本程序是通过F340的uart0与PC进行串口通讯的例程，具体实现为当F340收 *从PC传来的数据后将数据原样回发给PC机 ,端口为RX＝P0.5，TX＝P0.4-This program is through the F340' s uart0 serial communication with PC for a routine, concrete realization of the closing* When the