User's Manual

Table Of Contents
MPI 6000 Multi-Protocol Reader System Guide
6-12
Data Acknowledge Message
The MPI 6000 after receiving command request messages from the host sends data
acknowledge messages to the host.
The host after receiving command response messa
ges, asynchronous resp
onse mes-
sages, software flow control messages and unsolicited status
messages from the MPI
6000 sends data acknowledge messages to the MPI 6000.
The host and the MPI 6000 uses the following serial communications data acknowl-
edge message as shown here:
<som> <len> <msgSeqNum> <cmd> <cmdSeqNum> <resp> <msgSeqNumAck> <crc16> <eom>
where
<som> - start of message, byte that specifies the start of the message which is defined
as the ASCII character &.
<len> -
length, word that specifies the number of bytes in the entire messa
ge.
<msgSeqNum> - message sequence number, byte that specifies the message sequenc
e
number of the message. See the software communication sequence number controls
section for details.
<cmd> - comma
nd, word that specifies
the system command. See the command sec-
tions for details.
<cmdSeqNum> - command sequence number, byte that specifies the command
sequenc
e number of the message. See the software communication sequence number
controls section for details.
<resp> - response, word that specifies the system response. See the response
sections
for details.
<msgSeqNumAck> -
message sequence number acknowledge
, byte that specifies the
message sequence number of the message being acknowledged. See the software
communication sequence number controls section 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 polynome 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 %.
Command Response Message
The MPI 6000 after receiving command request messages from the host sends com-
mand response messages to the host.
The host and the MPI 6000 uses the following serial communications command
response
message as shown here:
<som> <len> <msgSeqNum> <cmd> <cmdSeqNum> <resp> [<data>] <crc16> <eom>
PRELIMINARY