GPS Pulse Per Second



  • HI,
    I am wondering if it is possible to access the Pulse per second (PPS) from the GPS device on an IO pin? n This is needed for some critical RT tasks where I need phase stability for many many hours.

    Is it possible to use the GPS with the RTC? Whats the accuracy/stability of the RTC? Is it temperature compensated?

    NTP time is not accurate enough for my application.

    Many thanks
    Neil


  • DeveloperWorld

    Hi @NeilC

    Checking out the CXD5602GG_technical_manual shows that there are a few options for SPR_GNSS_1PPS_OUT signal.

    Looking at the schematic of the main board you can track the GNSS_1PPS_OUT signal from the CXD5602 chip on the main board out via the B2B connector to the extension board where it then ends up on something that looks like a test point called CL1. The CXD5602PWBEXT1_part_layout of the extension board will help you locating this point.

    Looking into CXD5247GF_technical_manual_02.pdf page 6 will give you and overview of the oscillator/xtal used as RTC source.

    CXD5602GG_technical_manual.pdf page 20 shows a table of Frequency tolerance for RTC clock in.

    The CXD5602_user_manual page 170 explains abit on the clock sources used for RTC.

    Hope these pointers will help you on your way. If not please let me know.

    BR
    Karl