Run the Demonstration (AD7768) - ArrowElectronics/data-storm-daq GitHub Wiki

Run the Demonstration

Signal source
Run the demonstration locally
Run the demonstration via ethernet

Signal Source

A signal generator with 2 outputs is used to generate the differential signals driving the AD7768 inputs. The AD7768 expects the input signals to swing between AVSS and AVDD1. However, the EVAL-AD7768FMCZ board is set up to use the ADA4896 buffers which offset the inputs by VCOM. VCOM starts out as an output (VCM_OUT) from the AD7768 at (AVDD1-AVSS)/2 and goes through select jumpers (0 ohm resistors) SL19 and SL15, and unity gain voltage follower as seen below. This means that the user is expected to provide a true differential input centered at AVSS, and the VCOM takes care of shifting it up.

By default, SL19 and SL15 are set to position A.

Set up the first channel to generate the desired signal
Set up the second channel for tracking the first channel
Set up the Second channel for signal inversion.

Run the demonstration locally

Power up the unit using this hardware configuration. Wait approximately 60 seconds for the unit to be fully functional.

IIO Oscilloscope will be automatically launched on the system desktop. No configuration is required.

Enable voltage4 ADC channel

Select a Plot Channel to be displayed in IIO Oscilloscope. Click on the check box in the Plot Channel window adjacent to voltage0

Capture Time Domain Signals

Press the Capture / Stop button to begin the capture process.

Capture Frequency Domain Signals with Frequency Markers enabled

Change the capture mode to Frequency Domain. Select an FFT Size and Average. Press the Capture / Stop button to begin the capture process.

Right click in the IIO Oscilloscope plot area. Select a marker option. Press the Capture / Stop button to begin the capture process with markers.

Note the information in the Marker window. This capture shows a signal source of 100 khz with harmonic components.

Shutting down the demo

Power down the target. Launch a Root Terminal. Type the following
```
  $ poweroff  
```
Wait 30 seconds and then you can safely power down the DataStorm DAQ

Run the demonstration via ethernet

Define the host PC IP address

A wired ethernet point to point connection between the host PC and the embedded target is required. Use this link for instructions on how to assign a static IP address to the host Ethernet adapter. Set the following values

IP address : 192.168.0.1
Subnet mask : 255.255.255.0
No entries required for the other fields

Connect to the target terminal

A wired Micro USB serial port connection between the host PC and the embedded target is required
Launch a linux terminal (like Tera Term VT or Putty) and connect using serial port
Select 115200 baud
Select the appropriate target COM port

Define the target IP address

Type the following at the terminal prompt to set the target IP address

$ ifconfig eth0 192.168.0.2 up

Launch IIO Oscilloscope

Note: IIO Oscilloscope creates a .osc_profile.ini file in the Users/UserName/Appdata/Local directory. The next time IIO Oscilloscope is opened, the existence of this file delays connection to the target. It is recommended to delete the .osc_profile.ini (if it exists) prior to launching IIO Oscilloscope.