ad8320arpz-reel Analog Devices, Inc., ad8320arpz-reel Datasheet - Page 15

• Manufacturer Part Number: ad8320arpz-reel
• Description: Serial Digital Controlled Variable Gain Line Driver
• Manufacturer: Analog Devices, Inc.

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The control software requires Windows 3.1 or later to operate.
To install the software, insert the disk labeled “Disk # 1 of 2” in
the PC and run the file called SETUP.EXE. Additional installa-
tion instructions will be given on-screen. Before beginning installa-
tion, it is important to close any other Windows applications
that are running.
When you launch the installed control software from Windows,
you will be asked to select the printer port you are using. Most
modern PCs have only one printer port, usually called LPT1.
However, some laptop computers use the PRN port.
Figure 56 shows the main screen of the control software. Using
the slider, you can set any gain in the AD8320’s 36 dB range.
The gain is displayed on-screen in dB and V/V. The 8-bit gain
setting byte is also displayed, in binary, hexadecimal and decimal.
Each time the slider is moved, the software automatically sends
and latches the required 8-bit data stream to the AD8320. You
Figure 52. Evaluation Board Silkscreen (Component Side)
–15–
can power down or reset the device simply by clicking the
appropriate buttons. The software also offers one volatile stor-
age location that can be used to store a particular gain. This
functions in the same way as the memory on a pocket calculator.
Overshoot on PC Printer Ports’ Data Lines
The data lines on some printer ports have excessive overshoot.
Overshoot on the pin used as the serial clock (Pin 6 on the D-
Sub-25 connector) can cause communication problems. This
overshoot can be eliminated by applying mild filtering to the
CLK line on the evaluation board. This can be done by putting
a small series resistor on the CLK line, combined with a
capacitor to ground. Pads are provided (C9, R4) on the com-
ponent side of the evaluation board to allow easy insertion of
these devices. Determining the size of these values will take
some experimentation. Depending upon the overshoot from the
printer port, this capacitor may need to be as large as 0.01 F,
while the resistor is typically in the 50
to 100
AD8320
range.