L9788 datasheet(164/264 Pages) STMICROELECTRONICS

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LIN/K-LINE interface

L9788

164/264

DS12308 Rev 4

13.3

LIN thermal shut down

The LIN block has a dedicated thermal sensor to protect itself.

To protect LIN block from temperature overheat (high battery range of operation, soft short

conditions, etc.) a dedicated thermal sensor placed close to power mos is present in the

layout sensing FET temperature; one threshold is implemented (T_SD_H) with Hysteresis

(T_SD_hys). When the T_SD_H threshold is detected the Driver switches OFF. Once the

power stage has been switched-off for over-temperature detection, it will be able to switch

on again when temperature is decreased below thermal shut down threshold plus hysteresis

value to avoid high frequency on-off cycling.

13.4

LIN error handling

The Chip provides the following 3 error handling features which are not described in the

standard LIN Spec Rev2.1, but are realized in different stand alone LIN Interface /

microcontrollers to switch the application back to normal operation mode.

The error handling features can be disabled through the LIN_ERR_EN[2:0] (CONFIG-REG

11 D1~D3)bit.

13.4.1

LIN dominant TXD timeout

If TXDC is in dominant state (low) for t > t TXDC_DOM_TO=12ms(typ) the transmitter will

be disabled, status bit LIN_TXD_DOM (Upstream Bit Map Read15 frame 1) will be latched

and can be read and cleared by MSC. The transmitter remains disabled until the status

LIN_TX_DOM_ERR_CFG.

13.4.2

LIN permanent recessive

In case TXD changes to dominant (low level) state but RxD signal does not follow within

tLIN1: 40 us (typ), the transmitter is disabled. The status bit LIN_PERM_REC (Upstream Bit

Map Read15 frame 1) is latched and can be read and cleared by MSC. The transmitter

remains disabled until the status register is cleared.

13.4.3

LIN Permanent Dominant

In case the bus state is dominant (low level) for more than tLIN2: 12 ms (typ) a permanent

dominant status is detected. The status bit LIN_PERM_DOM (Upstream Bit Map Read15

frame 1) is latched and can be read and cleared by MSC. The transmitter is not switched off.

L9788 Datasheet(PDF) 164 Page - STMicroelectronics