TWL1110 Datasheet, PDF (23/37 Pages) Texas Instruments – VOICE-BAND AUDIO PROCESSOR VBAPE

TWL1110
VOICE-BAND AUDIO PROCESSOR (VBAP™)
PRINCIPLES OF OPERATION
SLWS103 – NOVEMBER 2000
receive operation (continued)
receive volume control
The values in the volume control PGA control registers provide volume control for the earphone. Volume control
gain is set from 0 dB to –18 dB in 2-dB steps through the I²C interface. The default RX volume control gain is
0 dB.
Table 5. RX Volume Control
BIT NAME
RV3
RV2
RV1
0
0
0
0
0
0
0
0
1
0
0
1
0
1
0
0
1
0
0
1
1
0
1
1
1
0
0
1
0
0
RELATIVE GAIN
RV0
MIN TYP MAX UNIT
0
– 0.2
0
0.2 dB
1
– 2.2
– 2 –1.8 dB
0
– 4.2
– 4 – 3.8 dB
1
– 6.2
– 6 – 5.8 dB
0
– 8.2
– 8 –7.8 dB
1
–10.2 –10 – 9.8 dB
0
–12.2 –12 –11.8 dB
1
–14.2 –14 –13.8 dB
0
–16.2 –16 –15.8 dB
1
–18.2 –18 –17.8 dB
earphone amplifier
The analog signal can be routed to either of two earphone amplifiers: one with a differential output (EAR1ON
and EAR1OP) capable of driving a 8-Ω load, or one with a single-ended output (EAR2O) capable of driving a
8-Ω load.
earphone mute function
Muting can be selected by setting bit 3 of the power control register through the I²C interface.
receive PCM data format
D Companded mode: 8 bits are received, the most significant (MSB) first.
D Linear mode: 15 bits are received, MSB first.
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