TDA5225 Datasheet, PDF (64/176 Pages) Infineon Technologies AG – Enhanced Sensitivity Multi-Channel Quad-Configuration Receiver

TDA5225
Functional Description
2.6.1.6 Automatic Modulation Switching
In Self Polling Mode, the chip is able to automatically change the type of modulation
after a wake-up criterion was fulfilled in a received data stream. The type of modulation
used in the different operational modes is selected by the SFR control bit MT.
2.6.1.7 Multi-Channel in Self Polling Mode
As previously mentioned, in Self Polling Mode the TDA5225 allows RF scans on up to
three RF channels per configuration, this can be defined in the x_CHCFG register.
Channel frequencies are defined in registers x_PLLINTCy, x_PLLFRAC0Cy,
x_PLLFRAC1Cy, x_PLLFRAC2Cy, where x = A, B, C or D and y = 1, 2 or 3.
The channel number at which a wake-up criterion has been found is available in register
RFPLLACC. See also Chapter 2.4.5 Sigma-Delta Fractional-N PLL Block.
2.6.1.8 Run Mode Self Polling (RMSP)
Wake-Up criterion fulfillment in Self Polling Mode for RSSI leads to a change to Run
Mode Self Polling and a transparent data stream can be processed externally by the
Application Controller (see Chapter 2.5.1.2 Data Interface).
Modulation switching is performed automatically, depending on register settings (see
Chapter 2.6.1.6 Automatic Modulation Switching)
Depending on interrupt masking, the host microcontroller is alerted when the level
criterion RSSI is fulfilled. See also Chapter 2.5.3 Interrupt Generation Unit
Run Mode Self Polling is left, when the timeout timer command “EXTTOTIM” is sent by
the Application Controller, or when an “EXTEOM found” command is sent by the
microcontroller and the SFR bit EOM2SPM is activated, or when the operating mode is
switched to SLEEP or Run Mode Slave by the host microcontroller.
When the TDA5225 gets the “EXTTOTIM” command, the receiver proceeds with Self
Polling Mode and with searching for a suitable wake-up criterion on the next
programmed channel (either next RF channel or next configuration, depending on the
selected mode - Multi-Configuration or Multi-Channel or a mix of both) or a search for a
wake-up criterion in Configuration A is initiated.
As long as the chip is in Run Mode Self Polling, the transparent data stream can be
processed externally by the Application Controller.
After an EOM was found, the information about the RF channel and the configuration of
the actual payload data is saved in the RFPLLACC register.
After receiving the “EXTEOM found” command the TDA5225 can either proceed with a
search for a wake-up criterion in the next configuration or a search for wake-up in
Data Sheet
64
V1.0, 2010-02-19