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Long reset:

This reset means a total reset of the analogue as well as for the digital part of the IC.

The output is forced to its default state (“high”). This condition remains for less than

1ms. After this time the IC is assumed to run in a stable condition and enters the initial

mode where the output represents the state of the target wheel (PROM value).

The following conditions lead to a long reset:

• Power-on condition.

• Low supply voltage: drop of the supply voltage to values less than 2.4V for a time

longer than 1µs .. 2µs or drop of the supply voltage to values less than 2.0V.

Short reset:

This reset means a reset of the digital circuitry. The output memorizes the state he had

before the reset. This condition remains for approx. 1µs. After that time the chip is

brought into the initial mode (output stays “high” for approx. 200µs for an untrimmed IC).

Then the output is released again and represents the state of the target wheel (PROM

value). The following conditions lead to a short reset:

• Watchdog overflow: If there is no switching at the output for more than 12 seconds.

• If there are four min- or max-events found without a switching event at the output

Software reset:

This reset can be performed in the testmode through the serial-interface. The IC output

is then used as data output for the serial interface.

The following condition lead to a software reset:

• There is a reset applied through the serial Interface

Table 1 shows an overview over the behaviour of the output under certain conditions.

Unprogrammed

Programmed

Noninverted

inverted

Noninverted

Inverted

output hold mode

-

long reset

High

-

High

High

short reset

High

-

normal TPO

inverted TPO

initial mode

high (self

calibration)

-

normal TPO

inverted TPO

precalibrated mode

Normal

-

Normal

Inverted

calibrated mode

Normal

-

Normal

Inverted

… state of output before a reset occurs

normal TPO … “low” if B

inverted TPO … “high” if B

normal

… “low” if B

inverted

… “high” if B

Table1: Output behaviour under certain conditions