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Synchronous Sensing


#1

Hi

If I have two or more FEZs, each FEZ connects with accelerometer.
I want these FEZs synchronize sensing. How could I do this?
And the Timer seems not accurate for sensing. For example, if my sampling rate is 200HZ (sampling one data per 5ms), If I set the timer to 5ms to get the data. The time span seems not exact the 5ms. Synchronizing and accurate sampling is very important for my project.
Thank you very much

Lin


#2

You may have to use register access so you can control the built in timers in the NXP processor.


#3

Would using a pwm pin into an interrupt port to get the timing and then read sensors in the interrupt handler work?


#4

Dear Mike and Gus:
Have any reference for your suggestions?
Tank you very much.
Lin


#5

Look in the be beginner ebook…

There is a section on pwm. Tells you how to generate a signal.

Wire the pwm port to an interrupt enabled port. See the brochure for the device for pin info.

Look at ebook for interrupt port usage.

Once you read the ebook you will see how easy it is


#6

You don’t say how you are pulling data from the accelerometer. Is it an analog output, SPI, etc? If each sample is timestamped does it matter that they are not synchronized?


#7

Thanks all, I will do some experiments. I will post the results here.

Thanks