User's Manual

Brooks Automation
52 260301 Revision A
7 Operation ATR60LF RFID Reader CAN Bus
7.5 Operation of the SECS Protocol Product Manual
7.5 Operation of the SECS Protocol
7.5.1 Introduction
The SECS-I standard defines a communication interface that is suitable for
exchanging messages between semiconductor processing equipment and a
host. A host is a computer or network of computers that exchanges
information with the equipment to perform/execute production.
The standard does not define the data contained within a message. The
meaning of messages must be determined through a message content
standard such as SEMI Equipment Communications Standard E5 (SECS-II).
This standard provides the means for independent manufacturers to
produce equipment and hosts that can be connected without requiring
specific knowledge of each other.
The SECS-I protocol can be seen as a layered protocol used for point-to -
point communication. The layers within SECS-I are the physical link, the
block transfer protocol and the message protocol.
The standard is not intended to meet the communication needs of all
possible applications. For example, the speed of RS232 may be insufficient
to meet the needs of transferring mass amounts of data or programs in a
short period, such as may be required for high-speed functional test
applications.
In a network, the roles of host and equipment may be assumed by any
party of the network. In this situation, one end of the communications link
must assume the role of the equipment and the other the role of the host.
Electronic Industries Association Standards:
EIA RS-232-C Interface between Data Terminal Equipment and Data
Communication Equipment Employing Serial Binary Data Interchange.
7.5.2 SECS-I Implementation
This message set describes the communication between a SECS-I reader
and a host. The host and the RFID reader communicate via an RS232
interface (SECS-I).
Character structure Data is transmitted or received in a serial bit stream of 10 bits per
character at one of the specified data rates. The standard character has one
start bit (0), 8 data bits and one stop bit (1). All bit transmissions are of the
same duration.
SECS-I performs no parity or other verification of the individual bytes.
Master-Slave The host connects to the reader. If there is a conflict, the host “gives in”
(i.e. receives before sending).
In the course of communication, the reader takes on the role of the master
and the host takes on the role of the slave.