lm4935rlx National Semiconductor Corporation, lm4935rlx Datasheet - Page 32

• Manufacturer Part Number: lm4935rlx
• Description: Audio Sub-system With Dual-mode Stereo Headphone And Mono High Efficiency Loudspeaker Amplifiers And Multi-purpose Adc
• Manufacturer: National Semiconductor Corporation

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Bits
12.0 Status & Control Registers
12.10 ADC_1 CONFIGURATION REGISTER
This register is used to control the LM4935’s audio ADC.
5:4
7:6
0
1
2
3
RIGHT_SELECT
ADC_SAMPLE_
LEFT_SELECT
MIC_SELECT
CPI_SELECT
HPF_MODE
RATE
Field
If set the microphone preamp output is added to the ADC input signal.
If set the cell phone input is added to the ADC input signal.
If set the left stereo bus is added to the ADC input signal.
If set the right stereo bus is added to the ADC input signal.
Programs the closest expected sample rate of the mono ADC, which is a variable required by the
AGC algorithm whenever the AGC is in use. This does not set the sample rate of the mono ADC.
Sets the HPF of the ADC
ADC_SAMPLE_RATE
HPF-MODE
00
01
10
00
01
10
11
11
TABLE 11. ADC_1 (0x06h)
2
2
2
2
2
2
2
2
(Continued)
32
Description
F
F
F
F
F
F
S
S
S
S
S
S
= 8 kHz, −0.5 dB
= 12 kHz, −0.5 dB
= 16 kHz, −0.5 dB
= 8 kHz, −0.5 dB
= 12 kHz, −0.5 dB
= 16 kHz, −0.5 dB
HPF Response
Sample Rate
@
@
No HPF
No HPF
12 kHz
16 kHz
24 kHz
@
@
@
@
8 kHz
300 Hz, Notch
150 Hz, Notch
450 Hz, Notch
600 Hz, Notch
225 Hz, Notch
300 Hz, Notch
@
@
@
@
@
@
55 Hz
27 Hz
82 Hz
110 Hz
41 Hz
55 Hz