Silicon Laboratories Si4700, Руководство по программированию

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AN332
36 Confidential Rev. 0.2
Property 0x2104. TX_LINE_INPUT_LEVEL
Sets the input resistance and maximum audio input level for the LIN/RIN pins. An application providing a 150 mV
PK
input to the device on RIN/LIN would set Line Attenuation = 00, resulting in a maximum permissible input level of
190 mV
PK
on LIN/RIN and an input resistance of 396 k
Ω
. The Line Level would be set to 150 mV to correspond to
the TX audio deviation level set by the TX_AUDIO_DEVIATION property. An application providing a 1 V
PK
input to
the device on RIN/LIN would set Line Attenuation = 11, resulting in a maximum permissible input level of 636 mV
PK
on LIN/RIN and an input resistance of 60 k
Ω
. An external series resistor on LIN and RIN inputs of 40 k
Ω
would
create a resistive voltage divider that would keep the maximum line level on RIN/LIN below 636 mV
PK
. The Line
Level would be set to 636 mV
PK
to correspond to the TX audio deviation level set by the TX_AUDIO_DEVIATION
property. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may
only be set or read when in powerup mode. The default input level and peak line level is 636 mV
PK
with an input
impedance of 60 k
Ω
.
Default: 0x327C
Bit D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
Name
0 0 LIATTEN[1:0] 0 0 LILEVEL[9:0]
Bit Name Function
15:14 Reserved Always write to 0.
13:12 LIATTEN[1:0]
Line Attenuation.
00 = Max input level = 190 mV
PK
; input resistance = 396 k
Ω
01 = Max input level = 301 mV
PK
; input resistance = 100 k
Ω
10 = Max input level = 416 mV
PK
; input resistance = 74 k
Ω
11 = Max input level = 636 mV
PK
; input resistance = 60 k
Ω
(default)
11:10 Reserved Always write to 0.
9:0 LILEVEL[9:0]
Line Level.
Maximum line amplitude level on the LIN/RIN pins in mV
PK
. The default is 0x27C or
636 mV
PK
.