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RM57L843: The highest resolution of timer of RM57L843

Part Number: RM57L843

Could any one tell me the lowest clock RM57L843 counter can read?

I referred datasheet it shows that:

tw(EXTCLKIN)H EXTCLKhigh-pulse duration 6 ns

tw(EXTCLKIN)L EXTCLK low-pulse duration 6 ns

Dose it mean if I call timer with this external clock, I can count the number of pulse with 6ns resolution ?

  • Tuan,

    This specification applies directly to the external clock input pins/feature (EXTCLKIN1 and EXTCLKIN2). In some ways, the answer to your question is yes, in that this clock input can be selected as source for the RTI counters.

    However, I am not certain if this is the answer to your question. Specifically, this specification does not apply to NHET, eQEP, or eCAP inputs which each are timer modules. N2HET and eCAP can be used for edge capture and eQEP is for enhanced quadrature encoder implementations.

    N2HET timing specifications are given in section 7.6.3 of the datasheet.
    eCAP input timing characteristics are provide in section 7.2.4 of the datasheet.

    Thanks and Regards,

    Chuck Davenport

  • In reply to Chuck Davenport:


    thanks for your rep.

    I am not professional about the types of timer modules that you said, so I trust that telling you my application, is the best way.

    I would like to measure the time of difference of arrival of RF signal, whose velocity is 3x10^8 m/s with 6ns resolution of that timer.

    It will take a time to transmit from receiver to MCU and this time is much higher than signal transmission time. So with a timer with 6 ns, after subtracting communication transmission time, I can get signal transmission time 

  • In reply to Tuan Vu Phan:

    Hello Tuan,

    I apologize for the delay in response to your question. Have you been able to determine the answer to you question? Let me know if you still need an answer and I will look this up.

    In the meantime, have a look at this posts to see if they answer your question.

    e2e.ti.com/.../559628 (note the difference in system and VCLK max frequencies will mean difference in the actual values for the RM57).

    Thanks and Regards,

    Chuck Davenport