https://devzone.nordicsemi.com/f/nordic-q-a/86185/nrf5340-spis-csn-rise-time-specificationsHi, I have a nrf5340 SPIS peripheral being driven by an STM32H753 micro. Data transfer works fine except when I connect a scope probe to the CSN pin. With the scope probe connected, SPIS no longer generates interrupts. This happens with both a PicoScopeen-USTelligent Community 13Fri, 25 Mar 2022 11:49:24 GMThttps://devzone.nordicsemi.com/thread/359982?ContentTypeID=1Fri, 25 Mar 2022 11:49:24 GMT137ad170-7792-4731-bb38-c0d22fbe4515:3e7c3e0b-3e70-49dc-87f8-f17d67cec446Kenneth[quote user="skajam66"]Can you point me to any documentation on what the maximum (slowest) rise and fall time requirements are for a GPIO pin?[/quote] <p>There is no such limit, it will trigger on &gt;0.7*VDD or &lt;0.3*VDD.</p> <p>Kenneth</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/359976?ContentTypeID=1Fri, 25 Mar 2022 11:15:12 GMT137ad170-7792-4731-bb38-c0d22fbe4515:1d6d88ab-9f9c-44f5-b8f1-260dabca9e84skajam66<p>Hi Kenneth,</p> <p>The scope probe impedance is 1M ohm. The problem&nbsp;only occurs when the scope probe ground is connected to board ground.</p> <p>Can you point me to any documentation on what the maximum (slowest) rise and fall time requirements are for a GPIO pin?</p> <p>Regards,</p> <p>AC</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/359957?ContentTypeID=1Fri, 25 Mar 2022 09:51:40 GMT137ad170-7792-4731-bb38-c0d22fbe4515:6b3b9500-9fcf-4f0a-b5d5-bc3ae4817570Kenneth<p>Sounds very odd, scope probes are typically high impedance so they should not impact digital gpios much. I would look into whether you have also connected the ground of the probe to the ground of the board, before connecting the probe.&nbsp;</p> <p>Kenneth</p><div style="clear:both;"></div>