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TM4C123GH6PM: Is it possible/practical to use more that 2 ADC's?

Marshall Folkman
Intellectual 720 points
Part Number: TM4C123GH6PM
Other Parts Discussed in Thread: ADS7924

Hi,

I have been using the Tivaware firmware libraries on the TM4C123GH6PM for some time. I have a complex project that I always seem to be adding more bells and whistles to. On this project I am using both ADCs and I would like to add a 3rd. I know that the microcontroller only has two ADC modules, but it does have many pins available that can be configured for ADC use. Is it possible and/or practical to constantly (every 1 second or so) reconfigure one of the ADCs to switch back and forth between two pins? In other words, can I have two pins share the same ADC module by constantly re-configuring the ADC module back and forth? And if so, how do I implement it?

Any thoughts and/or suggestions would be appreciated! 

Thank you!

Marshall

  • 0
    Guru 117855 points

    My friend - love/salute your use of "possible/practical" - more here would benefit from such "amplified/emphasized"  reader direction.

    To your issue - Yes - indeed it can be done.    But - as w/so much in Engineering - Trade-Offs & Compromises ARE demanded.     And - as always - "Devil luxuriates (builds condos) in such detail."

    Aspects of your Conversion Speed - as you surely know - will undeniably suffer.    To what degree - difficult to tell.    (it is likely "too soon" for you to have gauged "Just" what you seek - or require)

    I suggest that you dedicate one of the two MCU's ADC to your, "Most critical functions" - its twin - may serve as, "Marshall's Experimental Forum."     Such "Self-Test" - User Directed Experiment - most always - proves best in such circumstances.

    Should performance suffer - prove unbearable - you may ADD a, "Purpose Built" external ADC - adding to your  "ADC inventory."      (on more than one board - firm/I have, "Done just that" - usually adding a higher Res ADC - not so much for "accuracy" - but for "Dynamic Signal Accommodation.")

    Sounds fun...

  • 0 in reply to cb1_mobile
    Guru 117855 points

    Mercî monsieur.     And - may it be noted - that such "good" home (for an added ADC) - is likely,  "your" home.

    To that end - as, "Minimization of (both) cost/size (usually) is sought" may I suggest vendor's, "ADS7924" - an I2C based, (pin-saving) 12 bit, 4 Channel ADC - small in size (3x3mm - do not sneeze!) & cost!

    Again - this IS a vendor part - thus our (normal) quota of, Eval Boards, T-shirts, & Mugs "expands" - may require  "747 heavy" to transport ((this month)...