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Preliminary User Guide, Rev. 2
February 1999
13
Lucent Technologies Inc. 7-1
USS-720
USB Device Driver
1 Introduction
This document describes the design and implemen-
tation of USS720.SYS, a
Windows
* WDM USB driver
developed by In-System Design, Inc. (Note that this
driver was written specifically to work with the In-
System Design USB Smart Cable. For vendor-
specific implementations, refer to the “Notes for
Developers” in the Introduction of this Information
Manual.) The purpose of USS720.SYS is to provide
bulk data transfers and a mapping layer for the
IEEE
†
1284 registers over the Universal Serial Bus inter-
face.
The purpose of this document is to:
■ Define how USS720.SYS will interact with the
Win-
dows
operating system components and the inter-
face layer to other device classes.
■ Provide a guide for using USS720.SYS.
Note: The USS-720’s Automatic Mode is recom-
mended for almost all applications. The drivers
included in the Lucent Technologies USS-720
Evaluation Kit use only Automatic Mode. Auto-
matic mode implements all negotiation hand-
shakes automatically for Compatibility, Nibble,
and ECP modes. In Register Mode, the user
must do the negotiations manually in software.
Register Mode can be useful when imple-
menting a nonstandard parallel port interface.
For more information on the
Windows
system-level
components, USB architecture, and 1284 hardware,
please refer to:
■
Microsoft Win32 SDK
(October 96 or later), avail-
able from
Microsoft
*.
■
WDM Driver Model Specification
, available from
Microsoft.
■
WDM USB Driver Specification
, available from
Microsoft.
■
USB Device Class Definition for Printing Devices,
from usb.org web site.
■
USS-720 USB-to-
IEEE
1284 Bridge
Preliminary
Data Sheet (DS98-393CMPR), available from
Lucent Technologies Microelectronics Group.
■ IEEE
Standard Signaling Method for a Bidirectional
Parallel Peripheral Interface for Personal Comput-
ers
(
IEEE
Standard 1284-1994)
Figure 1 provides a point of reference for directions
mentioned in this document.
5-6005.r2
Figure 1. Signal Directions
*
Windows
and
Microsoft
are registered trademarks of Microsoft
Corporation.
†
IEEE
is a registered trademark of The Institute of Electrical and
Electronics Engineers, Inc.
OUTPUT
DRIVER
INPUT
INPUT
OUTPUT
BULK OUT
BULK IN
HOST PC
USS-720 IN
PERIPHERAL
USB