https://devzone.nordicsemi.com/f/nordic-q-a/4073/gpio-sense-intervalDear Nordic Developer Zone, I&#39;m using nrf51822 EK testing the GPIO sense function. The code I&#39;m using is based on what a nordic employee has posted elsewhere in this dev Zone. I configured PIN 0 as input sensing for low level. It worked but couldnen-USTelligent Community 13Wed, 15 Oct 2014 15:20:43 GMThttps://devzone.nordicsemi.com/thread/14617?ContentTypeID=1Wed, 15 Oct 2014 15:20:43 GMT137ad170-7792-4731-bb38-c0d22fbe4515:84fcf7e9-4ae0-45f7-bdb5-38836f6660ceTony.X<p>Yeah, it worked. But it stimulates me thinking what if I want to use not the buttons but a general GPIO pin then how should I config that pin. From what I&#39;ve known, those pins don&#39;t have pull_up/down resistors connected.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/14616?ContentTypeID=1Wed, 15 Oct 2014 15:13:26 GMT137ad170-7792-4731-bb38-c0d22fbe4515:2c3195f7-1aad-4e11-a09f-969caa6f6161Tony.X<p>I will try this out. Thanks for your advice. Cheers.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/14615?ContentTypeID=1Tue, 14 Oct 2014 00:52:49 GMT137ad170-7792-4731-bb38-c0d22fbe4515:37ca0289-2be0-4b0e-86df-c7f12714e05eRK<p>Yes your problem is here ..</p> <pre><code>| (NRF_GPIO_PIN_NOPULL &lt;&lt; GPIO_PIN_CNF_PULL_Pos) </code></pre> <p>The evaluation kit doesn&#39;t have pullup resistors on the buttons so when you release the button the voltage is just drifting slowly back up towards Vdd from 0 .. which in my experience takes about 1-2 seconds. You need NRF_GPIO_PIN_PULLUP.</p> <p>If you import the boards.h include and use the &#39;BUTTON_PULL&#39; define, it works for all boards because it&#39;s defined appropriately there for each one.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/14614?ContentTypeID=1Mon, 13 Oct 2014 16:14:38 GMT137ad170-7792-4731-bb38-c0d22fbe4515:6dcbace3-56c7-4934-9191-822b63053e95Tony.X<p>Thanks for your fast reply. It wasn&#39;t a __WFI before. Even without __WEF and __WFI, it has same issue.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/14613?ContentTypeID=1Mon, 13 Oct 2014 16:06:54 GMT137ad170-7792-4731-bb38-c0d22fbe4515:e835ca0f-c7d5-4d6a-aad4-5d5904df4977John<p>I don&#39;t know if this is the issue or not, but could you try a __WFE rather than a __WFI?</p><div style="clear:both;"></div>