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4.5 Audio Interface Tab
TLV320AIC34EVM Software
Figure 6. Audio Interface Tab
The Audio Interface tab (Figure 6 ) allows configuration of the audio digital data interface to the
TLV320AIC34.
The interface mode may be selected using the Transfer Mode control—selecting either I
2
S mode, DSP
mode, or Right- or Left-Justified modes. Word length can be selected using the Word Length control, and
the bit clock rate can also be selected using the Bit Clock rate control. The Data Word Offset, used in
TDM mode (see the product data sheet ) can also be selected on this tab.
Along the bottom of this tab are controls for choosing the BLCK and WCLK as being either inputs or
outputs. With the codec configured in Slave mode, both the BCLK and WCLK are set to inputs. If the
codec is in Master mode, then BCLK and WCLK are configured as outputs. Additionally, two buttons
provide the options for 3-stating the DOUT line when there is not valid data and transmitting BLCK and
WCLK when the codec is powered down.
Re-sync of the audio bus is enabled using the controls in the lower right corner of this screen. Re-sync is
done if the group delay changes by more than ± FS/4 for the ADC or DAC sample rates (see the
TLV320AIC34 data sheet). The channels can be soft muted when doing the re-sync if the Soft Mute
button is enabled.
In the upper right corner of this tab is the Digital Mic Functionality control. The TLV320AIC34 can accept
a data stream from a digital microphone, which would have its clock pin connected to the TLV320AIC34
GPIO1 pin, and the mic data connected to the GPIO2 pin. Once the digital microphone functionality is
enabled, the Digital Mic/ADC Selection selection allows the user to choose if one or two digital
microphones are connected to the codec. If only one digital microphone is connected, then the remaining
ADC can be used with an analog input signal from the analog input pins. Refer to section Section 4.7 for a
discussion of setting the GPIO pin options. The TLV320AIC34 can provide a modulator clock to the digital
microphone with oversampling ratios (OSR) of 128, 64, or 32. For a detailed discussion of how to connect
a digital microphone, refer to the application note Using the Digital Microphone Function on
TLV320AIC33EVM with AIC33EVM/USB-MODEVM System (literature number SLAA275 ), available for
download at www.ti.com .
The default mode for the EVM is configured as 44.1kHz, 16-bit, I
2
words, and the codec is a slave (BCLK
and WCLK are supplied to the codec externally). For use with the PC software and the USB-MODEVM,
the default settings should be used; no change to the software are required.
SLAU232 – December 2007 TLV320AIC34EVM-K 15
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