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Set pin low every timer interval in hardware

Question asked by Karl Fraasch on Jul 16, 2020
Latest reply on Jul 22, 2020 by Sabina Bruce

I am interfacing to an external ADC using the RT1064. The particular ADC supports a "Request" pin which allows the user to pull the pin low to request an ADC sample. The software will then set the pin high once the sample is read using SPI.

My preference is to trigger the request pin entirely in hardware, to guarantee a precise sampling rate.

 

I have experimented using the PIT routed to the XBAR to trigger an IOMUX pin. While I am able to trigger a pulse at my desired rate, the pulse matches the shape of the PIT trigger. What I need is to pull the pin low every time the timer triggers. Software will then take care of setting the pin high once the operation is complete.

 

From what I can tell, this is not possible using XBAR with PIT (input) and IOMUX (output). Are there other XBAR inputs or outputs that can accomplish this (QTIMER, FLEXIO)? Or are there separate modules entirely other than XBAR to accomplish this (FLEXIO)?

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