[转]MSP430另一种UART实现

  1 #include "msp430g2553.h"
  2 
  3 typedef unsigned char uchar;
  4 typedef unsigned int  uint;
  5 
  6 #define LED     BIT0
  7 #define TXD     BIT1                            // TXD on P1.1
  8 #define RXD    BIT2                             // RXD on P1.2
  9 #define POUT    P1OUT
 10 
 11 #define BITTIME_1b       13*4    //1bit宽度
 12 #define BITTIME_1b5      13*6    //1.5bit宽度
 13 
 14 uchar   bitcnt;
 15 uint    uart_buf;
 16 int    Send_flag;
 17 
 18 uchar  *str=" Hello EEWorld!  \r";
 19 
 20 void FaultRoutine(void)
 21  {
 22    while(1);                                 // 异常挂起
 23  }
 24 
 25 void ConfigClocks(void)
 26  {
 27  if (CALBC1_1MHZ ==0xFF || CALDCO_1MHZ == 0xFF)
 28    FaultRoutine();                            // If calibration data is erased
 29                                              // run FaultRoutine()
 30   BCSCTL1 = CALBC1_1MHZ;                     // Set range
 31   DCOCTL = CALDCO_1MHZ;                      // Set DCO step + modulation
 32   BCSCTL3 |= LFXT1S_2;                      // LFXT1 = VLO
 33   IFG1 &= ~OFIFG;                           // Clear OSCFault flag
 34   BCSCTL2 = 0;                               // MCLK = DCO = SMCLK
 35  }
 36 
 37 void ConfigPins(void)
 38  {
 39   P1DIR |= TXD+LED;
 40   P1DIR &= ~RXD;                    // P1.3 input, other outputs
 41   P1OUT |= TXD;                                  // clear output pins
 42 
 43  }
 44 
 45 
 46 //发送一个字节
 47 void send_char(uchar tchar)
 48 {
 49   TACTL = TACLR + TASSEL_2 + ID_3;              //选择SMCLK时钟;清TAR
 50   CCR0 = BITTIME_1b5;                    //crr0定时间隔为1bit时间宽度
 51   CCTL0 |= CCIE;                        //打开CCR0中断
 52   bitcnt = 10;                           //待发送的位数
 53   uart_buf = 0x0100;                     //8+N+1
 54   uart_buf |= tchar;                  //stop bit and start bit;
 55   uart_buf <<=1;
 56   Send_flag = 0;
 57   TACTL |= MC_1;                        //Start TA, UP mode.
 58   _BIS_SR(GIE);
 59   while(!Send_flag);                   //wait until send complete
 60   Send_flag = 1;
 61 }
 62 
 63 //发送一个字符串
 64 void send_String(uchar *tstr)
 65 {
 66   while(*tstr)
 67     send_char(*tstr++);
 68 }
 69 
 70 
 71 void send_IRQ(void)
 72 {
 73   if(bitcnt>0)
 74   {
 75     if(uart_buf & 0x01)
 76       POUT |= TXD;
 77     else
 78       POUT &= ~TXD;
 79     uart_buf >>= 1;
 80     bitcnt--;
 81   }
 82   else
 83   {
 84     TACTL &= ~MC_3;                    //Close the TA when a Byte send over.   ??
 85     CCTL0 &= ~CCIE;                    //关闭CCR0中断
 86     Send_flag = 1;
 87   }
 88 
 89 }
 90 
 91 
 92 
 93 void main( void )
 94 {
 95   // Stop watchdog timer to prevent time out reset
 96   uint i;
 97 
 98 
 99 
100   WDTCTL = WDTPW + WDTHOLD;
101   ConfigClocks();
102   ConfigPins();
103 
104 
105   while(1)
106   {
107    send_String(str);
108 
109    for(i=50000;i>0;i--);
110    for(i=50000;i>0;i--);
111    for(i=50000;i>0;i--);
112    for(i=50000;i>0;i--);
113    POUT ^= LED; // 翻转LED
114   }
115 }
116 
117 // Timer A0 interrupt service routine
118 #pragma vector=TIMER0_A0_VECTOR
119 __interrupt void Timer_A (void)
120 {
121 
122 
123    send_IRQ();
124 }
posted @ 2012-08-18 16:22  sky1991  阅读(620)  评论(3编辑  收藏  举报