6 Replies Latest reply on Oct 22, 2020 9:44 PM by AH_96

    Capsense Issue

    gibe_285051

      Hello Cypres community,

       

      I have an issue with the Psoc 4 - CY8C4045AZI-S413

      I'm developing a Passenger Control Unit for seats, for environmental qualification tests, when I put the PCU in a climatic chamber and start from -40 Celsius degree to 25 Celcius degree, the Capsense module no longer works anymore.

       

      I can't enable the sensor auto reset because the user can hold the button more than 30 secs.

       

      Software specifications :

      screenshot_capsense.JPGscreenshot_capsense_1.JPG

       

      Thank in advance for your help !

        • 1. Re: Capsense Issue
          AH_96

          Hi gibe_285051

           

          Please let us know the exact behavior that you are observing. Are the CapSense sensors false-triggering? Or are the not sensitive anymore?

          What is the behavior once the sensors are taken out of the climatic chamber - Do they return to normal operation?

          How rapid is the temperature change from -40 to 25 degree Celsius? Note that CapSense is sensitive to temperature changes and the raw counts will be affected by the temperature. If the temperature change is gradual, the baseline tracking algorithm will make sure that the baseline is continuously updated.

           

          Best regards,

          Hari

          • 2. Re: Capsense Issue
            gibe_285051

            Hi AH_96,

             

            Thank for your help,

             

            Are the CapSense sensors false-triggering? Or are the not sensitive anymore?

            All sensors are not sensitive anymore.

             

            What is the behavior once the sensors are taken out of the climatic chamber - Do they return to normal operation?

            If I restart the unit, the capacitive keys work again, otherwise it remains insensitive.

             

            How rapid is the temperature change from -40 to 25 degree Celsius?

            stabilization at -40C then 30 min to ramp up to 25C.

            • 3. Re: Capsense Issue
              AH_96

              Hi gibe_285051

               

              This issue is due to the temperature variation of CapSense. Is there any mechanism for temperature detection? if so, you can use this to restart CapSense by calling the CapSense_Stop and CapSense_Start APIs.

               

              If that is not possible, can you share the log of the raw count and baseline over the temperature range? This would help us identify any firmware fix for this.

               

              Best regards,

              Hari

              • 4. Re: Capsense Issue
                gibe_285051

                I don't have any mechanism for temperature detection so I'll try to log the raw count and baseline , I come back to you with the log

                Thank for your help.

                • 6. Re: Capsense Issue
                  AH_96

                  Hi gibe_285051

                   

                  I see the raw counts and baseline reaching a low value - 0 at T = 15.40.

                   

                  Is there any external reset event that is causing this? Because I see that the raw counts are getting recalibrated after this point.

                  You can see this in the data shared for BED_Sns0. The

                   

                  You must not use smartSense for applications such as these. You can see that the resolution is changed from 12 bits to 11 after this "reset" event. You can see the parameters set by smartSense and then set these in manual tuning.

                   

                  Best regards,

                  Hari