TDA5240 Datasheet, PDF (115/284 Pages) Infineon Technologies AG – Enhanced Sensitivity Multi-Channel Quad-Configuration Receiver

TDA5240
Functional Description
pattern is missed. Therefore the Off time depends mainly on the duration of the expected
wake-up pattern.
If there are further channels scanned, T_OFF has to be reduced by the related additional
On times.
For basic timing of WU on RSSI in COO mode, please see Figure 81.
RF signal e.g . ASK
RX ON
SLEEP
Figure 81
t St art up
t t WULOT _WULOT
12
tON
COO Polling in WU on RSSI Mode
t
t
t t WULOT _{WULOT_part}
n-1 n_partially
last observation time
window is forced to end by
end of t_ON
latest decision here !
Always check at the end of the current observation time window, if there is a WU (Wake-
Up) event or NOT. This means, in algorithmic description (see also Figure 10,
Chapter 2.4.7 RSSI Peak Detector and Chapter 2.4.8.5 Wake-Up Generator):
if (RSSIPWU_value > x_WURSSITHy) and (RSSIPWU_value > x_WURSSIBHy)
then WU
else NOT
Here, ‘NOT‘ means to keep on evaluating and move on to the next observation time
window, also keep on peak value tracking of RSSIPWU signal. Keep on walking through
the observation time windows until there is a WU event from the algorithm above or
finally decide at the end of the On time with the following algorithm:
if (RSSIPWU_value > x_WURSSITHy) and (RSSIPWU_value < x_WURSSIBLy or
RSSIPWU_value > x_WURSSIBHy)
then WU
else NOT
If there is a WU event at the end of an observation time window while walking through
the observation time windows, freeze/hold this decision/peak value in register RSSIPWU
for optional read out and switch to run mode self polling.
Instead of the single RSSI criterion also the Signal Recognition criterion can be
activated.
Data Sheet
115
V4.0, 2010-02-19