• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 29 subscribers
  • Views 357 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Starting ADC sampling with useful signal

SabryLu
Prodigy 120 points

Hello,

I am using the Tiva C LaunchPad  TM4C123G and CCS v6.1.0

I should sample an analogic periodic signal, I want  the ADC conversion to start when there is useful signal, for doing that, should I put a threshold value or there is another way? Thanks in advance!

  • 0
    Guru 47900 points

    My small tech firm "likes" your question.   Rarely has such appeared - here/other fora...  Shows a desire/consideration for excellence...

    That said - certain professional schools teach us to be (always) "on guard" when language such as, "Ever, never, easy, quick or useful" appear.   Who defines "useful" - might that definition be dependent upon other facts - thus far - unspecified?  

    Should your signal (really) be periodic - and contain well defined "peaks/troughs" - an analog comparator (set to trigger the MCU upon either) may prove worthwhile.   Yet - should the signal vary in level - how can you "dynamically alter" your input signal trip points - so that you may properly initiate conversion?   (our firm often follows your suggested method - but via an M4/7 MCU equipped with multiple DACs & internal analog comparators.   The DACs prove far superior to the broad/stepped, fixed, comparator voltage levels - found w/in some MCUs.)

    On occasion - when your input signal is bit unknown - it may prove productive to make multiple, high-speed, un-triggered (test) conversions first - and use that data to set appropriate trip-points - for your (subsequent) triggering analog comparator(s).