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5739 XT1不起振

Zheng Zhao1
Expert 1021 points
Other Parts Discussed in Thread: MSP430FR5739

在XIN XOUT上接了4M的晶振.按下面配置

  PJSEL0 |= BIT4+BIT5;      // Enable xin xout

  CSCTL0_H = 0xA5;
  CSCTL1 |= DCOFSEL0 + DCOFSEL1;             // Set max. DCO setting    8MHZ
  CSCTL2 = SELA_0 + SELS_3 + SELM_3;        // set ACLK = XT1; MCLK = DCO
  CSCTL3 = DIVA_0 + DIVS_0 + DIVM_0;        // set all dividers
  CSCTL4 |= XT1DRIVE_0;
  CSCTL4 &= ~XT1OFF;

do
  {
    CSCTL5 &= ~XT1OFFG;
                                            // Clear XT1 fault flag
    SFRIFG1 &= ~OFIFG;
  }while (SFRIFG1&OFIFG);                   // Test oscillator fault flag

这是例程里面的..

但是不起振,一直出现XT1OFG...

但是置位了XT1BYPASS位以后却通过了,但BYPASS位不是旁路么,旁路了晶振就直接变成了时钟源???按理说不应该置位啊;;;

  • 0
    TI__Intellectual 2865 points

    之前做过一个4MHZ外置晶振的例子，

    请看下面代码：

    #include "msp430fr5739.h"

    unsigned int tt = 0;
    unsigned char RXData = 0;
    unsigned char TXData = 0;
    unsigned char check = 0;
    void main(void)
    {
    WDTCTL = WDTPW + WDTHOLD; // stop watchdog

    // XT1 Setup

    PJSEL0 |= BIT4 + BIT5;

    CSCTL0_H = 0xA5;
    CSCTL1 |= DCOFSEL1 | DCOFSEL0; // Set max. DCO setting
    CSCTL2 = SELA_0 + SELS_0 + SELM_0; // set ACLK = XT1; MCLK = DCO
    CSCTL3 = DIVA_0 + DIVS_0 + DIVM_0; // set all dividers

    CSCTL4 |= XT1DRIVE_0 | XTS;
    CSCTL4 &= ~XT1OFF;

    do
    {
    CSCTL5 &= ~XT1OFFG;
    // Clear XT1 fault flag
    SFRIFG1 &= ~OFIFG;
    }while (SFRIFG1&OFIFG); // Test oscillator fault flag

    // Configure UART 0
    UCA0CTL1 |= UCSWRST;

    // Configure UART pins
    P2SEL1 |= BIT0 + BIT1;
    P2SEL0 &= ~(BIT0 + BIT1);
    UCA0CTL1 = UCSSEL_1;
    UCA0BR0 = 6;
    UCA0BR1 = 0;
    UCA0MCTLW |= (0x00 << 8) | 0x02 | UCOS16;

    UCA0CTL1 &= ~UCSWRST;

    while(1)
    {
    while (!(UCA0IFG&UCTXIFG));
    while(UCA0STATW & UCBUSY);
    UCA0TXBUF = 0x50;
    for(tt=0;tt<1000;tt++);

    while (!(UCA0IFG&UCTXIFG));
    while(UCA0STATW & UCBUSY);
    UCA0TXBUF = 0x55;
    for(tt=0;tt<1000;tt++);

    while (!(UCA0IFG&UCTXIFG));
    while(UCA0STATW & UCBUSY);
    UCA0TXBUF = 0x38;
    for(tt=0;tt<1000;tt++);

    while (!(UCA0IFG&UCTXIFG));
    while(UCA0STATW & UCBUSY);
    UCA0TXBUF = 0x50;
    for(tt=0;tt<1000;tt++);

    while (!(UCA0IFG&UCTXIFG));
    while(UCA0STATW & UCBUSY);
    UCA0TXBUF = 0x51;
    for(tt=0;tt<1000;tt++);

    while (!(UCA0IFG&UCTXIFG));
    while(UCA0STATW & UCBUSY);
    UCA0TXBUF = 0x52;
    for(tt=0;tt<1000;tt++);

    while (!(UCA0IFG&UCTXIFG));
    while(UCA0STATW & UCBUSY);
    UCA0TXBUF = 0x53;
    for(tt=0;tt<1000;tt++);

    while (!(UCA0IFG&UCTXIFG));
    while(UCA0STATW & UCBUSY);
    UCA0TXBUF = 0x54;
    for(tt=0;tt<1000;tt++);

    while (!(UCA0IFG&UCTXIFG));
    while(UCA0STATW & UCBUSY);
    UCA0TXBUF = 0x55;
    for(tt=0;tt<1000;tt++);

    while (!(UCA0IFG&UCTXIFG));
    while(UCA0STATW & UCBUSY);
    UCA0TXBUF = '\r';
    for(tt=0;tt<1000;tt++);

    while (!(UCA0IFG&UCTXIFG));
    while(UCA0STATW & UCBUSY);
    UCA0TXBUF = '\n';
    for(tt=0;tt<1000;tt++);
    }
    }