4 Replies Latest reply on Jul 10, 2018 7:08 PM by msur

    PSoC63 Current Consumption RTC & RTC + 64 kB RAM Retention

    andre.vaas_2417461

      Hello,

       

      I have 2 questions:

       

      1. Could you tell me the current consumption of a PSoC63 in hibernate mode with running RTC? In the datasheet I only can find the value of 800 nA @ 3.3 V with the comment: "no clocks running". But the RTC counts as a "clock" I think? Could you tell me the value including RTC running with external 32 kHz crystal?

       

      2. Could you tell me the current consumption of the device, if everything is off except 64 k RAM retention and RTC running with external 32 KHz crystal?

       

      Thank you!

      Regards

      Andre

        • 1. Re: PSoC63 Current Consumption RTC & RTC + 64 kB RAM Retention
          msur

          Hello Andre,

           

          To your questions -

          1. The RTC (WCO primarily) consumes around 380 nA typical and 1 uA max (SID318) - this adds to the Max hibernate current of 800 nA at 3.3 V

          2. If you need SRAM retention, then you cannot go below deep sleep power mode. Hence the power consumption would be 7 uA typical (with internal buck enabled) - SIDDS1. With the WCO typical of 0.38 uA, this will be 7.38 uA.

           

          Let me know if you have any more questions.

           

          Regards,

          Meenakshi Sundaram R

          1 of 1 people found this helpful
          • 2. Re: PSoC63 Current Consumption RTC & RTC + 64 kB RAM Retention
            andre.vaas_2417461

            Thanks for your quick answers! With RAM retention, the current consumption is very high for a coin cell operated application.

             

            So as we are evaluating the chips from different manufacturers at the moment, I have to find a solution for periodically low power code execution. Programatically it will be a state machine. The state shall be available when the device is resuming. Is there some way, to realize that with the hibernate mode? Are there some dedicated RAM cells which can be used for that?

             

            If there is some way to control the state machine via the RTC time, then lets asume the state machine shall be processed every second (processing time is very short). Is it energetically meaningful, to set the system in hibernate or shall the deep sleep be used in that case?

             

            The Advertising will also be processed every 3 seconds. When an Advertising event occurs, does the CPU or System have to wake up from hibernation or does the radio work independently and let the CPU in hibernation?

             

            Thank you!

            • 3. Re: PSoC63 Current Consumption RTC & RTC + 64 kB RAM Retention
              andre.vaas_2417461

              And another question is: If the periodic Advertising intervall happens, can the CPU or main application get notified from this event? So the application processing can be aligned or post processed after the Advertising Event. It would be important that Advertising and processing is done one after another (battery peak drain in cold conditions + Vbatt drops has affect on external analog measurement circuitry).

               

              Thank you!

              • 4. Re: PSoC63 Current Consumption RTC & RTC + 64 kB RAM Retention
                msur

                Andre,

                 

                To your questions -

                1. If what you want to retain is less than 64 ( = 16 32-bit registers) bytes, then you can use the backup registers, which are retained across all power modes except off. The backup registers are accessible through BACKUP->BREG[i] (i = 0 to 15). You can store the state in these registers, put the device to hibernate and then wakeup using RTC alarm or switch press. If the interval between Hibernate is one second or more, then it makes sense to use Hibernate over deep sleep for power saving. As there is a good 500 us Hibernate to active transition and then the user code initialization also need to happen as configuration registers will not retained in Hibernate mode.

                 

                2. Regarding advertisement - Yes CPU needs to be active while doing Advertisement (as CPU manages the controller during advertisement + the system need to be active for providing the high-speed clocks required for BLE operation). However, in between advertisement, you can put the device to deep sleep. The BLESS controller takes care of waking up the CPU from deep sleep, send advertising packets again and then deep sleep (if you are calling Cy_SysPm_DeepSleep in while(1)). If you use Hibernate between advertisements (BLESS controller will not wakeup, you need to configure RTC or pin wakeup), then you will need to start the BLE stack again as the configuration will lost when the device enters Hibernate.

                 

                3. If you are looking for an event from the stack indicating advertisement is complete, then such an event is currently not available and will be available in the next PDL release (3.0.4 or 3.1.0).

                 

                Let me know if this answers your questions.

                 

                Regards,

                Meenakshi Sundaram R

                1 of 1 people found this helpful