Data Link Layer; Errors; Application Layer; Mc-8 Asynchronous Notification Packets - Lexicon MC-8 V1.0 - SERIAL COMMUNICATIONS PROTOCOL DEFINITION REV 1-4 Manual

Lexicon, Inc.
MC-8 Serial Communications Protocol

5 Data Link Layer

The data link layer is used to define a transmission packet. The layer appends a header and tail that encloses the
transmitted application packet data. The data link header will contain the start of packet byte and count of bytes to
follow. The data link tail will contain the end of packet byte.
Data Link Header:
Byte Number
First Byte(0)
Byte(1)
Application Header:
Byte(2)
Byte(3)
Application Data:
Byte(4)
Byte(5)
...
Last Data Byte -1
Data Link Tail:
Last Byte

5.1 Errors

If the number of DLL data bytes received is the same as the data count and an EOP has not been received, the MC-8
responds by transmitting a NAK packet with an error code DC_ERR_INVALID_PACKET. The MC-8 then
continues to look for a SOP byte and will not process the erroneous application packet. The HOST can use this as an
indicator to retransmit the corrupted packet.
In addition, each byte of a packet must be received sequentially and within the INTER_PACKET_TIME. If any of
the bytes within a packet transmission exceeds the INTER_PACKET_TIME, the MC-8 will respond by transmitting
a NAK packet with an error code DC_ERR_INVALID_PACKET. The MC-8 then continues to look for a SOP byte
and will not process the erroneous application packet. The HOST can use this as an indicator to retransmit the
corrupted packet.

6 Application Layer

6.1 MC-8 Asynchronous Notification Packets

MC-8 has been designed to transmit the asynchronous notification packets following these system changes:
1. Power On
2. Entering Standby
3. Front Panel Display update
4. Parameter Value Changes.
© 2003 Lexicon, Inc. All rights reserved.
Description
Start of Packet (SOP)
DLL Data Count
Command
APP Data Count (number of application data bytes to
Follow)
Data[0]
Data[1]
Data[...]
Data[Data Count -1]
End of Packet (EOP)
Printed on: 04/01/03
Value
0xF1
nn
nn
nn
nn
nn
nn
nn
0xF2
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