3 Replies Latest reply on Jan 7, 2015 6:28 PM by MichaelF_56

    Sleep Mode on 20736S

    phgic_2174146

      Does not having P0 pulled high have any impact on the ability of the module to enter sleep mode?  I have been told that it impacts deep sleep mode, but I can't determine if it that is the only impact.  I have seen some mention of this on this site: Re: Questions sleep and deep sleep modes on BCM20737 but only in reference to deep sleep mode.

       

      The reason I'm asking is that I'm not seeing the device enter sleep mode when looking at the current draw.  I don't seem to get below 100 micro amps.  The device is normally always connected or advertising so I need to make sure I can sleep whenever possible to conserve battery life.  I'm trying to rule P0 out as a potential issue.

       

      Also, is there any correlation to the fine timer interval and battery life (e.g. shorter intervals leading to more power consumption)?

       

      Thanks!

        • 1. Re: Sleep Mode on 20736S
          MichaelF_56

          My understanding is that it could affect either.


          GPIO:P0 should be pulled high (via 10k), or the key-scan feature of the device may think a key on a keyboard is pressed and it will stay awake to perform further scanning.

           

          Based on my understanding of this thread, it appears that the fine timer could indeed affect power consumption: FineTimer

          • 2. Re: Sleep Mode on 20736S
            phgic_2174146

            Thanks!  I'll try to work up a new prototype that I can test this with.

             

            For the attached thread, I'm don't see a correlation with power.  Most of this discussion seems to revolve around attempting to have very small cycles.  What I'm trying to determine is if increasing the fine timer interval from 250ms to 500ms would have a meaningful impact on power consumption - assuming I can get into sleep mode.

            • 3. Re: Sleep Mode on 20736S
              MichaelF_56

              I checked with the developers today and most definitely, on the BCM20736/37, there is an impact on power consumption that is proportional to the fine timer setting.

               

              Essentially, if the fine timer fires more often (i.e. wakes up, handles an event, then goes back to sleep), the part will consume more power.

               

              On the BCM20732 (different firmware), this was not as much the case because the firmware/fine timer function was architected differently.

               

              VikramR_26 jota_1939431