2 Replies Latest reply on Feb 24, 2013 4:53 AM by user_14586677

    how  make 90 seconds timer

    rajendra.p

      Hi ,

         

            how to make a 90 seconds timer ,i.e after 90 seconds it must enable a ADC, here ADC is started by Hardware triggered by the 90 seconds timer .

         

      Thanks

        • 1. Re: how  make 90 seconds timer
          user_1377889

          The usual way to accomplish a long-time timer is

             

          Setup an interrupt-generating short-time timer (like 10 to 100ms)

             

          At each interrupt increase a counter (can be a 32-bit global var)

             

          in main()-loop check counter for exceeding a given value

             

           

             

          or

             

          At start of time set counter to a pre-defined value

             

          At each interrupt decrease the counter (can be a 32-bit global var)

             

          in main()-loop check counter for expiring.

             

           

             

          Happy times

             

          Bob

          • 2. Re: how  make 90 seconds timer
            user_14586677

            You could also use RTC derived one pulse per second interrupt, from

               

            the TRM -

               

             

               

            Real Time Clock

               


            One of the major uses of the kHzECO oscillator is for RTC
            implementation. The block level illustration of the RTC
            implementation is shown in Figure 14-7.
            The RTC timing is derived from the 32 kHz external crystal
            oscillator, as shown in Figure 14-7. Therefore, for the functioning
            of the RTC, the 32 kHz external crystal must be
            enabled through the register SLOWCLK_X32_CR [0]. The
            generated 32 kHz is divided to achieve a one pulse per second.

               


            The register PM_TW_CFG2[4] enables one pulse per
            second functionality.

               


            By enabling the bit PM_TW_CFG2[5], the RTC generates
            an interrupt every second. The interrupt is routed through
            the DSI and is brought out as an interrupt. See the UDB
            Array and Digital System Interconnect chapter on page 221
            for more details on usage. RTC functionality is available for
            use in all power modes except the Hibernate mode.

               

            Looks like you can use this HW feature w/o having to place

               

            RTC module. See PM_TW_CFG2 register information in

               

            PSOC 3 register TRM.

               

             

               

            Regards, Dana.

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