Released Rev. C 2000-1252-01 Page 181
VersaPort 2200 Technical Manual
Appendix B: Communications Software
ASCII Serial Text Interface
a
Syntax:
NOTE . . .
ASYST RECOMMENDS ADDING AN “ESC” CHARACTER (27 IN DECIMAL, OR HEX
1B)
IN FRONT OF EACH ASCII COMMAND SENT TO ELIMINATE LINE NOISE
INTERRUPTION BETWEEN THE HOST AND THE ASYST TOOL. COMMANDS SENT
TO THE ASYST TOOL WILL NOT BE TRUNCATED OR CASCADED WITH UNWANTED
GARBAGE PRECEDING THE “ESC” CHARACTER.
AN EXAMPLE OF THE FORMAT: <ESC>HCS HOME<CR><LF>
• All messages are made up of ASCII characters (exceptions: CR, LF and BELL).
• Command and data fields are separated by a space or comma. Redundant
spaces are ignored.
• All messages are terminated by a carriage return and line feed.
• If the echo option is turned on (Host communication option = 3), the Load Port will
echo every character received from the Host port for a Host to perform data
integrity check. This is a one-way echo that is applicable to messages initiated by
the Host only.
NOTE . . .
THE HOST SHOULD NOT ATTEMPT TO ECHO MESSAGES INITIATED BY THE LOAD
PORT REGARDLESS OF WHETHER THE ECHO OPTION IS TURNED ON OR NOT.
• All unrecognizable commands or format will be rejected with a bell (07).
• All commands and data are case sensitive. Only upper case characters are
allowed.
• An Escape character can be used to abort a command.
• There are no header or length bytes associated with a serial text message.
Checksum is available only if the checksum option (Host communication option =
5) is selected.
• With the text-checksum option interface, the checksum is two-byte binary data in
INTEL format (low byte first, then high byte) that operates on every character in
the message up to the line feed. The checksum should be placed after CR and
LF in the message.
Example: HCS AUTO (CR)(LF)(0x6E)(2)
where (0x6E) is the low order byte of the checksum, and
(2) is the high order byte of the checksum
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