Left ADC
CIC filter
Right ADC
CIC filter
Signal
Processing
Blocks
GPIO
MISO
DIN
SCLK
DIG_MIC_IN
DIG_MIC_CLK
To dig. mic
CLK
From dig.
mic DATA
Digital Microphone Input/Decimation Filter
2.3
Digital Microphone Input/Decimation Filter
The TLV320DAC3203 includes a stereo decimation filter for digital microphone inputs. The stereo
recording path can be powered up one channel at a time, to support the case where only mono record
capability is required.
The digital microphone input path of the TLV320DAC3203 features a large set of options for signal
conditioning as well as signal routing:
•
Stereo decimation filters (PDM input)
•
Fine gain adjustment of digital channels with 0.1 dB step size
•
Digital volume control with a range of -12 to +20dB
•
Mute function
In addition to the standard set of stereo decimation filter features the TLV320DAC3203 also offers the
following special functions:
•
Channel-to-channel phase adjustment
•
Adaptive filter mode
2.3.1 Digital Microphone Interface
The TLV320DAC3203 digital-microphone interface is shown in
.
Figure 2-6. Digital Microphone in TLV320DAC3203
The TLV320DAC3203 outputs internal clock DIG_MIC_CLK on GPIO pin ( Page 0, Register 51, D(5:2)) or
MISO pin (Page 0, Register 55, D(4:1)). 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 GPIO, DIN or
SCLK pins. Internally the TLV320DAC3203 latches the steady value of data on the rising edge of
DIG_MIC_CLK for the Left ADC channel, and the steady value of data on falling edge for the Right ADC
channel.
21
SLAU434 – May 2012
TLV320DAC3203 Application
Copyright © 2012, Texas Instruments Incorporated