Kinetis MicrocontrollersのトピックRe: k64F precision pulse width measurement

k64F precision pulse width measurement

davenadler — Wed, 20 Dec 2017 20:23:53 GMT

Need to measure a short pulse.

Precision dictates this cannot be done using interrupts on pin transition; must use a hardware timer...

Using K64F timer hardware, what's the best way to measure an external pulse width?
Thanks!

Re: k64F precision pulse width measurement

Robin_Shen — Fri, 22 Dec 2017 02:16:31 GMT

Hi Dave,

Please refer the ftm dual_edge_capture demo in SDK_2.3.0_FRDM-K64F.
You can download the SDK_2.3.0_FRDM-K64F from MCUXpresso SDK Builder.

Best Regards,

Robin

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Re: k64F precision pulse width measurement

davenadler — Sat, 23 Dec 2017 01:34:42 GMT

Thanks Robin, I saw that. Dual-edge capture relies on the pulse width being within the timer duration (longer pulses will wrap to smaller values), and flex timer is only 16-bit resolution. How can I measure a wider range of pulse values and/or get higher resolution?
Thanks,
Best Regards, Dave

Re: k64F precision pulse width measurement

Robin_Shen — Mon, 25 Dec 2017 09:07:03 GMT

Maybe you can use the Timer Overflow Interrupt(TOF) to measure a wider range of pulse values.
Software count how many times the Timer Overflow Interrupt has happens.

For example:

Best Regards,

Robin