7 Replies Latest reply on May 7, 2017 1:54 PM by user_78878863

    Synchronising two PSoC boards

    antonio.stanesic

      Hello,
      I am currently working on a project in which there is a need to synchronize the clocks between the two physically separated PSoC 5LP boards. Desired frequency (that needs to be the same on both boards) is in range from 100kHz to about 150kHz, and the error should be as low as possible. Since the IMO tolerance is at best +-1%, on a clock of (for example) 120kHz it produces an uncertainty of +-1200Hz, which is a total of 2400Hz. Such error is not satisfying enough.

         

      I am thinking of using an external 32kHz oscillator to trim the IMOs of both boards. Using 100ppm crystals, it should produce an error of about +-0.05%, which is considerably better. If I understand trimming correctly, there is not a great benefit of using a more precise crystal, since internal trim register limits the achievable accuracy to +-0.03%. Is it possible to get better results than that using another method?

         

      How does the IMO trim API work - is it possible to "calibrate" the IMO using the 32kHz ECO at startup, or does the trimming need to continue during the time of operation?