USB serial host code

#include "mbed.h"
#include "USBHostSerial.h"

DigitalOut led(LED1);
Serial pc(USBTX, USBRX);
int i;


int main() {
    pc.printf("\nMain started \r\n");
    USBHostSerial serial;
    char str[1];
    int len;
    while(1) {
        
        wait(1);
        
        pc.printf("Start\r\n");

        // try to connect a serial device
        while(!serial.connect())
        pc.printf("Trying to connect \r\n");
            wait(1);
        
        pc.printf("Connected \r\n");
        // in a loop, print all characters received
        // if the device is disconnected, we try to connect it again
        
        while (1) {
            serial.printf("*IDN?\r\n"); // send SCPI command

            led=!led;
            // if device disconnected, try to connect it again
            if (!serial.connected())
                break;
            i = 0;
            // print characters received
            while (serial.available()) {
                pc.printf("%c", serial.getc());
                i++;
                }
            pc.printf(" (%d)\r\n\n", i);
            wait(0.3);
            }
        }
}