3 Replies Latest reply on Aug 23, 2018 7:56 PM by rzzh

    Capsense buttons won't work under high temperature and high humidity

    wangyong_1658156

      CY8C4025AZI-S413 is used for the project. I configured 12 capsense buttons with smart-sensening mode. C-sheild and C-tank was left floating. It worked normally during normal environment but could not be waked up after 24hrs testing with 70 and 90% RH.

        • 1. Re: Capsense buttons won't work under high temperature and high humidity
          rzzh

          Dear Yong,

           

          A possible case is: the temperature and humidity changes slowly, baseline will follow rawcount timely, but with temperature and humidity increasing, rawcount level may go to the top of the range scale of resolution and becomes saturated. 

          Another case is, when the DUT put in the environment with 70℃ and 90% RH from common environment, the cp of system will increase quickly, CapSense with SmartSense may not follow the change smoothly, may lead to rawcount saturation or baseline not able to follow rawcount timely.

          For the first case, suggest to change target auto-calibration level from 85% to less than 65% and use Auto sense clock, and enable baseline auto-reset.

          For the second case, beside above suggestions, recommend to change to manual tuning mode, tune and get a set of good parameters. Monitor rawcounts and baselines in run time, If environment causes rawcounts or baselines changing worse than a normal scale, re-calibrate CapSense parameters in firmware. 

           

          Thanks,

          Ryan

          • 2. Re: Capsense buttons won't work under high temperature and high humidity
            wangyong_1658156

            Thanks Ryan,

             

            Will baselines change after being set to manual tuning mode? We used manual tuning mode for a product but we got bad luck that quite a lot of our products in filed could not be waked up sporadically in field. which parameters we should monitor, If we still want to use manual tuning,  I want to build up a spread sheet and collect quite a few products in different environment to make sure the parameters are correctly adjusted.

            • 3. Re: Capsense buttons won't work under high temperature and high humidity
              rzzh

              Hi Yong,

               

              There are many factors on baseline changing. Basically, if you use same Modulator clock, Sense clock, Sense clock mode, Resolution and IDAC settings with SmarSense, baselines will not change.

              Yes. Manual tuning will ask for good production consistence. In other words, with good manual tuning, you can also pick up NG products effectively.

              In my mind, some parameters are important to guarantee the consistence of products when using manual tuning (it should work for SmartSense too):

              1. IDACs,

              2. Raw counts level with no touch,

              3. Baselines initialized after power on,

              4. Sensor signals with fixed touch size and materials,

              5. Raw counts/Baselines differences among all sensors.

              6. SNR.

               

              Thanks,

              Ryan