MSP430FR5989 UART串口初始化的问题

void UCA0_uart_init()

{

P2OUT &= ~(BIT0+BIT1);

P2DIR  &= ~(BIT0+BIT1);

P2REN &= ~(BIT0+BIT1);

P2SEL0 |= BIT0 + BIT1;

P2SEL1 &= ~(BIT0 + BIT1);

UCA0CTLW0 |= UCSWRST | UCSSEL__ACLK;  // Put eUSCI in reset, select ACLK; when ACLK = 32768

UCA0BR0 = 0x03; // 32000/9600 = 3.333     波特率9600

UCA0BR1 = 0x00;

UCA0MCTLW |= 0x4900;

UCA0CTL1 &=~ UCSWRST; // release from reset

UCA0IE |= UCRXIE; // Enable RX interrupt

}

的电压，发现TxD管脚的电压为高电平3.0V，RxD管脚悬空状态（电压一会0V，一会0.8V），请问这样正常吗，串口RxD管脚配置成这样有什么问题吗？