+ /* Switch USB PLL source to system osc so we can power down the IRC */
+ lpc_scb.usbpllclksel = (LPC_SCB_USBPLLCLKSEL_SEL_SYSOSC << LPC_SCB_USBPLLCLKSEL_SEL);
+ lpc_scb.usbpllclkuen = (0 << LPC_SCB_USBPLLCLKUEN_ENA);
+ lpc_scb.usbpllclkuen = (1 << LPC_SCB_USBPLLCLKUEN_ENA);
+ while (!(lpc_scb.usbpllclkuen & (1 << LPC_SCB_USBPLLCLKUEN_ENA)))
+ ;
+