MSP430AFE253: how to use the inner 12MHZ RC crystal of MSP430AFE253

Hi Herbert,

To operate the DCO at 12MHz, select 12MHz using the internal DCO calibration values as described in the UserGuide on page 633.

I don't have one of these MSP430 to test this example on, but see if this will get you running on 12MHz.

int main(void)
{
	WDTCTL = WDTPW | WDTHOLD;	// stop watchdog timer
	
	DCOCTL = 0;
	BCSCTL1 = CALBC1_12MHZ;
	DCOCTL = CALDCO_12MHZ;


	return 0;
}

When configured as an external crystal oscillator, the above watchdog program can work, but when configured as an internal crystal oscillator, it does not work, and the simulator simulation, the program is always in a dead loop, will not automatically restart due to the watchdog timeout.

At this point, the emulator keeps track of the variable value of the WDTCTL register, which is always 0x6904

//开启着门狗，并喂狗WDTCTL = WDT ARST 1000:
//进入死循环，自动重启while (1);