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AS3931

Datasheet - Configuring the Product

9.5.1 M0 (Correlator Off)

Bit M0 is used to simultaneously turn off all 3 correlators. This is done by turning off the correlator clocks. This can be used to reduce power

consumption when the Direct Data Mode is used.

9.5.2 M1 (Single/Double Wake Pattern)

Bit M1 selects the number of data patterns that are necessary for wakeup detection.

9.5.3 M2, M3 (Zero-Half-Bit Detection Mode)

Bits M2 and M3 select the number of Zero-Half-bits that are allowed to be invalid. A high level of allowed invalid Zero-Half-bits increases the error

tolerance related to noise or interference’s, that means that the probability for the detection of a valid WAKE pattern increases. Note that in turn

the immunity against parasitic wakeups (WAKE detection when no data has been sent, due to noise or interference’s) is reduced.

9.5.4 M4 (Detector Time Constant)

Bit M4 is used to switch between a large and a small

τ of the detector threshold adoption filter. A large τ is recommended, because it increases

the noise margin. A small

τ can be used to improve the wake sensitivity when non-specified wake-patterns are used.

9.5.5 M5

Not used; must always be programmed to 0 by the user!

Table 24. M0 Bit Mode

M0

Mode

0Low RSSI step

1

High RSSI step

Table 25. M1 Bit Mode

M1

Mode

0

Single Data pattern

1

Double Data pattern

Table 26. M2, M3 Bit Mode

M2

M3

WAKE Pin Function

0

0

3 invalid Zero-bits allowed

1

0

2 invalid Zero-bits allowed

0

1

1 invalid Zero-bits allowed

1

1

0 invalid Zero-bits allowed

Table 27. M4 Bit Mode

M4

Mode

0

small

τ

1

large

τ