/* Configure the crystal type connected to the device. 
Configure the crystal type connected between the OSCO and OSCI pins by writing the appropriate value to the XTAL field in SYSCTL_RCC. The PLL parameters are automatically adjusted in hardware to provide a PLL clock of 400MHz. */
void rcc_configure_xtal(enum xtal_t xtal)
/* Configure the crystal type connected to the device. 
Configure the crystal type connected between the OSCO and OSCI pins by writing the appropriate value to the XTAL field in SYSCTL_RCC. The PLL parameters are automatically adjusted in hardware to provide a PLL clock of 400MHz. */
void rcc_configure_xtal(enum xtal_t xtal)
{
	uint32_t reg32;
	reg32 = SYSCTL_RCC;
	reg32 &= ~SYSCTL_RCC_XTAL_MASK;
	reg32 |= (xtal & SYSCTL_RCC_XTAL_MASK);
	SYSCTL_RCC = reg32;
}