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[v1-08] 2015-Sep-02

AS3933 − Detailed Description

Wake-Up Protocol: Frequency Detection Only

Figure 50:

Wake-Up Protocol Overview Without Pattern Detection

In case the pattern correlation is disabled (R1<1>=0) the

AS3933 wakes up upon detection of the carrier frequency only

as shown in Figure 50. The minimum duration of the carrier

burst in order to ensure that AS3933 wakes up and the RSSI is

settled is specified in the Figure 52. In addition the carrier burst

does not have to be longer than 155 periods of the Clock

Generator (Crystal oscillator or RCO or External Clock). As shown

in the Figure 20, the AS3933 after the detection of the carrier

goes directly from the Listening mode to Data receiving mode

after settling the RSSI.

Wake-Up Protocol: Pattern Detection Enabled

In case the pattern correlation is enabled (R1<1>=1) the AS3933

generates a wake-up interrupt if the wake-up protocol is

fulfilled. The communication protocol consists of a carrier burst,

a preamble (0101010…. ON/OFF modulated carrier) and the

16-bit pattern. In case the double pattern option is enabled

(R1<2>=1) the 16-bit pattern has to be repeated 2 times

consequentially (2 times the same pattern). The signal on the

WAKE pin goes high one bit after the end of the pattern and the

data transmission can get started.

Carrier Burst

Data

Carrier Burst

WAKE

Clear_wake

DAT

AS3933 bảng dữ liệu(PDF) 45 Page - ams AG