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RTOS/CC3220SF-LAUNCHXL: Clock timestamp precision

Michele Bruno
Prodigy 30 points
Part Number: CC3220SF-LAUNCHXL
Other Parts Discussed in Thread: SYSBIOS, CC3220SF

Tool/software: TI-RTOS

Hi All,

I'm using the system clock to syncronize my application to some UART packet data. I have also an external clock very accurate.

FIrst I've used the clock_settime() and  clock_gettime() but the precision is very bad.

Now I'm using  Clock_getTicks from xdc Module('ti.sysbios.knl.Clock')  and it is very good but with a millisecond precision. I tryed to change  Clock.tickPeriod from 1000 to have microsecond precision without result.

Is it possible to have microseconds precision with clock module, bios or another in CC3220SF board??

Thanks

  • 0
    Guru 39650 points

    Hi,

    Microsecond time precision with CC3220 not sounds much realistic. CC3220 have Cortex-M4 at 80MHz. It means you have 80 clock cycles in one microsecond ( in best case 80 one cycle instructions - see Cortex M4 instruction set infocenter.arm.com/.../index.jsp ).

    Jan

  • 0 in reply to Hnz
    Prodigy 30 points

    Hi Jan,

    thanks for the response. My goal is to synchronize two boards.

    You're right. In fact when I used the clock_gettime(CLOCK_REALTIME, &abstime) I had nanoseconds precision but it was a fake precision also in millisecond because I tryed to synchronize two launchxl board but whitout good result. 

    But using the  Clock_getTicks I have now good result with millisecond resolution. I have two board very accurate and synchronized in time.

    But the goal is to have microsecond precision and not millisecond,

    Regards

  • 0 in reply to Michele Bruno
    Guru 79975 points
    Hi,

    1ms ... 80000 clock cycles
    1us ... only 80 clock cycles

    For achieving best possible precision you should use hardware timers directly without abstraction layers from OS. General-Purpose Timers of CC3220 are described at www.ti.com/.../getliterature.tsp chapter 9.

    Jan