EVAL-AD7475 Datasheet, PDF (6/13 Pages) Analog Devices – Evaluation Board for 1MSPS, 12-Bit ADC

EVAL-AD7475/AD7495CB
Figure 2. AD7475/AD7495 Main Screen - FFT Mode
SOFTWARE DESCRIPTION
Included in the EVAL-AD7475/AD7495CB evaluation board package is a CD ROM which contains software for controlling
and evaluating the performance of the AD7475/AD7495 when it is operated with the EVALUATION-BOARD CONTROL-
LER. When the CD is inserted into the PC an installation program will automatically begin. This program will install the
evaluation software onto the users machine and will also install the technical Note for the AD7475/AD7495 evaluation board
as well as the datasheet for the AD7475/AD7495. All literature on the CD is in Adobe's Portable Documation format (PDF)
and will require Acrobat Reader^TM to be viewed or printed. The user interface on the PC is a dedicated program written
especially for the AD7475/AD7495.
The software which controls the Evaluation Board Controller and hence the AD7475/AD7495 evaluation board has three main
screens. The screen shown in Figure 2 shows the screen which appears when the software is run. The main function of the
screen is to allow the user to read a predetermined number of samples from the evaluation board and display them in both
the time and frequency domain. The screen can be divided into 3 sections. The upper most section of the screen contains the
control buttons, the menu bar and the status windows.The controll buttons allow the user to enter the set-up menu, take
samples, and get information about the software. There are also power down/up options in the control buttons. These buttons
allow the user to place the part into power down, and power the part up again. There are two powerdown modes associated
with the AD7475/AD7495, partial powerdown and full powerdown. To enter partial power down the ' PowerDown ' button
should be pressed once. To enter Full power down the ' PowerDown ' button should be pressed twice( see modes of operating
section of the AD7475/AD7495 datasheet ).
The menu bar allows the user to select which printer port is to be used to control the Evaluation Board Controller, load and
save data etc. The status window indicates the set up of the AD7475/AD7495 evaluation board, the number of samples taken
and any information messages that are generated.
The middle section of the AD7475/AD7495 Main Screen is a Digital Storage Oscilloscope (DSO). When samples are
uploaded from the Evaluation Board Controller they are displayed here. The samples can be displayed as either interger values
or as voltages . Once the samples are displayed clicking any point on the graph will display the sample number and the value
of the point directly beneath the cursor. Along the axis of the graph are the " zoom handles ". These allow the user to zoom
in and out to get a closer look at a particular sample if required. When another set of samples are taken the graph will attempt
to display all values collected unless the Hold Zoom check box is ticked. If the Hold zoom box is ticked the graph will keep
the same axis settings as for the previous set of data samples. There are additional check boxes in this section to give the user
control over the vertical and horizontal grids and data points.
The lowest section of the screen will show either a Fast Fourier Transform (FFT) of the data, or a histogram, which shows
the number of occurances of each particular code read back. The FFT ( default option ) is typically used when the user is
concerned with examining the AD7475/AD7495's performance in the frequency domain, while the Histogram will give an
indication of the AD7475/AD7495's performance to dc signals. The option displayed can be changed by clicking on the FFT
Mode/Histogram Mode button in the top right of the screen. Figure 3 shows how the Main Screen would look if the Histogram
Mode was selected.
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