Rainbow Electronics ATA5746 - Manual (Page 25)

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