TDA5150 Datasheet, PDF (30/106 Pages) Infineon Technologies AG – On-chip, high resolution fractional-N synthesizer and Sigma-Delta modulator with ASK, FSK, GFSK options

TDA 5150
TDA 5150 Functional Description
The feedback branches within the PRBS9 generator are fixed (as shown above), but the
PRBS generation can be influenced by SFR configuration in the following manner:
• A start value for the PRBS9 Generator can be programmed in SFR PRBS Start Value
(0x08). The reset value is 0xAB (10101011). Choice of 0x00 as start value is not
allowed, because the output of PRBS9 Generator should “lock” and will never go in
High. The PRBS Start Value is loaded into the PRBS9 Generator at the start of each
transmission.
• If the Data Scrambler is used, the start of scrambling can be configured in SFR
ENCCNT (0x27). If ENCCNT is 0, already the first bit is XOR’ed with PRBS9. If for
example ENCCNT = 0x10, the first 16 bits stay unscrambled. This is necessary if a
data frame should have always the same wake up and synchronization part, but the
payload should be pseudo-random for sensitivity measurements or to enhance the
clock recovery on the receiver side.
Data Sheet
30
V 1.0, July 2009