https://devzone.nordicsemi.com/f/nordic-q-a/62827/nrf52810-pwm-driver-frequency-is-not-stableUsing PWM control 2.7KHZ buzzer, it can work normally when I don&#39;t turn on the broadcast. Every time I turn on the radio, the buzzer seems to blend in with different frequencies, making it sound more than just a sound. The phenomenon occurs during broadcastingen-USTelligent Community 13Mon, 22 Jun 2020 09:04:55 GMThttps://devzone.nordicsemi.com/thread/256135?ContentTypeID=1Mon, 22 Jun 2020 09:04:55 GMT137ad170-7792-4731-bb38-c0d22fbe4515:ae2986a6-ecfc-4aa9-86a5-799ca63df46atsy19950218<ul> <li> <p class="src grammarSection">Thank you very much. It bothered me for a long time</p> </li> </ul><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/256133?ContentTypeID=1Mon, 22 Jun 2020 09:03:53 GMT137ad170-7792-4731-bb38-c0d22fbe4515:c38c78a9-dd28-4bca-88ae-9982333581d5tsy19950218<p><em><span class="skip">thank you very much for your help</span></em></p> <ul> <li> <p class="src grammarSection">I added sd_clock_hfclk_request when starting PWM.</p> </li> <li> <p class="src grammarSection">I added Ssd_clock_hfclk_release at the end of THE PWM.</p> <p class="src grammarSection">Solved the problem successfully.Thank you for bothering me for a long time</p> </li> </ul> <p><em></em></p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/256125?ContentTypeID=1Mon, 22 Jun 2020 08:34:20 GMT137ad170-7792-4731-bb38-c0d22fbe4515:5feda8be-1c15-4286-bc9a-2b9ce63bb330haakonsh<p>It&#39;s probably the switch from the internal 64MHz RC oscillator(HFINT) to the 32MHz external crystal(HFXO).&nbsp;<br /><br />I suggest you keep the HFXO on when driving the buzzer.&nbsp;<br /><br />See&nbsp;<a href="https://infocenter.nordicsemi.com/topic/ps_nrf52810/clock.html?cp=4_5_0_4_3">CLOCK — Clock control</a>&nbsp;and&nbsp;<a title="sd_clock_hfclk_request" href="https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s112.api.v7.0.1/group___n_r_f___s_o_c___f_u_n_c_t_i_o_n_s.html?cp=4_7_0_1_2_6_2_3#ga3e5afb495a1b0307c749cc268df94a74">sd_clock_hfclk_request</a>.&nbsp;<br /><br />Do you have a scope of the buzzer signal when you are in the two states?</p><div style="clear:both;"></div>