https://devzone.nordicsemi.com/f/nordic-q-a/72709/nrf5340-bt-robustness-issue-with-xxx-qkaad0-siliconHi there, I have spent the last week trying to understand why my board, which is largely identical to the DK had various BT robustness issue; it was basically impossible to perform a DFU without a premature GATT_TIMEOUT; the exact same firmware on theen-USTelligent Community 13Mon, 15 Mar 2021 07:03:10 GMThttps://devzone.nordicsemi.com/thread/299637?ContentTypeID=1Mon, 15 Mar 2021 07:03:10 GMT137ad170-7792-4731-bb38-c0d22fbe4515:812b0f56-e8cb-4e6a-a661-bea78e7ffa4aKaja<p>I know you have to set the&nbsp;<a href="https://infocenter.nordicsemi.com/topic/ps_nrf5340/chapters/oscillators/doc/oscillators.html?cp=3_0_0_3_11_3_0#register.XOSC32MCAPS">XOSC32MCAPS</a>&nbsp;register.<br /><br />See&nbsp;<a href="https://infocenter.nordicsemi.com/topic/ps_nrf5340/chapters/oscillators/doc/oscillators.html?cp=3_0_0_3_11_0_0#concept_internal_caps">&quot;Using internal capacitors&quot;</a><br /><br />You can also have a look&nbsp;<a href="https://github.com/nrfconnect/sdk-hal_nordic/blob/8f013ea950f41bf69b18bf688bfb0dd80a3fdc44/nrfx/hal/nrf_oscillators.h#L75-L87">here</a></p> <p></p> <p>Best regards,<br />Kaja</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/299483?ContentTypeID=1Fri, 12 Mar 2021 13:19:14 GMT137ad170-7792-4731-bb38-c0d22fbe4515:bd95168c-962f-45ab-beaf-1692aa501226zigenz<p>A ha! That is a potential issue.</p> <p>I recall digging through the Zephyr bootstrapping code, but didn&#39;t see the obvious place/API for manipulating the HF load capacitance - certainly not obviously like the LF clock.</p> <p>Are you able to share some sample code and/or direct me to where in the NCS codebase I can find an example?</p> <p>Many thanks!</p> <p>BR,</p> <p>Z</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/299475?ContentTypeID=1Fri, 12 Mar 2021 13:11:41 GMT137ad170-7792-4731-bb38-c0d22fbe4515:fa323a7e-33ea-4dc4-8807-c2e7bff41349Kaja<p>The frequency accuracy is controlled by the HF clock.<br /><br />Best regards,<br />Kaja</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/299469?ContentTypeID=1Fri, 12 Mar 2021 12:45:38 GMT137ad170-7792-4731-bb38-c0d22fbe4515:71fdbe73-b49e-4bd0-a493-e944496d7267zigenz<p>Thanks Kaja.</p> <p>I will do as your suggested, however as a test, I switched over to the RC oscillator, set the tolerance to 500 ppm and observed the same issue. Is this what you would expect if there was indeed a frequency accuracy issue introduced by the xtal? Thanks.</p> <p>BR,</p> <p>Zyrus</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/299467?ContentTypeID=1Fri, 12 Mar 2021 12:36:39 GMT137ad170-7792-4731-bb38-c0d22fbe4515:a9ecf104-b260-41eb-90c3-bac3b0697d8aKaja<p>I would use a signal analyzer, see<a href="https://infocenter.nordicsemi.com/pdf/nwp_006.pdf?cp=16_18"> chapter 4&nbsp;</a>.<br /><br />Best regards,<br />Kaja</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/299465?ContentTypeID=1Fri, 12 Mar 2021 12:30:59 GMT137ad170-7792-4731-bb38-c0d22fbe4515:146313b1-1d66-4049-aedc-d92b57ed3e11zigenz<p>Hi Kaja,</p> <p>Performance is generally flaky for all use cases, but a DFU is nigh on impossible.</p> <p>As noted earlier, I have tested all variations of load caps with no appreciable difference.</p> <p>Can you please advise the most straightforward way to test the frequency accuracy of the carrier? Thanks!</p> <p>BR,</p> <p>Z</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/299456?ContentTypeID=1Fri, 12 Mar 2021 12:08:50 GMT137ad170-7792-4731-bb38-c0d22fbe4515:d3712d39-eec8-4541-a2c2-288d68515a3cKaja<p>Hi Z,<br /><br /><br />does this only happen for DFU?<br /><br />Have you checked the frequency accuracy of the carrier? Have you adjusted the internal load capacitors for the crystals?&nbsp;<br /><br />Best regards,<br />Kaja</p><div style="clear:both;"></div>