Analog Devices EVAL-ADAU1466Z, Руководство пользователя

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UG-1135 EVAL-ADAU1466Z User Guide
Rev. 0 | Page 16 of 45
5. Add two DSP Readback blocks to the project and set their
numeric format as follows:
a.
From the Basic DSP > DSP Function folder, click DSP
Readback (see Figure 54) and drag it into the project
space to the right of the toolbox.
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Figure 54. DSP Readback Block Selection
b. Repeat the previous step to add another DSP
Readback block.
c. The DSP Readback block uses the USBi interface to
read the value of a signal from the memory of the DSP
core as the algorithm is executing. The block passes the
signal through from its input to its output unchanged.
i.
Press the Read button to fetch the instantaneous
value of the signal passing through the block. It is
also possible to set the block to poll the value
repeatedly. This feature is useful for debugging,
but it increases the amount of processing, USB
communication, and screen refreshes performed
by
SigmaStudio substantially. Avoid setting a
large number of DSP Readback blocks to read
continuously because this action can cause the
PC to run slowly. Note that this action does not
affect the real-time processing on the
SigmaDSP
core.
ii. On each of the two DSP Readback blocks, click
on the blue dot to the left of the Read button to
read both blocks continuously (see Figure 55).
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Figure 55. Activating Continuous Read Back
iii. For one of the DSP readback blocks, change the
numeric format used to decode and display of the
value of the signal to 32.0 by typing 32 in the left
format box then pressing the
TAB key. SigmaDSP
uses a numeric format of 8.24 for audio signals.
6. Add an Single Slew Ext Volume block to the project space
as follows:
a.
From the Volume Controls > Adjustable Gain >
Clickless HW Slew folder, click Single Slew Ext Vol
(see Figure 56) and drag it into the project space to the
right of the toolbox.
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58
Figure 56. Single Slew Ext Vol Block Selection
b. By default, the Single Slew Ext Vol block has one audio
signal input. To add another channel, right click in the
empty white space of the
Single Slew Ext Vol block, and
select 1 > 1. Gain (HW slew) > Grow Algorithm from
the dropdown menu that appears (see Figure 57).
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Figure 57. Growing the Single Slew Ext Vol Block to Two Channels
7. Wire the blocks together as shown in Figure 58. Note that
the position of blocks in the diagram does not matter.
8. Click the Link/Compile/Download button (see Figure 28)
or press F7 to compile the signal flow and download it to the
hardware. The audio signal passes from the S/PDIF receiver
through the ASRCs into the DSP and the EQ filter, and
then out on the S/PDIF transmitter. To change the settings
of the EQ filter, click the blue icon at top of the block. Drag
the control slider in
SigmaStudio to change the filter gain
in real-time while the project is running.