check ep for data, add it to queue and sleep for interval

def _read(self):
        """ check ep for data, add it to queue and sleep for interval """
        while self._rxactive:
            try:
                rv = self._ep_in.read(self._ep_in.wMaxPacketSize)
                if self._isFTDI:
                    status = rv[:2] # FTDI prepends 2 flow control characters,
                    # modem status and line status of the UART
                    if status[0] != 1 or status[1] != 0x60:
                        log.info(
                            "USB Status: 0x{0:02X} 0x{1:02X}".format(
                                *status))
                    rv = rv[2:]
                for rvi in rv:
                    self._rxqueue.put(rvi)
            except usb.USBError as e:
                log.warn("USB Error on _read {}".format(e))
                return
            
            time.sleep(self._rxinterval)