Lexicon DC-2 - Manual (Page 7)

Lexicon, Inc.
DC-2/MC-1 Serial Communications Protocol
Printed on: 10/19/00
7 of 44
Data Link Header:
Byte Number
Description Value
First Byte(0) Start of Packet(SOP) 0xF1
Byte(1) DLL Data Count nn
Application Header:
Byte(2)
Command nn
Byte(3) APP Data Count(number of application data bytes to Follow) nn
Application Data:
Byte(4)
Data[0] nn
Byte(5) Data[1] nn
… Data[…] nn
Last Data Byte -1 Data[Data Count -1] nn
Data Link Tail:
Last Byte
End of Packet (EOP) 0xF2
6.1 Errors
If the number of DLL data bytes received is the same as the data count and an EOP has not been received,
the DC-2/MC-1 responds by transmitting a NAK packet with an error code
DC_ERR_INVALID_PACKET. The DC-2/MC-1 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.
7 Application Layer
7.1 DC-2/MC-1 Asynchronous Notification Packets
DC-2/MC-1 has been designed to transmit the asynchronous notification packets following these system
changes:
1. Power On
2. Entering Standby
3. Front Panel Display update and
4. Parameter Value Changes.
The notification packets are defined as follows:
7.1.1 Wakeup Notification
By transmitting the Wakeup Notification, DC-2/MC-1 indicates the unit has just “powered on” or reset and
is ready to receive host commands. If no acknowledgment is received within ACK_TIMEOUT, DC-2/MC-
1 will continue to operate. This notification is primarily for the HOST to know the status of the DC-2/MC-
1.
7.1.1.1 Notification Packet Description
Application Header:
Command
DC_WAKEUP 0x01
Data Count 0 0x00
Application Data:
N/A