0 Replies Latest reply on Mar 16, 2011 4:21 AM by pavankumar.vibhute

    CapSense debounce setting and the response time

    pavankumar.vibhute

       In Capsense_CSD, if the debounce is set to say 5 then it means the finger has to be present on the button for so many number of scans. In this case, for five scans the finger has to be on the button. The debounce feature removes the high amplitude high frequency noise.

         

      But when the CapSense is used in the applications, where the main loop is long, the response time of Capsense button may be very poor if the debounce is set to high number. CapSense buttons will be scanned in continuous loop. If the loop is long and the debounce is high like 5, then this long loop should be executed 5 times for the button to be detected as ON. This gives very slow response. 

         

       

         

      Solutions to avoid this:

         

      1) Debounce value: Do not set this as high number or dont leave it as default value which is 5. If the loop is long then already the interval between scan is long so high debounce number is not needed. Use the debounce value of 2.

         

      2) Do multiple scans in the same loop: Inside the long loop, scan the CapSense buttons twice or more. Decide your debounce time that is how time you want your button to be active to be detected as ON. This depends on the noise freqency in the system. Then do the multiple scannings so that scannings are done to cover the required debounce time.