void Chip_USB_Init(void)
{
/* Set USB PLL input to main oscillator */
Chip_Clock_SetUSBPLLSource(SYSCTL_PLLCLKSRC_MAINOSC);
/* Setup USB PLL (FCLKIN = 12MHz) * 4 = 48MHz
MSEL = 3 (this is pre-decremented), PSEL = 1 (for P = 2)
FCLKOUT = FCLKIN * (MSEL + 1) = 12MHz * 4 = 48MHz
FCCO = FCLKOUT * 2 * P = 48MHz * 2 * 2 = 192MHz (within FCCO range) */
Chip_Clock_SetupUSBPLL(3, 1);
/* Powerup USB PLL */
Chip_SYSCTL_PowerUp(SYSCTL_POWERDOWN_USBPLL_PD);
/* Wait for PLL to lock */
while (!Chip_Clock_IsUSBPLLLocked()) {}
/* enable USB main clock */
Chip_Clock_SetUSBClockSource(SYSCTL_USBCLKSRC_PLLOUT, 1);
/* Enable AHB clock to the USB block. */
Chip_Clock_EnablePeriphClock(SYSCTL_CLOCK_USB);
/* power UP USB Phy */
Chip_SYSCTL_PowerUp(SYSCTL_POWERDOWN_USBPHY_PD);
/* Reset USB block */
Chip_SYSCTL_PeriphReset(RESET_USB);
}
void platform_early_init(void)
{
/* set up clocking for a board with an external oscillator */
Chip_SetupXtalClocking();
/* Set USB PLL input to main oscillator */
Chip_Clock_SetUSBPLLSource(SYSCTL_PLLCLKSRC_MAINOSC);
/* Setup USB PLL (FCLKIN = 12MHz) * 4 = 48MHz
MSEL = 3 (this is pre-decremented), PSEL = 1 (for P = 2)
FCLKOUT = FCLKIN * (MSEL + 1) = 12MHz * 4 = 48MHz
FCCO = FCLKOUT * 2 * P = 48MHz * 2 * 2 = 192MHz (within FCCO range) */
Chip_Clock_SetupUSBPLL(3, 1);
/* Powerup USB PLL */
Chip_SYSCTL_PowerUp(SYSCTL_POWERDOWN_USBPLL_PD);
/* Wait for PLL to lock */
while (!Chip_Clock_IsUSBPLLLocked()) {}
/* Set default system tick divder to 1 */
Chip_Clock_SetSysTickClockDiv(1);
/* start the generic systick driver */
arm_cm_systick_init(Chip_Clock_GetMainClockRate());
lpc_debug_early_init();
}
/* Setup system clocking */
STATIC void SystemSetupClocking(void)
{
volatile int i;
/* Powerup main oscillator */
Chip_SYSCTL_PowerUp(SYSCTL_POWERDOWN_SYSOSC_PD);
/* Wait 200us for OSC to be stablized, no status
indication, dummy wait. */
for (i = 0; i < 0x100; i++) {}
/* Set system PLL input to main oscillator */
Chip_Clock_SetSystemPLLSource(SYSCTL_PLLCLKSRC_MAINOSC);
/* Power down PLL to change the PLL divider ratio */
Chip_SYSCTL_PowerDown(SYSCTL_POWERDOWN_SYSPLL_PD);
/* Setup PLL for main oscillator rate (FCLKIN = 12MHz) * 4 = 48MHz
MSEL = 3 (this is pre-decremented), PSEL = 1 (for P = 2)
FCLKOUT = FCLKIN * (MSEL + 1) = 12MHz * 4 = 48MHz
FCCO = FCLKOUT * 2 * P = 48MHz * 2 * 2 = 192MHz (within FCCO range) */
Chip_Clock_SetupSystemPLL(3, 1);
/* Powerup system PLL */
Chip_SYSCTL_PowerUp(SYSCTL_POWERDOWN_SYSPLL_PD);
/* Wait for PLL to lock */
while (!Chip_Clock_IsSystemPLLLocked()) {}
/* Set system clock divider to 1 */
Chip_Clock_SetSysClockDiv(1);
/* Setup FLASH access to 3 clocks */
Chip_FMC_SetFLASHAccess(FLASHTIM_50MHZ_CPU);
/* Set main clock source to the system PLL. This will drive 48MHz
for the main clock and 48MHz for the system clock */
Chip_Clock_SetMainClockSource(SYSCTL_MAINCLKSRC_PLLOUT);
/* Set USB PLL input to main oscillator */
Chip_Clock_SetUSBPLLSource(SYSCTL_PLLCLKSRC_MAINOSC);
/* Setup USB PLL (FCLKIN = 12MHz) * 4 = 48MHz
MSEL = 3 (this is pre-decremented), PSEL = 1 (for P = 2)
FCLKOUT = FCLKIN * (MSEL + 1) = 12MHz * 4 = 48MHz
FCCO = FCLKOUT * 2 * P = 48MHz * 2 * 2 = 192MHz (within FCCO range) */
Chip_Clock_SetupUSBPLL(3, 1);
/* Powerup USB PLL */
Chip_SYSCTL_PowerUp(SYSCTL_POWERDOWN_USBPLL_PD);
/* Wait for PLL to lock */
while (!Chip_Clock_IsUSBPLLLocked()) {}
}
