Author Topic: How to sample 8 pins at 24 MHz and detect for 50ms periods...  (Read 1309 times)

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Offline alank2Topic starter

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How to sample 8 pins at 25 MHz and detect for 50ms periods:

all low
all high
mixed high and low

I want to make a logic probe type of thing that indicates the state of 8 lines.  The 50ms limits the LED changes to 10 Hz which is easily visible.  This way a quick pulse that you would never see in the LED would be visible.

What components would you recommend that can detect as small as a 40ns change (25 MHz)?  I don't need to know how many - just sample for 50 milliseconds and each line needs LOW, HIGH, or MIXED.
 

Offline alank2Topic starter

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Re: How to sample 8 pins at 24 MHz and detect for 50ms periods...
« Reply #1 on: April 15, 2016, 12:19:31 pm »
Thanks evg149 - I actually found a way to do it very efficiently with an xmega.  The gpio's on it have pin sensing so you can sense both edges on them using INTFLAGS after setting INTMASK for them.  I am doing the entire port.  Once I enabled the internal 32MHz clock, I can sense an edge at 35ns consistently!!
 


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