//******************************************************************************
//  MSP-FET430P410 Demo - LFXT1 Oscillator Fault Detection
//
//  Description: System runs normally in LPM3 with the basic timer clocked by
//  32kHz ACLK with a 1 second interrupt. P5.1 is normally toggled every
//  1 second inside basic timer interrupt. If an LFXT1 oscillator fault occurs,
//  NMI is requested forcing exit from LPM3. P5.1 is toggled rapidly by software
//  as long as LFXT1 oscillator fault is present. Assumed only LFXT1 as NMI
//  source - code does not check for other NMI sources.
//  ACLK = LFXT1 = 32768, MCLK = SMCLK = DCO = 32xACLK
//  //*External watch crystal on XIN XOUT is required for ACLK*//	
//
//
//            MSP430F413
//         ---------------
//     /|\|            XIN|-
//      | |               | 32kHz
//      --|RST        XOUT|-
//        |               |
//        |           P5.1|-->LED
//
//  M. Buccini
//  Texas Instruments Inc.
//  Feb 2005
//  Built with CCE Version: 3.2.0 and IAR Embedded Workbench Version: 3.21A
//******************************************************************************
#include <msp430x41x.h>

volatile unsigned int i;

void main(void)
{
  WDTCTL = WDTPW + WDTHOLD;                 // Stop WDT
  FLL_CTL0 |= XCAP14PF;                     // Configure load caps
  IE2 |= BTIE;                              // Enable BT interrupt
  BTCTL = BT_ADLY_1000;                     // 1s Interrupt
  P5DIR |= 0x02;                            // P5.1 output

  // An immedate Osc Fault will occur next
  IE1 |= OFIE;                              // Enable Osc Fault

  while(1)
  {
    _BIS_SR(LPM3_bits + GIE);               // Enter LPM3 w/ interrupts
    P5OUT ^= 0x02;                          // Toggle P5.1 using exclusive-OR
  }
}

// Basic Timer interrupt service routine
#pragma vector=BASICTIMER_VECTOR
__interrupt void basic_timer(void)
{
  P5OUT ^= 0x02;                            // Toggle P5.1 using exclusive-OR
}

#pragma vector=NMI_VECTOR
__interrupt void nmi_ (void)
{
  do
  {
    IFG1 &= ~OFIFG;                         // Clear OSCFault flag
    for (i = 0xFFF; i > 0; i--);            // Time for flag to set
    P5OUT ^= 0x02;                          // Toggle P5.1 using exclusive-OR
  }
  while ((IFG1 & OFIFG));                   // OSCFault flag still set?
  IE1 |= OFIE;                              // Enable Osc Fault
}