#include "mbed.h"
#include "USBSerial.h"
DigitalOut blue_led(LED1);    // led

USBSerial serial;    //Virtual serial port over USB
Serial pc(USBTX, USBRX);
 
int main(void) {
    uint8_t buf[128];
    while(1)
    {
        serial.scanf("%s", buf);
        serial.printf("recv: %s", buf);
        pc.printf("recv: %s\r\n", buf);
        serial.printf("I am a virtual serial port\n");
        blue_led = !blue_led;    // just for watching the passing
    }
}