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Thread: T4.0 Re-assigning pins to get more analogue inputs

  1. #1
    Member houtson's Avatar
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    T4.0 Re-assigning pins to get more analogue inputs

    Don't know if this is easy, hard or impossible....

    Audio Project using T4.0 and Audioboard Rev D.

    Rev D knocks out a number of analogue inputs and I've got 6 pots that I want to read - not enough usable topside analogue pins and trying to avoid bottom pins.

    Is there anyway to re-assign a couple of digital pins to analogue (e.g. pins 2&3 to A10&A12)?

    Any ideas appreciated, cheers, Paul

  2. #2
    Senior Member+ defragster's Avatar
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    If not using SPI for RAM/DISPLAY/SD then pin #13 is free, And #15 is only used when Audio pot board is in use.

    With those two and #'s : 14, 16, 17, 22 that is 6 analog pins?

    Other than using those pins - it doesn't seem as though analog could map from digital pins or it would be noted.

    IIRC the i2c pins to Audio #'s: 18/19 , Are only used at startup to prep the Audio chip, and not required after that? Though having pots connected during that would likely be a stopper unless they were switched out - and then i2c pullups would affect the analog pots.

  3. #3
    Member houtson's Avatar
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    Thanks for looking at this...

    I'm using 14,15,16 &17 at present - so got 4 good.

    Trying to use 22(A8) but lots of noise no matter what I do (closeness to MCLK?) - may be able to do more shielding / filtering but it's jumping all over the place and still short of 1 .

    Using I2C (18 &19) for a NeoTrellis button pad as well as the AudioBoard so 18/19 are out

    Not using SPI but didn't think 13 was analog?

  4. #4
    Senior Member+ MichaelMeissner's Avatar
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    Quote Originally Posted by houtson View Post
    Not using SPI but didn't think 13 was analog?
    Yes, pin 13 is not an analog pin.

  5. #5
    Senior Member+ defragster's Avatar
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    Quote Originally Posted by MichaelMeissner View Post
    Yes, pin 13 is not an analog pin.
    opps - quite right ...

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