请问为什么串口一定要连续发Tx_buffer的数据？

/***********************************************************************************************************************
* Function Name: r_sci1_callback_transmitend
* Description : This function is a callback function when SCI1 finishes transmission.
* Arguments : None
* Return Value : None
***********************************************************************************************************************/
static void r_sci1_callback_transmitend(void)
{
/* Start user code. Do not edit comment generated here */
R_SCI1_Serial_Send(Tx_buffer,10);
/* End user code. Do not edit comment generated here */
}

如果改成

/***********************************************************************************************************************
* Function Name: r_sci1_callback_transmitend
* Description : This function is a callback function when SCI1 finishes transmission.
* Arguments : None
* Return Value : None
***********************************************************************************************************************/
static void r_sci1_callback_transmitend(void)
{
/* Start user code. Do not edit comment generated here */

/* End user code. Do not edit comment generated  here */
}

则无法发送，这是想说一发就死循环不可么