Analog Devices EVAL-ADAU1772Z, User Manual

Page: 12 / 29

Evaluation Board User Guide UG-477
Rev. A | Page 11 of 28
Stereo Line Input
The stereo input jack, J22, accepts a standard stereo TRS 1/8-inch
mini-plug (tip = left, ring = right) with two channels of audio.
Digital Microphones
PDM digital microphones can be connected to standard 0.100”
headers (J6 and J7). For example, the Analog Devices
ADMP521
digital microphone on the ADMP521Z evaluation board plugs
directly into the header.
To use the digital microphone headers on the
EVAL-ADAU1772Z ,
ensure that the proper settings have been made in SigmaStudio.
Navigate to the
Pin/Pad Control tab in the Hardware
Configuration/ADAU1772 Register Control section. Change
the value of the CLKOUT/ADC_SDATA1/MP6 drop-down
menu to Clock Output (see Figure 34).
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033
Figure 34. MP6, Clock Output
To set the value of BCLK, go to the PLL & Clock Control tab
and change the value of the Output Clock Frequency drop-
down menu to the desired division on MCLK (see Figure 35).
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034
To:
Self-boot
XTAL
To: Main
Blocks
CLOCKOUT
Figure 35. Clock Output Enabled/Divided
Now, set the input of the ADAU1772 to be the digital microphones
instead of the ADCs by toggling the appropriate Decimator Source
settings. Navigate to the PGA/ADC tab to find and set the
following switches (see Figure 36).
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035
Figure 36. Decimator Source
The digital microphones can now be routed via the appropriate
inputs on the
Audio Input cell.
Headphone Output
The headphone output, J23, connects to any standard 1/8-inch
mini-plug stereo headphones. By setting the HP_EN_L and
HP_EN_R bits in the headphone line output select register
(Address 0x0043), the output pins can be driven either by a
line output driver or by a headphone driver. Headphones can
be driven either single ended or differentially, and there are
bits to disable the LN and RN pins if single ended.
Line Outputs
The analog output pins, J19 and J21, can be used to drive
differential loads. In their default settings, these pins can
drive line loads of 10 Ω or greater.
To use an external speaker, wires can be soldered to the
unpopulated header pads, J13 and J16 (see Figure 37).
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036
Figure 37. Unpopulated J13 and J16 Headers