What is the maximum scan rate on a digital pin?

Forums Forums Xcelerator Blocks What is the maximum scan rate on a digital pin?

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    If an advanced Xcelerator block were introduced to timestamp 30us events (yes, very tight).
    Can the current XLR8 board clock a block of VHDL fast enough to capture events on this order?
    Is the board designed well enough to function reliably at these kinds of speeds (controlled impedance of signal lines for example?

    I realize, that the intention was simplistic Arduino compatibility, but am curious how far into the extreme realm this board might go?


    A rate of 30 microseconds is actually quite slow compared to the hardware speed. It corresponds to a frequency of 33 KHz, while the base clock frequency is 16 MHz. This would allow about 480 clocks between timestamp events which is a long time in hardware. Beyond that, the XB logic can be run at a faster clock rate. The OpenXLR8 module also receives both a 32 MHz and a 64 MHz clock as well which could be used to run the logic even faster.

    In fact, OpenXLR8 includes a method to specify additional clocks at faster or slower rate, by modifying one extra file during the OpenXLR8 flow. This would allow one to run at an even faster rate of 128MHz or even faster. We’ll be publishing a new video soon that explains how to take advantage of this.

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