
Chapter 1. Introducing EZ-USB FX2 Page 1-1
Chapter 1 Introducing EZ-USB FX2
1.1 Introduction
The Universal Serial Bus (USB) has gained wide acceptance as the connection method of choice
for low and medium speed PC peripherals. Equally successful in the Windows and Macintosh
worlds, USB has delivered on its promises of easy attachment, an end to configuration hassles,
and true plug-and-play operation.
The second generation of the USB specification, “USB 2.0”, extends the original specification to
include:
• 480 Mbits/sec signaling rate, a 40× improvement over the USB 1.1 rate of 12 Mbits/sec.
• Full backward and forward compatibility with USB 1.1 devices and cables.
• A new hub architecture that can provide multiple 12 Mbits/sec downstream ports for USB
1.1 devices.
The Cypress Semiconductor EZ-USB FX2 (often abbreviated as “FX2” in this manual) is a single-
chip USB 2.0 peripheral whose architecture is similar to that of the Cypress Semiconductor EZ-
USB FX family. Although much of the FX architecture is preserved, certain elements have been
redesigned to accommodate the higher data rates offered by USB 2.0.
This introductory chapter begins with a brief USB tutorial to put USB and FX2 terminology into con-
text. The remainder of the chapter briefly outlines the FX2 architecture.
1.2 An Introduction to USB
Like a well-designed automobile or appliance, a USB peripheral’s outward simplicity hides internal
complexity. There’s a lot going on “under the hood” of a USB device.
• A USB device can be plugged in anytime, even while the PC is turned on.
• When the PC detects that a USB device has been plugged in, it automatically interrogates
the device to learn its capabilities and requirements. From this information, the PC auto-
Komentáře k této Příručce