Datasheet

MonoData NoData MonoData NoData MonoData NoData

ADC_MOD_CLK

DIG_MIC_IN

Mono ADC

CIC Filter

Signal

Processing

Blocks

GPIO1

SDIN

ADC_MOD_CLK

DIG_MIC_IN

DOUT

D S-

ADC

TLV320AIC3100

SLAS667A –NOVEMBER 2009–REVISED MAY 2012

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Figure 5-17. Digital Microphone in the TLV320AIC3100

The TLV320AIC3100 outputs internal clock ADC_MOD_CLK on the GPIO1 pin (page 0 / register 51,

bits D5–D2 = 1010). This clock can be connected to the external digital microphone device. The single-bit

output of the external digital microphone device can be connected to the DIN pin. Internally, the

TLV320AIC3100 latches the steady value of the mono ADC data on the rising edge of ADC_MOD_CLK.

Figure 5-18. Timing Diagram for Digital Microphone Interface

When the digital microphone mode is enabled, the analog section of the ADC can be powered down and

bypassed for power efficiency. The AOSR value for the ADC channel must be configured to select the

desired decimation ratio to be achieved, based on the external digital microphone properties.

5.4.7 DC Measurement

The TLV320AIC3100 supports a highly flexible dc-measurement mode using the high-resolution

oversampling and noise-shaping ADC. This mode can be used when the ADC channel is not used for the

voice/audio record function. This mode can be enabled by programming page 0 / register 102, bit D7. The

converted data is 24 bits, using the 2.22 numbering format. The value of the converted data for the ADC

channel can be read back from page 0 / register 104 through page 1 / register 106. Before reading back

the converted data, page 0 / register 103, bit D6 must be programmed to 1 in order to latch the converted

data into the readback registers. After the converted data is read back, page 0 / register 103, bit D6 must

be immediately reset to 0. In dc-measurement mode, two measurement modes are supported.

Mode A

In dc-measurement mode A, a variable-length averaging filter is used. The length of averaging filter D can

be programmed from 1 to 20 by programming page 0 / register 102, bits D4–D0. To choose mode A,

page 0 / register 102, bit D5 must be programmed to 0.

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