EVAL-AD7912_15 Datasheet, PDF (8/16 Pages) Analog Devices – Evaluation Board for 1 MSPS, 2-Channel, 12-/10-Bit ADCs

EVAL-AD7912/AD7922
the graph will keep the same axis settings as for the previous set
of data samples. There are additional checkboxes in this section to
allow the user to control the vertical and horizontal grids and
data points.
The lowest section of the box will show either a fast Fourier
transform (FFT) of the data or a histogram showing the number
of occurrences of each particular code read back. The FFT (the
default option) is typically used when the user is concerned
with examining an ADC’s performance in the frequency
domain, whereas the histogram gives an indication of the
ADC’s performance in terms of dc signals. The option displayed
can be changed by clicking FFT Mode/Histogram Mode in the
upper right of the box.
Setup Menu
The Setup Menu dialog box allows the user to load the required
configuration file, the ad7912.cfg or the ad7922.cfg, for the
evaluation board. The configuration file provides the software
with detailed information about the AD7912/AD7922 evaluation
board and the part connected to the EVAL-CONTROL-BRD2.
For example, it provides information about the number of bits,
maximum sampling rate, output coding, maximum analog input,
power supply requirements, and so on. The configuration file
also tells the software the name of the DSP program file to
download to the EVAL-CONTROL-BRD2. These files are
supplied by Analog Devices with the evaluation board.
The Setup Menu dialog box allows the user to select the
number of samples required, the sampling frequency, and the
channel to be converted on (Channel 0 for VIN0 and Channel 1
for VIN1). Figure 5 shows the Setup Menu dialog box.
SETTING UP EVAL-CONTROL-BRD2
The following text describes how the evaluation board, EVAL-
CONTROL-BRD2, and software should be set up for the user to
begin using the complete system. The EVAL-CONTROL-BRD2
and evaluation board should be connected together (via the 96-way
connector). The power should be applied to the EVAL-CONTROL-
BRD2. At this stage, the red LED should be flashing, which indicates
that the EVAL-CONTROL-BRD2 is functional and ready to receive
instructions. The software should be loaded before the printer
port cable is connected between the EVAL-CONTROL-BRD2
and the PC. This ensures that the printer port has been initialized
properly. The printer port cable can then be connected between
the PC and EVAL-CONTROL-BRD2.
Running the Software
With the hardware set up, the user can use the software to control
the EVAL-CONTROL-BRD2 and the evaluation board.
In the software the user should select the File menu and click
Setup. This displays the setup form. A window on the left of the
setup form lists all the available configuration files. The config-
uration files are text-based files containing information about
the particular evaluation board to be tested. The information
includes the part name, number of samples to be taken, default and
maximum sampling frequency, power supply settings, and so on.
The configuration file also contains the name of the DSP program
file, which is to be downloaded to the EVAL-CONTROL-BRD2.
The user should select the relevant configuration file and click
Load. The EVAL-CONTROL-BRD2 will be reset and the DSP
program will be downloaded. When the download has been
completed, the power supply settings indicated in the config-
uration file are set and the user may hear some of the relays
clicking. The pull-down menu items such as Select No. Of
Samples and Select Sample Frequency will have been set to the
default values specified by the configuration file. The user is free to
change these at will and should select the channel to be converted
on as well. Once all the settings have been decided, the user can
click Close to return to the main setup form.
Figure 5. Setup Menu Dialog Box
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