UJA1075TWSLASH5V0SLASHWD datasheet(25/53 Pages) NXP

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UJA1075_2

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Product data sheet

Rev. 02 — 27 May 2010

25 of 53

NXP Semiconductors

UJA1075

High-speed CAN/LIN core system basis chip

6.8.1 LIN operating modes

6.8.1.1

Active mode

The LIN transceiver will be in Active mode when:

• the SBC is in Normal mode (MC = 10 or 11) and

• the transceiver is enabled (STBCL = 0; see Table 6) and

• the battery voltage (VBAT) is above the LIN undervoltage recovery threshold, Vuvr(LIN).

In LIN Active mode, the transceiver can transmit and receive data via the LIN bus pin.

The receiver detects data streams on the LIN bus pin (LIN) and transfers them to the

microcontroller via pin RXDL (see Figure 1) - LIN recessive is represented by a HIGH

level on RXDL, LIN dominant by a LOW level.

The transmit data streams of the protocol controller at the TXDL input (pin TXDL) are

converted by the transmitter into bus signals with optimized slew rate and wave shaping to

minimize EME.

6.8.1.2

Lowpower/Off modes

The LIN transceiver will be in Lowpower mode with bus wake-up detection enabled if bit

STBCL = 1 (see Table 6). The LIN transceiver can be woken up remotely via pin LIN in

Lowpower mode.

When the SBC is in Standby mode or Sleep mode (MC = 00 or 01), the LIN transceiver

will be in Off mode if bit STBCL = 0. The LIN transceiver is powered down completely in

Off mode to minimize quiescent current consumption.

Filters at the receiver inputs prevent unwanted wake-up events due to automotive

transients or EMI.

The wake-up event must remain valid for at least the minimum dominant bus time for

wake-up of the LIN transceiver, twake(busdom)min (see Table 11).

6.8.2 Fail-safe features

6.8.2.1

General fail-safe features

The following fail-safe features have been implemented:

• Pin TXDL has an internal pull-up towards VV1 to guarantee a safe, defined state if this

pin is left floating

• The current of the transmitter output stage is limited in order to protect the transmitter

against short circuits to pin BAT

• A loss of power (pins BAT and GND) has no impact on the bus lines or on the

microcontroller. There will be no reverse currents from the bus.

6.8.2.2

TXDL dominant time-out function

A TXDL dominant time-out timer circuit prevents the bus lines being driven to a permanent

dominant state (blocking all network communications) if TXDL is forced permanently LOW

by a hardware and/or software application failure. The timer is triggered by a negative

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