wake-Up source, a weak pull-down signals a bus Wake-Up event on the LIN bus and a strong pull-down signals
a local Wake-Up event caused by the WK pin (see Table 1 and Table 2). In order to detect a Wake-Up event via
the TxD pin, the external microcontroller output needs to provide a logical “High” signal. The Wake-Up flags
indicating the Wake-Up source on the pins TxD and RxD 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 TLE7259-2GU to Normal Operation mode. In Stand-By mode the INH output is
switching to V_S. The INH output can be used to control external device like a voltage regulator.
Table 2 Logic table for wake up monitoring
power up WK BUS
RxD¹⁾ TxD²⁾ Remarks
Yes
1
1
1
1
No Wake-Up, Power-Up event
No
Wake- 1
0
0
Wake via wake pin
Up³⁾
No
1
Wake- 0
1
Wake via BUS
Up⁴⁾
1) To indicate the Wake-Up sources via the RxD pin a pull-up resistor to the external microcontroller supply is required.
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.
3) A local Wake-Up event is considered after a low signal on the pin WK (see Chapter 4.7).
4) A bus Wake-Up event is considered after a low to high transition on the LIN bus (see Chapter 4.6)
Data Sheet
11
Rev. 1.1, 2008-07-14