AS3930-BQFT austriamicrosystems, AS3930-BQFT Datasheet - Page 23

• Manufacturer Part Number: AS3930-BQFT
• Description: IC RF PROGRAM RECEIVER 16-QFN
• Manufacturer: austriamicrosystems

Specifications of AS3930-BQFT

• Rf Type: Read / Write
• Frequency: 110kHz ~ 150kHz
• Features: RSSI Equipped
• Package / Case: 16-VFQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: AS3930-BQFTTR

AS3930
Data Sheet - D e t a i l e d D e s c r i p t i o n
8.7 Wakeup Protocol - Carrier Frequency 125 kHz
8.7.1 Without pattern detection (Manchester decoder disabled)
Figure 17. Wakeup Protocol Overview without Pattern Detection (only carrier frequency detection, Manchester decoder disabled)
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. To set AS3930 back to listening mode there are two
possibilities: 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,AS3930is 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.
8.7.2 Single Pattern Detection (Manchester decoder disabled)
The
Figure 18
shows the wakeup protocol in case the pattern correlation is enabled (R1<1>=1) for a 125 kHz carrier frequency. The initial carrier
burst has to be longer than 550 µs and can last maximum 16 bits (see bit rate definition in
Table
18). If the ON/OFF mode is used (R1<5>=1), the
minimum value of the maximum carrier burst duration is limited to 10 ms. This is summarized in
Table
21. In case the carrier burst is too long the
internal wakeup will be set back to low and the false wakeup counter (R13<7:0>) will be incremented by one.
The carrier burst must be followed by a preamble (0101... modulated carrier with a bit duration defined in
Table
18) and the wakeup pattern
stored in the registers R5<7:0> and R6<7:0>. The preamble must have at least 4 bits and the preamble duration together with the pattern should
not be longer than 40 bits. If the wakeup pattern is correct the signal on the WAKE pin is set to high and the data transmission can get started. To
set the chip back to listening mode the direct command clear_false, as well as the time out option (R7<7:5>) can be used.
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