Configuring Unused Buttons - KBA82818

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Question: I have a PCB layout that is used for multiple projects, however, a few CapSense buttons are not used in every project. In these projects, the unused buttons are on the PCB but they are not defined on the overlay artwork. What is the right pin configuration for these buttons in PSoC Designer?

 

Answer:

The GPIO setting for the unused button inputs need to be configured as "Strong" and driven low. These pins should not be configured as buttons in the designer project. Often, the default designer setting is "Hi Z", but this may cause a problem if the unused buttons are capacitively coupled to adjacent buttons in the Hi Z state.