TDA5235
Functional Description
Wake-Up on Signal Recognition
Instead of the previously mentioned RSSI criterion, the Signal Recognition criterion (see
Chapter 2.4.8.1) can be applied for Wake-Up search. So the x_SIGDET1, x_SIGDETLO
and x_NDTHRES threshold registers can be used.
The observation time has to be specified in the register x_WULOT. This observation time
has to contain the delay in the signal path (12.5 µs + 2.25*Tbit) and the duration for the
comparison of the Signal Recognition criterion.
The number of consecutive valid Signal Recognition samples/levels is compared vs. a
threshold defined in x_WURSSIBH1 register. Please note that x_WURSSIBH1 register
is used for both Wake-Up on RSSI and Wake-Up on Signal Recognition function. This
threshold has an influence on the false alarm rate. So x_WURSSIBH1 defines the
minimum needed consecutive T/16 samples of the Signal Recognition output to be at
high level for a positive Wake-Up event generation.
Wake-Up on Data Criterion
All SFRs configuring the Wake-up Generation Unit support the Multi-Configuration
capability. The search for a wake-up data criterion is started if symbol synchronization is
given within a certain duration (see Chapter 2.4.8.8 RUNIN, Synchronization Search
Time and Inter-Frame Time); otherwise the wake-up search is aborted. During the
observation period, the wake-up data search is aborted immediately if symbol
synchronization is lost. If this is not the case, the wake-up search will last for the number
of chips/bits defined in the register x_WUBCNT.
The Wake-up Window (WUW) Chip/Bit Counter counts the number of received chips/bits
and compares this number vs. the number of chips/bits defined in the register
x_WUBCNT.
The Code Violation Detector checks the incoming chip data stream for being Bi-Phase
coded. A Code Violation is given if three consecutive chips are ’One’ or ’Zero’.
The Bit Change Detector checks the incoming Bi-phase coded bit data stream for
changes from 'Zero' to 'One' or 'One' to 'Zero'.
The Pattern Detector searches for a pattern with 16 chips/bits length within the Wake-up
Window. The pattern is configurable via the registers x_WUPAT0 and x_WUPAT1.
On using Data Slicer Bit Mode, the Wake-up criteria Equal Bits Detection and Pattern
Detection cannot be applied. Further details can be seen at the end of Chapter 2.4.8.4.
The selection of 1 out of 4 wake-up data criteria is done via the x_WUC register.
Data Sheet
53
V1.0, 2010-02-19
INFINEON [ Infineon ]
