（13）MSP430F5529 UART0 串口0通信

P3.3--RXD P3.4--TXD

#include <msp430f5529.h>
void main(void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop WDT
P3SEL |= BIT3+BIT4; // P3.3,4 = USCI_A0 TXD/RXD
UCA0CTL1 |= UCSWRST; // **Put state machine in reset**
UCA0CTL1 |= UCSSEL_2; // SMCLK
UCA0BR0 = 9; // 1MHz 115200 (see User's Guide)
UCA0BR1 = 0; // 1MHz 115200
UCA0MCTL |= UCBRS_1 + UCBRF_0; // Modulation UCBRSx=1, UCBRFx=0
UCA0CTL1 &= ~UCSWRST; // **Initialize USCI state machine**
UCA0IE |= UCRXIE; // Enable USCI_A0 RX interrupt
__bis_SR_register(LPM0_bits + GIE); // Enter LPM0, interrupts enabled
__no_operation(); // For debugger
}
// Echo back RXed character, confirm TX buffer is ready first
#pragma vector=USCI_A0_VECTOR
__interrupt void USCI_A0_ISR(void)
{
switch(__even_in_range(UCA0IV,4))
{
case 0:break; // Vector 0 - no interrupt
case 2: // Vector 2 - RXIFG
while (!(UCA0IFG&UCTXIFG)); // USCI_A0 TX buffer ready?
UCA0TXBUF = UCA0RXBUF; // TX -> RXed character
break;
case 4:break; // Vector 4 - TXIFG
default: break;
}
}