//******************************************************************************
//  MSP430F54x Demo - FLL+, Runs Internal DCO at 2.45MHz with LFXT1 as Ref
//
//  Description: This program demonstrates setting the internal DCO to run at
//  2.45MHz with auto-calibration by the FLL+ circuitry. It uses LFXT1 as FLL
//  reference.
//  ACLK = LFXT1 = 32768Hz, MCLK = SMCLK = DCO = (74+1) x REFO = 2457600Hz 
//
//                MSP430F5438
//             -----------------
//        /|\ |              XIN|-
//         |  |                 | 32kHz
//         ---|RST          XOUT|-
//            |                 |
//            |            P11.1|--> MCLK = 2.45MHz
//            |                 |
//            |            P11.0|--> ACLK = 32kHz
//            |                 |
//
//  W. Goh
//  Texas Instruments Inc.
//  March 2009
//  Built with CCE v3.1 Build 3.2.3.6.4 & IAR Embedded Workbench Version: 4.11B
//******************************************************************************

#include "msp430x54x.h"

void main(void)
{
  WDTCTL = WDTPW + WDTHOLD;                 // Stop watchdog timer

  P1DIR |= BIT0;                            // P1.0 output
  P11DIR |= 0x07;                           // ACLK, MCLK, SMCLK set out to pins
  P11SEL |= 0x07;                           // P11.0,1,2 for debugging purposes.

  // Initialize LFXT1
  P7SEL |= 0x03;                            // Select XT1
  UCSCTL6 &= ~(XT1OFF);                     // XT1 On
  UCSCTL6 |= XCAP_3;                        // Internal load cap

  // Loop until XT1 fault flag is cleared
  do
  {
    UCSCTL7 &= ~XT1LFOFFG;                  // Clear XT1 fault flags
  }while (UCSCTL7&XT1LFOFFG);               // Test XT1 fault flag

  // Initialize DCO to 2.45MHz
  __bis_SR_register(SCG0);                  // Disable the FLL control loop
  UCSCTL0 = 0x0000;                         // Set lowest possible DCOx, MODx
  UCSCTL1 = DCORSEL_3;                      // Set RSELx for DCO = 4.9 MHz
  UCSCTL2 = FLLD_1 + 74;                    // Set DCO Multiplier for 2.45MHz
                                            // (N + 1) * FLLRef = Fdco
                                            // (74 + 1) * 32768 = 2.45MHz
                                            // Set FLL Div = fDCOCLK/2
  __bic_SR_register(SCG0);                  // Enable the FLL control loop

  // Worst-case settling time for the DCO when the DCO range bits have been
  // changed is n x 32 x 32 x f_MCLK / f_FLL_reference. See UCS chapter in 5xx
  // UG for optimization.
  // 32 x 32 x 2.45 MHz / 32,768 Hz = 76563 = MCLK cycles for DCO to settle
  __delay_cycles(76563);

  // Loop until XT1,XT2 & DCO fault flag is cleared
  do
  {
    UCSCTL7 &= ~(XT2OFFG + XT1LFOFFG + XT1HFOFFG + DCOFFG);
                                            // Clear XT2,XT1,DCO fault flags
    SFRIFG1 &= ~OFIFG;                      // Clear fault flags
  }while (SFRIFG1&OFIFG);                   // Test oscillator fault flag

  while(1)
  {
    P1OUT ^= BIT0;                          // Toggle P1.0
    __delay_cycles(600000);                 // Delay
  }
}