test44x_clks2.c

ADC12操作 DATA FLASH操作 EEPROM操作 FLASH读写操作 LCD点阵操作 TIMER_A_操作 Timer_B操作 比较器A操作 端口操作 基

//******************************************************************************
//  MSP430-TEST44X Demo - FLL+ clock, 32k xtal + HF xtal + internal DCO
//
//  Description This program demostrates using an external 32khz crystal to
//  supply the internal ACLK, and using a high speed crystal or resonator to
//  supply SMCLK. The MLCK for the CPU is supplied by the DCO.  The 32khz
//  crystal connects to pins Xin and Xout. The high frequency crystal or
//  resonator connects to pins XT2in and XT2out. The DCO clock is generated
//  internally and calibrated by the 32khz crystal. The resulting ACLK is
//  brought out on I/O pin P1.5, SMCLK is brought out on P1.4, and MCLK is
//  brought out on I/O pin P1.1.
//  Note:
//  External matching capacitors must be added for the high speed crystal or瑞雪兆
//  resonator as required.
//
//                 MSP430F44x
//             -----------------
//        /|\ |              XIN|-
//         |  |                 | 32kHz crystal
//         ---|RST          XOUT|-
//            |                 |
//            |                 |
//            |            XT2IN|-
//            |                 | HF XTAL or resonator (add capacitors)
//            |           XT2OUT|-
//            |                 |
//            |             P1.5|--> ACLK = 32khz crystal out
//            |                 |
//            |             P1.4|--> SMCLK = high freq xtal or resonator out
//            |                 |
//            |             P1.1|--> MCLK = DCO frequency
//            |                 |
//            |                 |
//  zhangchong
//  Lierda, Inc
//  February 2006.03
//  Built with IAR Embedded Workbench Version: 3.40a
//  ID：  MSP430-TEST44X
//  DATA：2005-7-12
//  REV： 2.0A
//  程序功能：该程序是通过设置不同的时钟源输出模式，具体是P1.5=ACLK=32.768k;
//            P1.4=SMCLK=1Mhz; P1.1=MCLK=1Mhz,通过本实验了解MSP430内部的时钟源。
//  硬件连接：在必须连接P1.1,P1.4,P1.5短接器，
//
//******************************************************************************
#include "msp430x44x.h"

void main(void)
{
  unsigned int i;

  WDTCTL = WDTPW + WDTHOLD;       // stop watchdog timer
  FLL_CTL0 = XCAP18PF;            // set load capacitance for 32k xtal
  FLL_CTL1 = FLL_CTL1 & ~XT2OFF;  // clear bit = high freq xtal on

  do                              // loop until flag is clear
  {
    FLL_CTL0 = FLL_CTL0 & ~XT2OF; // clear high freq oscillator fault flag
    for (i = 50000; i; i--);      // delay for crystal to start and FLL to lock
  }
  while (FLL_CTL0 & XT2OF);       // test high freq oscillator fault flag

                                  // if flag remained clear then -
  FLL_CTL1 = SELS;                // switch SMCLK = HF xtal
  P1DIR = 0x32;                   // P1.1, P1.4 & P1.5 to outputs
  P1SEL = 0x32;                   // P1.1, P1.4 & P1.5 functions to output
                                  // MCLK, SMCLK & ACLK
  while(1);                       // loop in place
}