Data loss when sending to native USB port (SerialUSB)

Hardware Arduino Due
7

Thanks, that's useful... I'm not sure I'm using the instructions exactly right but the following seems to work:

void Serial_::accept(void)
{
  static uint8_t r=0;
  int t=__LDREXB(&r);
  if(t)return;
  if(__STREXB(1,&r))return;
         ring_buffer *buffer = &cdc_rx_buffer;
        uint32_t i = (uint32_t)(buffer->head+1) % CDC_SERIAL_BUFFER_SIZE;

        // if we should be storing the received character into the location
        // just before the tail (meaning that the head would advance to the
        // current location of the tail), we're about to overflow the buffer
        // and so we don't write the character or advance the head.
        while (i != buffer->tail) {
                uint32_t c;
                if (!USBD_Available(CDC_RX)) {
                        udd_ack_fifocon(CDC_RX);
                        break;
                }
                c = USBD_Recv(CDC_RX);
                // c = UDD_Recv8(CDC_RX & 0xF);
                buffer->buffer[buffer->head] = c;
                buffer->head = i;

                i = (i + 1) % CDC_SERIAL_BUFFER_SIZE;
        }
   r=0;      
}

(cmaglie - I just saw your code, looks good, I'll try it out)

It's not amazingly fast (I am getting a 7MByte file through in about 50s) but it is reliable - no diff in 50MBytes of testing so far :slight_smile: