https://devzone.nordicsemi.com/f/nordic-q-a/4768/app-high-interrupt-latencyHi, I have application where I drive LEDs with shift registers. I need to send 14 bytes via SPI every 200us while I am in BLE connection. Timing should be exact as shift reg STROBE signal is taking place every 200us. I think to use Timer1 to generateen-USTelligent Community 13Wed, 10 Dec 2014 13:04:58 GMThttps://devzone.nordicsemi.com/thread/16867?ContentTypeID=1Wed, 10 Dec 2014 13:04:58 GMT137ad170-7792-4731-bb38-c0d22fbe4515:3ed5348f-1837-4485-8345-66c2febb6c75Stefan Birnir Sverrisson<p>As specified in the S110 SDS, BLE connection event blocks the CPU from approximately 1ms-6ms, depending on the number of packets sent in each connection event. Even though you are not sending any payload data, BLE protocol will send empty packets to maintain the connection. A BLE connection event with no payload data will still block the CPU for ~800us.</p> <p>The above is true for the second revision nRF51 hardware. For the Third revision hardware and S110 v7.1.0, shorter blocking time is possible. How to unblock the CPU and enable the short CPU time is described on <a href="https://devzone.nordicsemi.com/question/18751/how-to-unblock-the-cpu-during-connection-intervals-with-s110-v710/">this thead</a>. To identify the nRF51 hardware revision is described on <a href="https://devzone.nordicsemi.com/question/18925/nrf51822-revision/">this thread</a>. <a href="https://devzone.nordicsemi.com/question/21615/realtime-interrupt-with-50us-processing-possible-with-s110/">This thread</a> might also be helpful.</p> <p>There will soon be released a new S110 SDS which will specify the CPU blocking times for 3rd revision nRF51 hardware.</p> <p>To know when BLE advertising/connection events take place, there are some pointers on <a href="https://devzone.nordicsemi.com/question/22612/detect-if-code-has-been-interrupted-by-softdevice/?answer=22678#post-id-22678">this thread</a>.</p><div style="clear:both;"></div>