https://devzone.nordicsemi.com/f/nordic-q-a/5058/s120-interrupt-latencyWe have an NRF51822 running S120 at 32MHz. Our system has two removable batteries. If a battery is removed we need to switch to the other battery as fast as possible. We would like to do this in an interrupt service routine. ie detect battery failen-USTelligent Community 13Fri, 16 Jan 2015 16:27:56 GMThttps://devzone.nordicsemi.com/thread/17796?ContentTypeID=1Fri, 16 Jan 2015 16:27:56 GMT137ad170-7792-4731-bb38-c0d22fbe4515:c7291365-0504-453e-97dd-cb19cf6d5338Hung Bui<p>Hi Charles,</p> <p>I don&#39;t think we can do anything to reduce the 1400usec maximum latency.</p> <p>However, the idea of using the PPI is not a bad idea. You can use the PPI to connect the GPIO task with the event from the LPCOMP to detect the drop in the input voltage compare to a reference voltage. Please have a look at chapter 32 in the RM. But be aware that using PPI, GPIO task and LPCOMP will of course draw some extra current.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/17795?ContentTypeID=1Thu, 08 Jan 2015 04:27:31 GMT137ad170-7792-4731-bb38-c0d22fbe4515:43c5b77d-705d-439d-ab9d-22078e443701Charles Manning<p>I&#39;m thinking of an alternative here:</p> <p>Perhaps I can use the GPIOTE engine and the PPI to use the change on one pin to trigger the other. Does that sound plausible?</p><div style="clear:both;"></div>