在lab4.c中有以下两条重要语句
cdcReceiveDataInBuffer(dataBuffer, BUFFER_SIZE, CDC0_INTFNUM);//接收
cdcSendDataInBackground(dataBuffer, bytesReceived,CDC0_INTFNUM, 0);//发送
在文件开头声明了:
#define BUFFER_SIZE 40
uint8_t dataBuffer[BUFFER_SIZE]; // User buffer to hold the data