本人菜鸟一枚，求高手指导程序时候有问题： #include  "msp430x47x4.h"
void usart();
void main(void)
{
  WDTCTL = WDTPW+WDTHOLD;                   // Stop WDT
  FLL_CTL0 |= XCAP14PF;                     // Configure load caps
  TACTL= TASSEL_1+ID_3 + MC_1+TACLR; //定时器A的时钟源选择ACLK，8分频，增计数模式
  CCTL0 = CCIE;                   //使能CCR0中断
  CCR0 = 2047;             //设定周期0.5               
  usart();
  P2DIR=0x02;
   _EINT();
   for(;;)
  { 
    _BIS_SR(CPUOFF);  
    _NOP();
  } }
void usart(void)
{
  UCA0CTL0 |= UCSWRST;
  UCA0CTL0 |= UCSSEL_1;                     // CLK = ACLK，32768HZ
  UCA0BR0 = 0x03;                           // 9600
  UCA0BR1 = 0x00;                           //
  UCA0MCTL = 0x4A;                          // Modulation
  P2SEL |= 0x30;                       // P2.4,5 = USCI_A0 RXD/TXD
  P2DIR|=0x10;
  IE2=UCA0RXIE+UCA0TXIE;
  UCA0CTL0 &= ~UCSWRST;                     // **Initialize USCI state machine**
} //  Echo back RXed character, confirm TX buffer is ready first
#pragma vector=TIMERA0_VECTOR
__interrupt void Timer_A (void)
{
  P2OUT^=0x02;
  //while ((IFG2 & UCA0TXIFG) == 0);
  UCA0TXBUF =0x01;                    // TX -> RXed character
 
}
此帖出自小平头技术问答