https://devzone.nordicsemi.com/f/nordic-q-a/85440/decryption-on-fly-and-s1len-dependenciesHello ! I have found that error free decryption ( MIC error) on fly depends from S1LEN configuration value. S1LEN have valid range value for each radio mode 2Mbit 1-8 1Mbit 1-6 bit 500K 1-6 125K 1 only So I have set it to 1 and it work inen-USTelligent Community 13Tue, 08 Mar 2022 07:50:37 GMThttps://devzone.nordicsemi.com/thread/356761?ContentTypeID=1Tue, 08 Mar 2022 07:50:37 GMT137ad170-7792-4731-bb38-c0d22fbe4515:ceeaedbb-129c-4456-8b8c-150e62b52646Hiihtaja<p>Hi !</p> <p>This is problem, PS say it is optional and for future. But without proper S1LEN decryption on fly dosn&#39;t work.</p> <p>And reason is not known. CCM configuration set properly . Not so much variation there,</p> <p>But can you tell if encryption/decryption on fly MUST work if S1LEN = 0 ?</p> <p></p> <p>Regards,</p> <p>Eugene</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/356726?ContentTypeID=1Mon, 07 Mar 2022 23:00:14 GMT137ad170-7792-4731-bb38-c0d22fbe4515:cad8c0e6-2b6f-4646-b648-38b9017b088dSigurd<p>Hi,</p> <p>I assume you set the correct&nbsp;CCM Operation mode:<br /><img src="https://devzone.nordicsemi.com/resized-image/__size/640x480/__key/communityserver-discussions-components-files/4/7230.pastedimage1646694045697v1.png" alt=" " /></p> <p>The only reference to S1 in the CCM docs, is that it&#39;s reserved for future use.</p> <p><a href="https://infocenter.nordicsemi.com/topic/ps_nrf52840/ccm.html?cp=4_0_0_5_3_2#unique_2057001550">infocenter.nordicsemi.com/.../ccm.html</a></p> <p></p> <p><img src="https://devzone.nordicsemi.com/resized-image/__size/640x480/__key/communityserver-discussions-components-files/4/6644.pastedimage1646693980926v1.png" alt=" " /><br /><br /></p><div style="clear:both;"></div>