init analog input w/o pullup #348
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Board and firmware folder for this pull request: |
DocMoebiuz
requested changes
Jan 6, 2025
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Board and firmware folder for this pull request: |
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Board and firmware folder for this pull request: |
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With last commit a new device type is added to keep backwards compatibility |
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Description of changes
In the actual code a pin for reading analog values is initialized with pullups enabled. When connecting a potentiometer to the pin this internal resistor is always parallel to the "upper" part of the potentiometer. The internal pullup resistor is ~35kOhm.
This results in a non linear behaviour of the potentiometer. For a 10kOhm potentiometer the deviation is max. 4% at 70% position, this increases for higher values of the potentiometer.
Examples are:
50kOhm: 16% deviation at 70% position
100kOhm: 26% deviation at 70% position
500kOhm: 56% deviation at 80% position
The code change is not to use the internal pullup resistor. Also setting the
pinMode()is not required as this is done during theanalogRead()function.Fixes #347