AnsweredAssumed Answered

External clock with EVAL-ADIS and ADIS16485

Question asked by Scogg45 on Feb 27, 2013
Latest reply on Feb 28, 2013 by NevadaMark

I would like to use an external trigger with the EVAL-ADIS, the ADIS16485, and IMU Eval Software.

 

My Setup:

I am using the EVAL-ADIS board and the ADIS16485 IMU.

It is hooked up via USB and the jumper on JP1 is 3.3v (two top left pins jumped)

I am using a ribbon cable plugged into J1.

External clock hooked up to DIO4 and GND.

Clock rate is 100 Hz.  (Source: Tektronix AFG310)

Clock voltage = 1.65v – This gives me a 3.3v pk to pk.

Offset voltage = 0.84v – This keeps the voltage from going below 0v on the O-Scope

Clock is being monitored on an oscilloscope.

External Trigger is checked in the Data Log Advanced Options.

100 Hz, our clock rate is typed into the box asking for rate.

A message stating “ext. trigger” then appears by the test start button.

Data Ready Synchronization Enabled is “NOT checked” (If I leave it checked it goes into super freak-out mode and looks for a diver. I have unplug the USB cable and plug back in)

 

Observation:

When I use the external trigger, my sample time is too short. For example if I set my record length to 1000 and my rate is 100 Hz – The capture time correctly displays 10 seconds. When I click start it samples for a lot less than 10 seconds. The test ends early. Sometimes it may go for about 2 seconds and other times 5 seconds. I am monitoring the clock on an O-scope and am not fluctuating more than 1Hz.

 

What I want:

The IMU to sample based on the clock input.

 

The Why:

I will eventually use the external clock to become a common sample clock for different data acquisition devices.

 

Background:

It has been a long time since I have messed around with digital devices. I am sure there may be a lot better ways of doing this than what I am doing. We just purchased labview. I will be slowly getting to a purely SPI communication process. I am not there yet. Please keep that in mind when replying to the post. For now I would really like to use the EVAL-ADIS board.

 

Questions:

Do my procedures/settings appear correct?

Is the software evolved enough to do this? Is this possible yet with the eval software?

 

Thank You,

Jared Scoggins

Outcomes