topic Re: MIMXRT1051: What is the minimum asynchronous input pulse width for GPIO pins? in i.MX RT Crossover MCUs

MIMXRT1051: What is the minimum asynchronous input pulse width for GPIO pins?

kyle_remich — Thu, 24 Oct 2019 14:36:05 GMT

I see the minimum input transition times in the basic datasheet but could not find the specific minimum input pulse width for a GPIO pin.

Re: MIMXRT1051: What is the minimum asynchronous input pulse width for GPIO pins?

victorjimenez — Tue, 29 Oct 2019 21:31:49 GMT

Hello Kyle,

You are right, we don't have this information on the datasheet. I'm currently checking with the design team if we have this data.

Regards,

Victor

Re: MIMXRT1051: What is the minimum asynchronous input pulse width for GPIO pins?

victorjimenez — Thu, 07 Nov 2019 22:16:08 GMT

Hello Kyle,

To give you more accurate support, could you please share more information about what you are trying to accomplish? For example, are you trying to prevent accidental detection (in case unintended pulses occur on the pin longer than the min time)?

Regards,

Victor

Re: MIMXRT1051: What is the minimum asynchronous input pulse width for GPIO pins?

kyle_remich — Mon, 25 Nov 2019 20:48:05 GMT

Hey Victor,

We are currently relying on the MIMXRT1051 to be able to sense a pulse of 50 us in order to shut off circuitry in an over-current situation. As you can imagine this is a safety concern. As it is still relatively early in the design phase and in the next spin there will be a hardware and software shut off in an over-current situation. However, in this ECB spin of the board we do not have the hardware shut off and I would like to confirm that it can sense a pulse at 50 us.

Thanks,

Kyle

Re: MIMXRT1051: What is the minimum asynchronous input pulse width for GPIO pins?

victorjimenez — Wed, 27 Nov 2019 19:01:09 GMT

Hello Kyle,

Thanks for sharing more information! Since you are trying to measure a pulse of a specific time, the best way to achieve this is to use a timer along with a pin in input capture mode. I recommend you using the quad timer for this purpose. In the SDK you will find an example named qtmr_inputcapture_outputpwm. This example first measures the duration of a pulse with the input capture mode and then outputs a PWM. I highly recommend you refer to this example to see how to make the input capture configuration.

Have a great day,
Victor

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