Analog Devices EVAL-ADAU1777Z User Manual page 13

UG-1055
Digital Microphones
Pulse density modulation (PDM) digital microphones can be
connected to standard 0.100" headers (J6 and J7). To use the
digital microphone headers on the EVAL-ADAU1777Z, ensure
that the proper settings have been chosen in SigmaStudio. Go to
the Pin/Pad Control tab (found in the Hardware Configuration/
ADAU1777 Register Control section). In the CLKOUT/
ADC_SDATA1/MP6 drop-down box, select Clock Output
(see Figure 34).
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 box to the desired division on MCLK (see Figure 35).
Figure 35. Clock Output Enabled/Divided
Set the input of the ADAU1777
instead of the ADCs by toggling the appropriate Decimator
Source settings. Go to the PGA/ADC tab to find and set the
following switches (see Figure 36).
The digital microphones can now be routed via the appropriate
inputs on the Audio Input cell.
To:
Self-boot
XTAL
CLOCKOUT
To: Main
Blocks
to be the digital microphones
Headphone Output
The headphone output, J23, connects to any standard 3.5 mm
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 bits are available
to disable the LN and RN pins if using single-ended.
Line Outputs
The J19 and J21 analog output pins can drive differential loads.
In their default settings, these pins can drive line loads of 10 kΩ
or greater.
To use an external speaker, solder wires to the unpopulated
header pads, J13 and J16 (see Figure 37).
Figure 37. Unpopulated J13 and J16 Headers
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EVAL-ADAU1777Z User Guide
Figure 36. Decimator Source