User's Manual

General Software Information
6-15
<eom> - end of message, byte that specifies the end of
the message which is defined
as the ASCII character %.
Unsolicited Status Message
The MPI 6000 sends unsolicited status messages to the host as required for system
operation.
The host and the MPI 6000 uses the following serial communications unsolicited sta-
tus message as
shown here:
<som> <len> <msgSeqNum> <cmd> <cmdSeqNum> <status> [<data>] <crc16> <eom>
where
<som> - start of message, byte that specifies the start of the message which is defined
as the ASCII character &.
<le
n> - length, word that specifies the number of bytes in the entire mess
age.
<msgSeqNum> - message sequence number, byte that specifies the message
sequence
number of the message. See the software communication sequence number controls
section for details.
<cmd> - command, word that specifies the system c
ommand. See the command sec-
tions for details.
<cmdSeqNum> - command sequenc
e number, byte that specifies the command
sequence number of
the message. See the software communication sequence number
controls section for details.
<status> - status, word that specifies the system
status. See the response sections for
details.
[<data>] - optional data payload that varies in length from 0 to 63 bytes and is asso-
ciated with each specific response.
See the response sections for details.
<crc16>
- 16 bit cyclic redundancy check, word that specifies the 16
bit cyclic redun-
dancy check of the message exclusive of the <som> and <eom> byte
s. The polyno-
mial for the CRC calculation is X
16
+X
12
+X
5
+1 with a divisor polynomial of 1021H
and an initial value of FFFFH for a CCITT16 type CRC.
<eom> - end of message, byte that specifies the end of
the message which is defined
as the ASCII character %.
PRELIMINARY