https://devzone.nordicsemi.com/f/nordic-q-a/56801/need-help-on-setting-up-low-level-interrupt-handlerI&#39;m trying to get the most performance per mA out of my nRF52, for test purposes I&#39;ve used the nrfx libraries to communicate to the peripherals but I want to make my own. I’ve successfully created a TWI driver using the HAL library direct registeren-USTelligent Community 13Tue, 21 Jan 2020 10:02:18 GMThttps://devzone.nordicsemi.com/thread/230024?ContentTypeID=1Tue, 21 Jan 2020 10:02:18 GMT137ad170-7792-4731-bb38-c0d22fbe4515:33bc87dc-8916-4e80-a1e9-e4c1ee539e98T IJ<p>Well, as always I&#39;ve spoken too soon.</p> <p>After fiddling around I&#39;ve managed to get it working.</p> <p>I&#39;ve changed the NRFX_IRQ_XXX to</p> <p>NVIC_SetPriority(SPIM0_SPIS0_TWIM0_TWIS0_SPI0_TWI0_IRQn, p_config-&gt;interrupt_priority);<br /> NVIC_EnableIRQ(SPIM0_SPIS0_TWIM0_TWIS0_SPI0_TWI0_IRQn);</p> <p>And this made it work.&nbsp;</p> <p></p> <p>P.S. the 4k optimized is wrong, it is unoptimized. Optimized is 1.9k max which is still 3x as much as the bare code I&#39;ve written.</p> <p></p> <p>Kind Regards</p><div style="clear:both;"></div>