https://devzone.nordicsemi.com/f/nordic-q-a/123724/the-issue-of-timer-interrupt-delay-caused-by-filesystem-operationsAfter attempting to write data to the filesystem, my 125μs timer interrupt (highest priority) is delayed by tens to hundreds of microseconds. I enabled the following configuration and call settings_save_one to save the data. CONFIG_SETTINGS=y CONFIG_SETTINGS_NVSen-USTelligent Community 13Mon, 18 Aug 2025 14:28:32 GMThttps://devzone.nordicsemi.com/thread/545946?ContentTypeID=1Mon, 18 Aug 2025 14:28:32 GMT137ad170-7792-4731-bb38-c0d22fbe4515:42d4aa27-38ad-4a3f-a66b-4ecdb128ceb7Hung Bui<p>Hi Lee,&nbsp;<br />What you observed is most likely because of the CPU stalling when doing a write/erase to flash.&nbsp;<br />&nbsp;It takes some time to write a word in flash (~50us AFAIK). So there will be a chance of additional latency when you do flash activity and having a timer interrupt.&nbsp;</p> <p>One solution I can think of is to move your interrupt handler into&nbsp;FLPR core&nbsp;and run it on SRAM.&nbsp;<br />Or you will have to split the critical period that all the flash activity has to wait until the critical period is finished.&nbsp;</p><div style="clear:both;"></div>