TransCore MPI6000A 用户手册

General Software Information

6-13

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 message.

<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 command. See the command sec-

tions for details.

<cmdSeqNum>

- command sequence number, byte that specifies the command

sequence 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.

[<data>]

- optional data payload that varies in length from 0 to 63 bytes and is associ-

ated 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> bytes. The polyno-
mial for the CRC calculation is X

+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 %.

Asynchronous Response Message

The MPI 6000 after receiving command request messages from the host optionally

sends asynchronous response messages to the host.
The host and the MPI 6000 uses the following serial communications asynchronous

response message as shown here: