http://www.national.com
7
Figure 6: System Settings window
4.4 Power Supply Connections
In both the computer and manual modes, the
analog supply voltage (V
A
) can range between
+4.5V and +5.5V. Typical supply currents when
applying an external supply to TP12, 5P0V_REM
are as follows:
•
for +4.5V
- I = 9mA
•
for +5.5V
- I = 11mA
Note: A majority of this current is for powering
devices external to the ADC122S655. When
operating in the computer mode, the supply
voltage for V
A
can be applied externally or
supplied directly by the WV4 board through J6.
The external supply voltage is selected by placing
a shorting jumper across pins 1 & 2 of JP11 and
applying a +5.0V power source with a 300mA
current limit to TP12 and grounding TP13. To use
the supply directly from the WV4 board, place a
shorting jumper across pins 2 & 3 of JP11. For
the best performance, use an external supply.
The +3.3V required to power the EEPROM is
obtained through J6 from the WV4 board. LED
D4 on the evaluation board will be lit red indicating
the EEPROM is powered.
When operating in manual mode, always use an
external supply. Apply a +5.0V power source with
a current limit of 300mA to TP12 and ground
TP13. Place a shorting jumper across pins 1 & 2
of JP11.
5.0 Software Operation and Settings
The WaveVision 4 software is included with the
WV4 board and the latest version can be
downloaded for free from National's web site at
http://www.national.com/adc
. WaveVision
software version 4.4 or later is required to
evaluate this device with the WaveVision system.
To install this software, follow the procedure in the
WV4 Board User's Guide. Once the software is
installed, run and set it up as follows:
1. Connect the WV4 board to the host computer
with a USB cable.
2. From the WaveVision main menu, go to
Settings and then Board Settings to open the
System Settings window (
Figure 6
) and select
the following:
•
WaveVision
4.0
(USB)
•
Number of Samples: 2K to 32K, as
desired
•
Data Format: Two’s Complement
3. Apply power as specified in Section 4.4, click
on the
"Test"
button and await the firmware
to download.
4. Click on the
"Accept"
button to close the
System Settings window.
5. Select the channel to collect data from, either
channel A, B, or A & B (
Figure 7
).
6. After the steps outlined in Section 3.2 are
completed, click on ‘Acquire’ then ‘Samples’
from the Main Menu (you can also press the
F1
shortcut key). If a dialog box opens, select
‘Discard’ or press the
Escape (Esc)
key to
start collecting new samples.
WaveVision main menu will display an output plot.
Make sure there is no clipping of data samples.
Click on the software histogram tab and ensure
data does not exceed the limit of the device. The
samples may be further analyzed by clicking on
the magnifying glass icon, then clicking and
dragging across a specific area of the plot for
better data inspection (
Figure 8
). See the
WaveVision 4 Board User's Guide for more
details.
