各位专家，请问MSP430F249 的外部晶振在复位后默认是开启的吗？如不不是的话，为什么用GERACE生成的代码中为什么是这样的：
void BCSplus_graceInit(void)
{
/* USER CODE START (section: BCSplus_graceInit_prologue) */
/* User initialization code */
/* USER CODE END (section: BCSplus_graceInit_prologue) */
/*
* Basic Clock System Control 2
*
* SELM_2 -- XT2CLK/LFXTCLK
* DIVM_0 -- Divide by 1
* SELS -- XT2CLK when XT2 oscillator present. LFXT1CLK or VLOCLK when XT2 oscillator not present
* DIVS_0 -- Divide by 1
* ~DCOR -- DCO uses internal resistor
*
* Note: ~DCOR indicates that DCOR has value zero
*
*/
BCSCTL1 &= ~XT2OFF;
BCSCTL2 = SELM_2 | DIVM_0 | SELS | DIVS_0;
if (CALBC1_8MHZ != 0xFF) {
/* Adjust this accordingly to your VCC rise time */
__delay_cycles(100000);
// Follow recommended flow. First, clear all DCOx and MODx bits. Then
// apply new RSELx values. Finally, apply new DCOx and MODx bit values.
DCOCTL = 0x00;
BCSCTL1 = CALBC1_8MHZ; /* Set DCO to 8MHz */
DCOCTL = CALDCO_8MHZ;
}
/*
* Basic Clock System Control 1
*
* ~XT2OFF -- Enable XT2CLK
* ~XTS -- Low Frequency
* DIVA_0 -- Divide by 1
*
* Note: ~<BIT> indicates that <BIT> has value zero
*/
BCSCTL1 |= DIVA_0;
/* USER CODE START (section: BCSplus_graceInit_epilogue) */
/* User code */
/* USER CODE END (section: BCSplus_graceInit_epilogue) */
}，以上代码中没有等待外部晶振稳定的代码，像自己写F149的时钟初始化中要用到
do {
IFG1 &= ~OFIFG; // Clear OSC Fault flag
__delay_cycles(50000); // Time for flag to set again
} while (IFG1 & OFIFG); // Loop while OSC Fault flag is set
还请各位专家解释一下
