TDA5251F1 Datasheet, PDF (68/88 Pages) Infineon Technologies AG – ASK/FSK 315MHz Wireless Transceiver

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This yields the following results:
TH1~ 738= 001011100010_b
TH2~ 902= 001110000110_b
TDA5251 F1
Version 1.0
Application
which have to be programmed into the D0 to D11 bits of the COUNT_TH1 and COUNT_TH2
registers (subaddresses 06H and 07H), respectively.
Default values (window counter inactive):
TH1= 000000000000_b
TH2= 000000000001_b
Note: The timing window of +-10% of a given high time T in general does not correspond to a
frequency window +-10% of the calculated data frequency.
3.7.2 RSSI threshold voltage - RF input power
The RF input power level is corresponding to a certain RSSI voltage, which can be seen in Section
3.5. The threshold TH3 of this RSSI voltage can be calculated with the following formula:
TH3 = ^desired
RSSI threshold
1.2V
voltage _{× ( 2 6 - 1 )}
[3 – 39]
As an example a desired RSSI threshold voltage of 500mV results in TH3~26=011010b, which has
to be written into D0 to D5 of the RSSI_TH3 register (sub address 08H).
Default value (RSSI detection inactive):
TH3=111111b
3.8
Calculation of ON_TIME and OFF_TIME
ON= (2¹⁶-1)-(f_RC*t_ON)
OFF=( 2¹⁶-1)-(f_RC*t_OFF)
f_RC= Frequency of internal RC Oszillator
[3 – 40]
[3 – 41]
Example: t_ON= 0,005s, t_OFF= 0,055s, f_RC= 32300Hz
ON= 65535-(32300*0,005) ~ 65373= 1111111101011101_b
OFF= 65535-(32300*0,055) ~ 63758= 1111100100001110_b
The values have to be written into the D0 to D15 bits of the ON_TIME and OFF_TIME registers
(subaddresses 04H and 05H).
Preliminary Specification
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2003-02-18