https://devzone.nordicsemi.com/f/nordic-q-a/100597/hf-and-lf-clock-for-nrf52840Hello team, We are building a product using nrf52840 and zephyr stack. We have one external crystal 32MHz for HF clock. By default, the zephyr enables the internal RC oscillator(HFINT) to generate the HF clock. What is the right way to enable theen-USTelligent Community 13Fri, 09 Jun 2023 13:24:54 GMThttps://devzone.nordicsemi.com/thread/430259?ContentTypeID=1Fri, 09 Jun 2023 13:24:54 GMT137ad170-7792-4731-bb38-c0d22fbe4515:a6e943d1-c238-4ef3-9bd0-6b8fccb6c43fBrinda Pathak<p>Thanks much! That helped me.&nbsp;</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/429993?ContentTypeID=1Thu, 08 Jun 2023 12:37:16 GMT137ad170-7792-4731-bb38-c0d22fbe4515:31a43fc3-75ee-4733-86f9-be0b3c9c6104Vidar Berg<p>Hello&nbsp;<span>Brinda,</span></p> <p><span>HFINT is used by default, but the protocol stacks will automatically request the HFXO source when higher clock accuracy is needed (e.g., when using the RADIO) and release it again when it is no longer needed. It is possible to request the HFXO from the application and keep it active, but doing so will have a negative impact on your idle current (idle current with HFXO active is typ. around 200 uA).<br /></span></p> [quote user=""]The board does not have external crystal for LF. So we have two options to generate LF.[/quote] <p>Using the synthesized clock will also result in an increased idle current because it is derived from the HF clock source (prevents it from being released in System ON idle). The RC oscillator is generally the recommended choice for designs that don&#39;t include the LF crystal.&nbsp;</p> <p><span>Kconfig symbol to select RC as the LF clock source:</span></p> <div> <div><span>CLOCK_CONTROL_NRF_K32SRC_RC=y</span></div> <div><span></span></div> <div><span>Best regards,</span></div> <div><span>Vidar</span></div> </div><div style="clear:both;"></div>