L9669

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1.4 Diagnosis

A serial interface is available to retrieve diagnostic informations. Diagnostic data can be requested by using EN

as serial clock and evaluating NERR.

Figure 4.

Readout is initialized by a negative edge on EN and acknowledged by NERR entering HIGH state. Following

the next negative edge the first error status bit is displayed on NERR according to the data table below. If no

given by NSTB and EN with NERR showing bus errors or wake-up correspondingly. If the clock continues, the

readout sequence starts over again with the initial bit set HIGH.

The following errors are displayable (sequence listed in chronological order):

– error status bit 1 (LSB):

HIGH if Error 1 or 5

– error status bit 2:

HIGH if Error 2 or 9

– error status bit 3:

HIGH if Error 3

– error status bit 4:

HIGH if Error 4

– error status bit 5:

HIGH if Error 6

– error status bit 6:

HIGH if Error 8

– error status bit 7:

HIGH if Error 10

– error status bit 8:

HIGH if Thermal shutdown of Transceiver

1.5 Protections

A current limiting circuit protects the transmitter outputs against short-circuit to battery, ground and shorted

wires.

If the junction temperature exceeds a maximum value, the transmitter output stages are disabled.

99AT0004

E1

or E5

E2

or E9

E3

E4

EN

NERR

Mode

NSTB

Bus Error

detected

(Example)

Normal

RXonly

Standby

No Bus Errors

Delay between falling slope at EN and reaction at NERR: 0.7

µs...3.0 µs

(NERR is synchronized with internal clock).

t

Dmax

Diagnosis