MSP430 串口操作发送数据，PC读发生overrun 错误

我最近写一个读芯片数据通过串口发送给上位机，读到一个串口发送一个，上位机读取过程中发生An overrun error occurred during transfer. A character was not read from the hardware before the next character arrived.错误，

下面是我的设置，请问怎么设置可以避免上述错误？

void Init_Uart(void)
{
//Set UCSWRST
UCA1CTL1_bit.UCSWRST_A1 = 1;
UCA1CTL1 = 0x81;
UCA1BRW = 0x40;            //7.3728M 115200baud


//Config port
P4SEL |= BIT4 + BIT5;
//Clear UCSWRST
UCA1CTL1_bit.UCSWRST_A1 = 0;

//Enable interrupt
UCA1IE_bit.UCRXIE_A1 = 1;
UCA1IE_bit.UCTXIE_A1 = 0;
return;
}

uchar Uart_TxByte(uchar hexchar)
{
while (!UCA1IFG_bit.UCTXIFG_A1);
UCA1TXBUF = hexchar;
return hexchar;
}