https://devzone.nordicsemi.com/f/nordic-q-a/62415/nrf9160-at-interface-optionsHi, When nRF9160 is used as a co-processor and an external host MCU is used to interface with nRF9160, what are the serial interfaces that are allowed? The at_client example uses UART, is it possible to use SPI instead of UART? The at_client exampleen-USTelligent Community 13Thu, 11 Jun 2020 10:58:50 GMThttps://devzone.nordicsemi.com/thread/254440?ContentTypeID=1Thu, 11 Jun 2020 10:58:50 GMT137ad170-7792-4731-bb38-c0d22fbe4515:c47cc9a5-2db8-4c7f-88ef-2382aec9f808H&#229;kon Alseth<p>Hi,</p> <p>&nbsp;</p> <p>The at_client uses the library named at_host:</p> <p><a href="https://github.com/nrfconnect/sdk-nrf/blob/master/lib/at_host/at_host.c">https://github.com/nrfconnect/sdk-nrf/blob/master/lib/at_host/at_host.c</a></p> <p>&nbsp;</p> <p>which is initialized on boot up, which is the reason why main is empty:</p> <p><a href="https://github.com/nrfconnect/sdk-nrf/blob/master/lib/at_host/at_host.c#L308">https://github.com/nrfconnect/sdk-nrf/blob/master/lib/at_host/at_host.c#L308</a></p> <p>&nbsp;</p> <p>It does not support other transport layers than UART (UART0, 1 or 2) at this time, unfortunately.</p> <p>However; you can patch the at_host file, and add any other transport layer if you&#39;d like.</p> <p>&nbsp;</p> <p>Kind regards,</p> <p>Håkon</p><div style="clear:both;"></div>