//fprintf(stderr,"Writing header len=%d\n", cmdlen);
//printb(buff,12);
r=usb_bulk_write(dev, 1, (char*)buff, 12, USB_TIMEOUT);
//fprintf(stderr,"Writing header len=%d\n", cmdlen);
//printb(buff,12);
r=usb_bulk_write(dev, 1, (char*)buff, 12, USB_TIMEOUT);