sdo.py 文件源码

def send(self, b, end=False):
        """Send up to 7 bytes of data.

        :param bytes b:
            0 - 7 bytes of data to transmit.
        :param bool end:
            If this is the last data.
        """
        assert len(b) <= 7, "Max 7 bytes can be sent"
        if not end:
            assert len(b) == 7, "Less than 7 bytes only allowed if last data"
        self._seqno += 1
        command = self._seqno
        if end:
            command |= NO_MORE_BLOCKS
            self._done = True
            # Change expected ACK:ed sequence
            self._blksize = self._seqno
            # Save how many bytes this message contains since this is the last
            self._last_bytes_sent = len(b)
        request = bytearray(8)
        request[0] = command
        request[1:len(b) + 1] = b
        self.sdo_client.send_request(request)
        self.pos += len(b)
        if self.crc_supported:
            # Calculate CRC
            self._crc = binascii.crc_hqx(b, self._crc)
        if self._seqno >= self._blksize:
            # End of this block, wait for ACK
            self._block_ack()