//******************************************************************************
//  MSP430-TEST44X Demo - USART0 UART 19200 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 = 1048576
//  Baud rate divider with 1048576hz = 1048576Hz/19200 ~ 55 (0036h)
//  //*An external watch crystal on XIN XOUT is required for ACLK*//	
//
//                MSP430F449
//             -----------------
//         /|\|              XIN|-
//          | |                 | 32768Hz
//          --|RST          XOUT|-
//            |                 |
//            |             P2.4|----------->
//            |                 | 19200 - 8N1
//            |             P2.5|<-----------
//
//  zhangchong
//  Lierda, Inc
//  February 2006.03
//  Built with IAR Embedded Workbench Version: 3.40A
//  ID：  MSP430-TEST44X
//  DATA：2005-7-12
//  REV： 2.0A
//  硬件連接如下：
//  1、PC機串口連接TEST44X學習板的9芯串行接口 J5_232
//  2、對撥動開關P_232、P1、U_USART，只有撥動開關 U_USART 的P2腳和P5腳撥到ON 的位置；
//  3、顯示數據如：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
  UTCTL0 = SSEL1;                       // UCLK = SMCLK
  UBR00 = 0x36;                         // 1MHz 19200
  UBR10 = 0x00;                         // 1MHz 19200
  UMCTL0 = 0x00;                        // no modulation
  UCTL0 = CHAR;                         // 8-bit character *SWRST*
  ME1 |= UTXE0 + URXE0;                 // Enable USART0 TXD/RXD
  IE1 |= URXIE0;                        // Enable USART0 RX interrupt
  P2SEL |= 0x30;                        // P2.4,5 = USART0 TXD/RXD
  P2DIR |= 0x10;                        // P2.4 output direction
  _EINT();                              // Enable interrupts

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

//interrupt[UART0RX_VECTOR] void usart0_rx (void)
#pragma vector=UART0RX_VECTOR
__interrupt void usart0_rx(void)
{
  while ((IFG1 & UTXIFG0) == 0);        // USART0 TX buffer ready?
  TXBUF0 = RXBUF0;                      // RXBUF0 to TXBUF0
}