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F5时钟问题



用的5438A

DCO采用默认设置,也就是默认1.048MHz频率不变,SMCLK、MCLK采用DCODIV,ACLK设置为使用DCODIV。量一下频率,发现三个时钟都变成了263kHz左右的频率,不是1MHz了。这是为什么呢?

程序:

 WDTCTL = WDTPW + WDTHOLD;
  P11SEL |= 0x07;
  P11DIR |= 0x07;
  P4OUT &=~ 0x01;
  P4DIR |= 0x01;

 UCSCTL4 |= SELA__DCOCLK;  
 
  while (1)
  {P4OUT ^= 0x01;
  __delay_cycles(60000);
  }

  • John C Smith,

    请用下面的例程再测试一下,看看结果怎么样?

    #include <msp430.h>

    int main(void)
    {
    WDTCTL = WDTPW+WDTHOLD; // Stop WDT
    P1DIR |= BIT0; // P1.0 output
    P11DIR |= 0x07; // ACLK, MCLK, SMCLK set out to pins
    P11SEL |= 0x07; // P11.0,1,2 for debugging purposes.

    while(1)
    {
    P1OUT ^= BIT0; // Toggle P1.0
    __delay_cycles(60000); // Delay
    }
    }