https://devzone.nordicsemi.com/f/nordic-q-a/20346/does-the-nfc-type-4-library-globally-disable-interrupts-at-any-pointDoes the NFC library globally disable interrupts at any point? We&#39;re trying to track down an issue where our code occasionally misses an I2C event during NFC read/write.en-USTelligent Community 13Fri, 31 Mar 2017 14:11:08 GMThttps://devzone.nordicsemi.com/thread/79301?ContentTypeID=1Fri, 31 Mar 2017 14:11:08 GMT137ad170-7792-4731-bb38-c0d22fbe4515:77c22a2c-4e09-4f20-a41a-d0e6703dd19dCurtisHx<p>To answer my own question: No, the NFC Type 4 library does not globally disable interrupts.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/79300?ContentTypeID=1Mon, 20 Mar 2017 14:52:54 GMT137ad170-7792-4731-bb38-c0d22fbe4515:1f05d0b4-bdf3-470b-bffa-cd5ce1c102caCurtisHx<p>Thanks for the update. Turns out our problem was not related to the NFC Library disabling / enabling interrupts. It was caused by a timing problem in our code. Good to know about the NFC interrupts, though.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/79299?ContentTypeID=1Mon, 20 Mar 2017 14:34:30 GMT137ad170-7792-4731-bb38-c0d22fbe4515:6bf86427-83ed-4c86-b159-104d9e4585c2Michal<p>Yes, the NFC library can globally disable interrupts through nrf_drv_clock module, look for <code>CRITICAL_REGION_ENTER()</code> and <code>CRITICAL_REGION_EXIT()</code> macros (using critical sections for RMW operations on driver&#39;s state variables). The nrf_drv_clock is used for controlling oscillators. NFC can only be enabled when a high precession crystal oscillator is running.</p> <p>But even if IRQs are disabled, the I2C events should be set as pending and should fire when the interrupts are enabled again.</p><div style="clear:both;"></div>