tda5251f1 Infineon Technologies Corporation, tda5251f1 Datasheet - Page 68

• Manufacturer Part Number: tda5251f1
• Description: Ask/fsk 315mhz Wireless Transceiver
• Manufacturer: Infineon Technologies Corporation

Confidential
This yields the following results:
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
TH2= 000000000001
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
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:
As an example a desired RSSI threshold voltage of 500mV results in TH3~26=011010 b , which has
to be written into D0 to D5 of the RSSI_TH3 register (sub address 08H).
Default value (RSSI detection inactive):
TH3=111111 b
3.8
ON= (2
OFF=( 2
f
Example: t
ON= 65535-(32300*0,005) ~ 65373= 1111111101011101
OFF= 65535-(32300*0,055) ~ 63758= 1111100100001110
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
RC
= Frequency of internal RC Oszillator
16
16
-1)-(f
-1)-(f
ON
RSSI threshold voltage - RF input power
Calculation of ON_TIME and OFF_TIME
= 0,005s, t
RC
RC
TH3
*t
*t
ON
OFF
=
)
b
b
desired
)
OFF
= 0,055s, f
TH1~ 738= 001011100010
TH2~ 902= 001110000110
RSSI
1.2V
threshold
RC
= 32300Hz
voltage
68
×
(
2
b
b
6
b
-
b
) 1
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TDA5251 F1
Version 1.0
Application
2003-02-18