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AS3930

Datasheet - Detailed Descr i p ti on

8.6 Wake-up Protocol - Carrier Frequency 125 kHz

8.6.1 Without Pattern Detection

Figure 17. Wake-up Protocol Overview without Pattern Detection (only carrier frequency detection)

In case the data correlation is disabled (R1<1>=0), the AS3930 wakes up upon detection of the carrier frequency only, as shown in Figure 17. In

order to ensure that AS3930 wakes up, the carrier burst has to last longer than 550 µs. There are two possibilities to set AS3930 back to

listening mode: either the microcontroller sends the direct command clear_wake via SDI, or the time out option is used (R7<7:5>). In case the

latter is chosen, then the AS3930 is automatically set to listening mode after the time defined in T_OUT (R7<7:5>), counting starts at the low-to-

high WAKE edge on the WAKE pin.

Carrier Burst

Data

Carrier Burst > 550 us

WAKE

Clear_wake

DAT