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Ask_nfsk – Rainbow Electronics ATA5746 User Manual

Page 25

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25

4596A–RKE–05/06

ATA5745/ATA5746 [Preliminary]

7.

ASK_NFSK

The ASK_NFSK pin allows the microcontroller to rapidly switch the RF front end between
demodulation modes. A logic 1 on this pin selects ASK mode, and a logic 0 FSK mode. The time
to change modes (T

Startup_Sig_Proc

) depends on the bit rate range being selected (not current bit

rate range) and is given in

Table 5-4 on page 22

. This response time is specified for applications

that require an ASK preamble followed by FSK data (for typical TPM applications). During
T

Startup_Sig_Proc

, the level on pin DATA_OUT is low.

Figure 7-1.

ASK Preamble 2.4 Kbits/s followed by FSK Data 9.6 Kbits/s

RX

ASK_NFSK

DATA_OUT

Data valid BR3

Data valid BR0

BR0

BR1

ENABLE

T

Startup_Sig_Proc