Q:
How do I use an input clock to drive sampling in the ADIS16448, when I am using the EVAL-ADIS to evaluate it?
A:
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This requires the use of (1) ADIS16448/PCBZ, (1) EVAL-ADIS, a function generator, interface cable and a PC, which has the IMU Evaluation software (v1.8.0 or later) installed.
Use the following steps to configure the ADIS16448 and IMU Evaluation software to run off of an input clock source.
- Use the ADIS1644x Wiki Guide to install the ADIS16448/PCBZ on the EVAL-ADIS. and to install the IMU Evaluation software on a PC.
LINK: http://wiki.analog.com/resources/eval/user-guides/inertial-mems/imu/adis16448 - Hook the function generator output up to the DIO4 test point (EVAL-ADIS) and the ground pin on J3, as shown below.
- Set the function generator for a pulse waveform, using the following settings: frequency = 1000Hz, pulse width = 50us, magnitude = 3.3V and offset = 0V.
NOTE: The goal is to apply a positive, "0V to +3.3V pulse." Function generators often assume a 50-ohm load when reporting magnitude. For our setup, we actually set the magnitude for 1.65V, which produces 3.3V into a high-impedance load (DIO4). If you aren't sure about this, measure the signal before applying it to the input. +6.6V could damage the unit or evaluation system. - Hook the USB to the PC, launch the IMU Evaluation software package and verify basic function in the ADIS16448.
- Go into the Register Access menu and change the SMPL_PRD setting to 0.
- While making sure that the clock signal is disabled, go back to the Main Screen and test the response again. You should see that there is no sensor response, with the clock still off.
- Enable the clock and test it again.
As we can see from the response on the far right, the external clock has enabled sampling and a response in the Main Window.
Use the following steps to configure and use the Data Capture function with an external clock. Note that the images reflect the software design at v1.8.1, so more recent window designs may differ in appearance, but will support the functions that the following steps illustrate:
- Click on Data Capture at the top of the Main Window. When the Data Capture window appears, click on Advanced Options.
- The Advanced Options menu provides an opportunity to enable the use of the external trigger. Click on this box and then enter the external clock frequency. This entry enables the data capture time computation in the Data Capture menu.
- Click on OK to return to the Data Capture menu and enter the storage location and file name for the data file.
- If you use the Browse function, click on Save to set the location and file name.
- Select the registers for the data capture by checking on their boxes, set the Record Length (total number of data points) and then click on Start.
I hope that this helps. Keep your comments coming. We sincerely appreciate your interest in our high-performance MEMS IMUs and eagerly look forward to your feedback.
Very best regards,
NevadaMark