TLE8458

Mode Control

Data Sheet

12

Rev. 1.1, 2014-04-01

In order to avoid any bus disturbance during a mode change, the output stage of the TLE8458 is disabled and set

to recessive state during the mode change procedure. To release the TLE8458 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.

5.2.2.1

Normal Slope Mode

In Normal Slope Mode the maximum data transmission rate of the LIN transceiver is limited by the slope control

mechanism of LIN output signal. The limitation of the slew rate of the LIN output signal results in an optimized

radiated emission fulfilling automotive EMC requirements.

The data transmission rate of the TLE8458G and the TLE8458GV33 is limited to 20 kBaud in Normal Operation

Mode and the devices are compliant to the specification LIN2.1.

5.2.2.2

Software Flash Mode

Software Flash Mode is a Normal Operation Mode and it is possible to transmit data to the LIN bus and receive

data from the LIN bus. The slope control mechanism of the LIN transmitter output stage is disabled and therefore

it is possible to reach higher data transmission rates, disregarding the EMC limitation of the LIN network. The

Software Flash Mode can be used for programming the external microcontroller via the LIN bus, got example

during the production flow of the ECU.

The Software Flash Mode can only be entered from Normal Slope Mode (see Figure 3). By setting the EN pin to

low for the time

t

fl1 and by generating a falling and a rising edge at the TxD pin with the time tfl2 and tfl3 during the

low phase of the EN pin, the TLE8458 changes to the Software Flash Mode (see Figure 5). Vice versa, the

TLE8458 changes from Software Flash Mode to Normal Slope Mode by applying the same sequence to the EN

pin and the TxD pin.

In any case, regardless if the device is in Normal Slope Mode or in Software Flash Mode, a LOW signal on the EN

pin changes the operation mode to Sleep Mode or Stop Mode. The slope control mechanism will be activated,

when the device changes to the Normal Operation Mode again.

Figure 5

Software Flash Mode

TO20070515.vsd

Normal

Mode

TxD

EN

t

fl3

t

fl1

Software

Flash Mode

t

fl2

t

fl3

t

fl3

t

fl1

t

fl2

t

fl3

Normal

Mode