EVAL-AD7472CB Datasheet, PDF (8/14 Pages) Analog Devices – Evaluation Board for 12-bit high speed, low power, successive-approximation ADC

EVAL-AD7472CB
Use the mouse or the keyboard to highlight the configuration
file and load it by clicking the "load" button.
The "Analog in" section shows the analog input range and
DC offset voltage.
The user can then select the required number of samples and
sampling frequency. Note: While the AD7472 data sheet
specifies a maximum clock frequency of 26 MHz, the on-
board crystal oscillator outputs a 25MHz clock. Therefore
the max. sampling frequency will be less than that specified
on the data sheet. An external clock frequency (up to the max
specified on the data sheet) can be applied via the external
socket, SK1.
Click the OK button to return to the main screen.
MAIN SCREEN
The top left part of the main screen contains eight buttons
which are selected using the mouse or by using the function
keys from the keyboard. These buttons and the actions they
perform are:
F1: Info. This button shows information on the software.
F2: Setup. This button activates the setup menu.
F3: Samp. When this key is pressed, the software causes
the AD7472 to perform a number of conversions as
determined by the setup menu (see above). The data
from these conversions is then analyzed by the AD7472
evaluation software. Another set of samples may be
taken by pressing the F3 key again.
F4: Cont. Pressing this button causes the software to
repeatedly perform conversions and analyze them.
Once the conversions and analysis has been done for
one set of samples, the software automatically repeats
the process. It continues to do this until the ESC key
is pressed.
Figure 5. Setup Menu Screen
F5: Save. This saves a set of samples to a file for use either
at a later date or with other software. The samples can
be saved either as "volts", "ints" or "binary". The
format of all these files is ASCII text. Note that the
AD7472 software can only load files saved in the "ints"
format. Files saved in the "volts" and "ints" formats
can be used with packages such as Mathcad. Files
saved in the "binary" format are for viewing purposes
only.
F6: Load. This allows the user to load data from a file
with a .DAT extension. Only data that was saved as
ints can be loaded and analyzed. A configuration file
must be loaded via the "F2 Setup" menu before the
data file can be analyzed. If there is no EVAL-
CONTROL BOARD connected to the PC, then the
"no prog" button in the "F2 Setup" menu must be on.
Once a configuration file has been loaded, the data
loaded from the .DAT file is analyzed according to
the settings in the "F2 Setup" menu.
F7: Reset. Choosing this option resets the EVAL-CON-
TROL BOARD.
F10: Quit. This quits the AD7472 evaluation software and
returns control to the operating system.
INFORMATION WINDOWS
There are three information windows at the top of the main
screen. The left-hand window is the configuration window
and gives details about part being evaluated. It shows the
name of the program that has been downloaded to the EVAL-
CONTROL BOARD, the sampling frequency, the number
of bits, the analog input range of the part and the output code
format of the part. The right-hand large window is the Status
window. This window provides feedback to the user as to
what operations are currently being performed by the soft-
ware and also displays error messages.
Test Mode
At the top right of the main screen are the Test Mode buttons.
These buttons determine what sort of testing is done on the
samples captured by the software. Both an ac analysis and dc
analysis can be performed. The function of these buttons are:
fft plot
Choosing this button causes the Digital Spec-
trum Analyzer to appear at the bottom of the
screen.
Histogram: Choosing this button causes the Histogram
Analyzer to be displayed at the bottom of the
screen.
There is one other button near the top of the screen, beside
the "F10 Quit" button. This is:
blackman-harris:
When performing a Fourier transform
of the sampled data, this button determines whether
or not the data is windowed by a blackman-harris
window before the transform. When this button is
on, the data is windowed. When this button is off,
the data isn't windowed. See the Digital Spectrum
Analyzer section for more details.
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