fet430_uart01_0115k.c

msp430开发c语言例程

//******************************************************************************
//  MSP-FET430P430 Demo - USART0 UART 115200 Echo ISR, DCO SMCLK 
//
//  Description; Echo a received character, RX ISR used. Normal mode is LPM0, 
//  USART0 RX interrupt triggers TX Echo. 
//  ACLK = LFXT1 = 32768Hz,  MCLK = SMCLK = UCLK0 = DCOCLK = 1048576Hz
//  Baud rate divider with 1048576hz = 1048576Hz/115200 ~ 9.1 (009h|08h)
//  //*An external watch crystal on XIN XOUT is required for ACLK*//	  
//              
//                MSP430FG439
//             -----------------
//         /|\|              XIN|-  
//          | |                 | 32kHz  
//          --|RST          XOUT|-
//            |                 |
//            |             P2.4|-----------> 
//            |                 | 115200 - 8N1
//            |             P2.5|<-----------
//
//       
//  M.Buccini
//  Texas Instruments, Inc
//  June 2004
//  Built with IAR Embedded Workbench Version: 2.21B
//******************************************************************************

#include <msp430xG43x.h>

void main(void)
{
  WDTCTL = WDTPW + WDTHOLD;             // Stop WDT
  FLL_CTL0 |= XCAP18PF;                 // Configure load caps
  P2SEL |= 0x30;                        // P2.4,5 = USART0 TXD/RXD
  ME1 |= UTXE0 + URXE0;                 // Enable USART0 TXD/RXD
  UCTL0 |= CHAR;                        // 8-bit character
  UTCTL0 |= SSEL1;                      // UCLK = SMCLK
  UBR00 = 0x09;                         // 1MHz 115200 
  UBR10 = 0x00;                         // 1MHz 115200
  UMCTL0 = 0x0A;                        // modulation
  UCTL0 &= ~SWRST;                      // Initialize USART state machine
  IE1 |= URXIE0;                        // Enable USART0 RX interrupt

  _BIS_SR(LPM0_bits + GIE);             // Enter LPM0 w/ interrupt
}

#pragma vector=UART0RX_VECTOR
__interrupt void usart0_rx (void)
{
  while (!(IFG1 & UTXIFG0));            // USART0 TX buffer ready?
  TXBUF0 = RXBUF0;                      // RXBUF0 to TXBUF0
}