https://devzone.nordicsemi.com/f/nordic-q-a/80424/hardfault-when-sending-uart-data-over-nusHi all, As written above, as soon as I try to send an array of 8 bytes(8,255,0,1,64,64,0,1) onto the NUS the ble_nus_data_send and the consecutive sd_ble_gatts_hvx() trigger an hardfault which I am struggling to understand. In the call: ble_nus_data_senden-USTelligent Community 13Mon, 11 Oct 2021 07:22:18 GMThttps://devzone.nordicsemi.com/thread/333393?ContentTypeID=1Mon, 11 Oct 2021 07:22:18 GMT137ad170-7792-4731-bb38-c0d22fbe4515:97691816-c13f-4bb1-b9c0-d342c1ce1cffAndreaFont<p>That explains! Thank you!</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/333301?ContentTypeID=1Fri, 08 Oct 2021 15:05:31 GMT137ad170-7792-4731-bb38-c0d22fbe4515:c40a6242-df86-4ee2-b241-f114fda2267bSigurd[quote user="AndreaFont"]As I decreased the UART interrupt priority from MID to LOWEST the hardfault disappeared. Any clue why that happens?[/quote] <p><span>You can only call softdevice api from application interrupt priority 5 and lower:</span></p> <p><span><a href="https://infocenter.nordicsemi.com/topic/sds_s112/SDS/s1xx/processor_avail_interrupt_latency/exception_mgmt_sd.html">infocenter.nordicsemi.com/.../exception_mgmt_sd.html</a></span></p> <p><span></span></p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/333084?ContentTypeID=1Thu, 07 Oct 2021 13:41:22 GMT137ad170-7792-4731-bb38-c0d22fbe4515:9e45935f-93d2-4d1b-953f-c558cba7f58cAndreaFont<p>As I decreased the UART interrupt priority from MID to LOWEST the hardfault disappeared. Any clue why that happens?</p><div style="clear:both;"></div>