Step 1. Optimal CTMU current selection

mTouch

mTouch Cap Library Help
Step 1. Optimal CTMU current selection

 

To achieve the maximum of sensitivity the sensors must be charged to the voltage level about 75% of AVdd . The rounding error depends on the charge delay parameter.The rounding error in percentage is (100/CTMU charge delay) of AVdd. The recommended minimum value for the CTMU charge delay is 8 (default charge delay ) .This provides charge to the optimal level with rounding error about +-12.5% of AVdd. MTouchDebugCurrent(…) function returns the CTMU current source settings when the optimal charge delay value is 8. Assign this value to MTOUCH_CTMU_CURRENT parameter in mTouchConfig.h.

Microchip mTouchCap Software Library 1.41 - [July 18, 2012]
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