test44x_uart11_38400.c

MSP430通信操作

//******************************************************************************
//  MSP430-TEST44X Demo - USART1 UART 38400 Echo ISR, DCO SMCLK
//
//  Description; Echo a received character, RX ISR used. Normal mode is LPM0,
//  USART1 RX interrupt triggers TX Echo.
//  ACLK = LFXT1 = 32768Hz,  MCLK = SMCLK = UCLK0 = DCOCLK = 1048576
//  Baud rate divider with 1048576hz = 1048576Hz/38400 ~ 27 (001Bh)
//  //*An external watch crystal on XIN XOUT is required for ACLK*//	
//
//                MSP430F449
//             -----------------
//         /|\|              XIN|-
//          | |                 | 32768Hz
//          --|RST          XOUT|-
//            |                 |
//            |             P4.0|----------->
//            |                 | 38400 - 8N1
//            |             P4.1|<-----------
//
//  zhangchong
//  Lierda, Inc
//  February 2006.03
//  Built with IAR Embedded Workbench Version: 3.40a
//  ID：  MSP430-TEST44X
//  DATA：2005-7-12
//  REV： 2.0A
//  硬件连接如下：
//  1、PC机串口连接TEST44X学习板的9芯串行接口 j5-232_1
//  2、对拨动开关P_232、P1、U_USART，只有拨动开关 P_232 的P2脚和P4脚拨到ON 的位置；拨动开关P1的P1脚和P2脚拨到ON的位置；
//  3、发送数据如：fe fe 68 10 01 00 00 00 00 00 00 01 03 1F 90 00 2c 16
//******************************************************************************

#include <msp430x44x.h>

void main(void)
{
  WDTCTL = WDTPW + WDTHOLD;             // Stop WDT
  FLL_CTL0 |= XCAP14PF;                 // Configure load caps
  UTCTL1 = SSEL1;                       // UCLK = SMCLK
  UBR01 = 0x1B;                         // 1MHz 38400
  UBR11 = 0x00;                         // 1MHz 38400
  UMCTL1 = 0x00;                        // no modulation
  UCTL1 = CHAR;                         // 8-bit character **SWRST**
  ME2 |= UTXE1 + URXE1;                 // Enable USART1 TXD/RXD
  IE2 |= URXIE1;                        // Enable USART1 RX interrupt
  P4SEL |= 0x03;                        // P4.0,1 = USART1 TXD/RXD
  P4DIR |= 0x01;                        // P4.0 output direction
  _EINT();                              // Enable interrupts

  for (;;)
  {
    _BIS_SR(CPUOFF);                    // Enter LPM0
    _NOP();                             // Required only for C-spy
  }
}

//interrupt[UART1RX_VECTOR] void usart1_rx (void)
#pragma vector=UART1RX_VECTOR
__interrupt void usart1_rx(void)
{
  while ((IFG2 & UTXIFG1) == 0);        // USART1 TX buffer ready?
  TXBUF1 = RXBUF1;                      // RXBUF1 to TXBUF0
}