MSP430串口通信问题求救

只看该作者 · 2012-7-17 16:07

刚开始学430，遇到问题了。下面两个程序最终理论结果应该没区别吧！为什实际差别这么大？
程序一：
#include "msp430x14x.h"
#include "delay.h"
#define uchar unsigned char
#define uint  unsigned int
uchar const trdata[]={'A','B','C','D','E','F','G','H','I','J','K','L',0x0d,0x0a};
uchar i;
void main( void )
{
  // Stop watchdog timer to prevent time out reset
  WDTCTL = WDTPW + WDTHOLD;
  P3SEL|=0X30;
  ME1|=UTXE0+URXE0;
  UCTL0|=CHAR;
  UTCTL0|=SSEL0;
  UBR10=0X00;
  UBR00=0X03;
  UMCTL0=0X4a;//设置波特率为9600
  UCTL0&=~SWRST;
  IE1|=UTXIE0;
  while(1)
  {

for(i=0;i<14;i++)
{
   TXBUF0=trdata[i];
   while(!(IFG1&UTXIFG0));

}

//_BIS_SR(LPM3_bits+GIE);
  }
}
#pragma vector=UART0TX_VECTOR
__interrupt void usart0_rx(void)
{
  _BIC_SR_IRQ(LPM3_bits);
}    //结果是自动循环发送。

程序二：
#include "msp430x14x.h"
#include "delay.h"
#define uchar unsigned char
#define uint  unsigned int
uchar const trdata[]={'Z','h','a','n','g','H','U','a','q','i','n','g',0x0d,0x0a,0x00};
uchar i;
void main( void )
{
  // Stop watchdog timer to prevent time out reset
  WDTCTL = WDTPW + WDTHOLD;
  P3SEL|=0X30;
  ME1|=UTXE0+URXE0;
  UCTL0|=CHAR;
  UTCTL0|=SSEL0;
  UBR10=0X00;
  UBR00=0X03;
  UMCTL0=0X4a;//设置波特率为9600
  UCTL0&=~SWRST;
  IE1|=UTXIE0;
  while(1)
  {

while(trdata[i]!=0x00)
{
   TXBUF0=trdata[i];
   while(!(IFG1&UTXIFG0));
   //IFG1&=~UTXIFG0;
   i++;
}

// _BIS_SR(LPM3_bits+GIE);
  }
}
#pragma vector=UART0TX_VECTOR
__interrupt void usart0_rx(void)
{
  _BIC_SR_IRQ(LPM3_bits);
}                //结果是每按一次复位键，完整的发送一次。

求高手解释啊！！！！！