https://devzone.nordicsemi.com/f/nordic-q-a/90501/what-is-the-expected-nrf5340-boot-up-timeA product I&#39;m working on uses an nRF5340 (actually a Fanstel BT40 module with an nRF5340 in it) with NCS v1.7.1. It&#39;s got an SPI slave connection (the nRF is the slave) to another processor, and we&#39;ve noticed that it takes about 1.5 seconds after poweren-USTelligent Community 13Mon, 01 Aug 2022 11:53:49 GMThttps://devzone.nordicsemi.com/thread/379519?ContentTypeID=1Mon, 01 Aug 2022 11:53:49 GMT137ad170-7792-4731-bb38-c0d22fbe4515:f108ca07-11b1-46e7-a76e-c7190c0b9c36Marte Myrvold<p>Hi Glen,</p> <p>32k xtal startup time is up to 500 ms. However, there are Kconfigoptions for clock start up policy that will affect this time available here:&nbsp;<a href="https://github.com/nrfconnect/sdk-zephyr/blob/v3.0.99-ncs1/drivers/timer/Kconfig.nrf_rtc#L37">https://github.com/nrfconnect/sdk-zephyr/blob/v3.0.99-ncs1/drivers/timer/Kconfig.nrf_rtc#L37</a>.</p> <p>Additionally, you can disable serial output to lower the startup time.</p> <p>Best regards,</p> <p>Marte</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/379331?ContentTypeID=1Fri, 29 Jul 2022 13:11:51 GMT137ad170-7792-4731-bb38-c0d22fbe4515:3211a692-e229-4fe6-b448-5be257faf5f0Marte Myrvold<p>Hi&nbsp;Glen,</p> <p>I will check this internally and get back to you.</p> <p>Best regards,</p> <p>Marte</p><div style="clear:both;"></div>