STRASBAUGH, INC.
7AF SECS/GEM Interface Ver. 1.9 February 19, 2002 3-1
Strasbaugh Confidential
3-1
3. Introduction
This document describes the SECS interface provided on the 7AF.
3.1 SECS Standard
The SEMI Equipment Communication Standard (SECS) is published by Semiconductor Equipment and Materials
International (SEMI). It defines a computer to computer communications interface between a unit of factory Equipment
and a Host Computer.
This Equipment complies to the complete SECS-I standard, and to the generic portions of the SECS-II standard, and
implements an appropriate subset of the SECS-II standard messages. The 7AF complies to the following versions of
standards:
1. E4-0298 (SECS-I)
Note: There were no changes to the SEMI E4 standard for 1993.
2. E50298 (SECS-II)
3.2 SECS-I Clarifications
The Equipment was designed to avoid using any of the unusual features of the SECS standard, so as to simplify the job of
implementing Equipment support on the Host. This section clarifies the Equipment/Host SECS interface.
3.2.1 Physical Connection
The 7AF provides a female 25-pin RS-232 "DB25F" connector on its back panel as the SECS port. The following pins on
the RS-232 connector are used:
Table 1 SECS Connector Pin Assignment.
Pin No. Description
3 RX Data (Host-to-Equipment).
2 TX Data (Equipment-to-Host).
7 Signal Ground.
20 Data Terminal Ready (DTR). The Equipment raises this output signal when
activating SECS. This is not required by the SECS standard, but you may find it
useful for modem control.
4 Request to send (RTS). The Equipment raises this output signal when activating
SECS. Not required by SECS standard, but you may find it useful for modem
control.
Optional SECS power pins are not provided. A pin is not provided for shield. It is recommended that the SECS cable’s
shield be connected to its back-shell.
3.2.2 SECS-I Blocks Transmitted
The Equipment uses the following SECS-I conventions in the blocks it sends:
1. The Device ID is present in every block, with the R-bit always set to "1".
2. The Block Number is always one (0x0001) for the first block of a message.
3. For Primary messages, the System Bytes are generated unique for each message. For Secondary messages, the
System Bytes are replicated from the received Primary message.
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