I am moving my software from BF609 eval board into my target board. I have problem in setting-up USB clock. On eval board there is 48MHz oscillator and my software runs OK. However, on my target board there is 24MHz quartz. I verified on oscilloscope that it generates required frequency, but I am not able to set-up USB clock. For that purpose I updated USB_PLL_OSC register. Simply updating this register has no effect. I tried to modify PLLM field with value 20 instead of default 10. I was also trying to set the PLLMSEL field, also without success. Is anybody able to help me with this subject ?