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 * Copyright (c) 2012, Texas Instruments Incorporated
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 *******************************************************************************
 * 
 *                       MSP430 CODE EXAMPLE DISCLAIMER
 *
 * MSP430 code examples are self-contained low-level programs that typically
 * demonstrate a single peripheral function or device feature in a highly
 * concise manner. For this the code may rely on the device's power-on default
 * register values and settings such as the clock configuration and care must
 * be taken when combining code from several examples to avoid potential side
 * effects. Also see www.ti.com/grace for a GUI- and www.ti.com/msp430ware
 * for an API functional library-approach to peripheral configuration.
 *
 * --/COPYRIGHT--*/
//******************************************************************************
//  MSP430F20xx Demo - Basic Clock, LPM3 Using WDT ISR, 32kHz ACLK
//
//  Description: This program operates MSP430 normally in LPM3, pulsing P1.0
//  at 4 second intervals. WDT ISR used to wake-up system. All I/O configured
//  as low outputs to eliminate floating inputs. Current consumption does
//  increase when LED is powered on P1.0. Demo for measuring LPM3 current.
//  ACLK = LFXT1/4 = 32768/4, MCLK = SMCLK = default DCO ~ 800kHz
//  //* External watch crystal installed on XIN XOUT is required for ACLK *//	
//
//
//           MSP430F20xx
//         ---------------
//     /|\|            XIN|-
//      | |               | 32kHz
//      --|RST        XOUT|-
//        |               |
//        |           P1.0|-->LED
//
//  M. Buccini / L. Westlund
//  Texas Instruments Inc.
//  September 2005
//  Built with CCE Version: 3.2.0 and IAR Embedded Workbench Version: 3.40A
//******************************************************************************

#include <msp430.h>

int main(void)
{
  BCSCTL1 |= DIVA_2;                        // ACLK/4
  WDTCTL = WDT_ADLY_1000;                   // WDT 1s/4 interval timer
  IE1 |= WDTIE;                             // Enable WDT interrupt
  P1DIR = 0xFF;                             // All P1.x outputs
  P1OUT = 0;                                // All P1.x reset
  P2DIR = 0xFF;                             // All P2.x outputs
  P2OUT = 0;                                // All P2.x reset

  while(1)
  {
    int i;
    P1OUT |= 0x01;                          // Set P1.0 LED on
    for (i = 5000; i>0; i--);               // Delay
    P1OUT &= ~0x01;                         // Reset P1.0 LED off
    __bis_SR_register(LPM3_bits + GIE);     // Enter LPM3
  }
}

#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=WDT_VECTOR
__interrupt void watchdog_timer (void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(WDT_VECTOR))) watchdog_timer (void)
#else
#error Compiler not supported!
#endif
{
    __bic_SR_register_on_exit(LPM3_bits);   // Clear LPM3 bits from 0(SR)
}