1 Introducing EZ-USB
1.1
Introduction
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,
which gives the user a new level of convenience. For example:
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A USB device can be plugged in anytime, even when the PC is turned on.
When the PC detects that a USB device has been plugged in, it automatically inter-
rogates the device to learn its capabilities and requirements. From this informa-
tion, the PC automatically loads the device’s driver into the operating system.
When the device is unplugged, the operating system automatically logs it off and
unloads its driver.
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USB devices do not use DIP switches, jumpers, or configuration programs. There
is never an IRQ, DMA, MEMORY, or IO conflict with a USB device.
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USB expansion hubs make the bus available to dozens of devices.
USB is fast enough for printers, CD-quality audio, and scanners.
USB is defined in the Universal Serial Bus Specification Version 1.1 (http://usb.org), a
268-page document that describes all aspects of a USB device in elaborate detail. This
EZ-USB Technical Reference Manual describes the EZ-USB chip along with USB topics
that should provide help in understanding the Specification.
The Cypress Semiconductor EZ-USB is a compact integrated circuit that provides a
highly integrated solution for a USB peripheral device. Three key EZ-USB features are:
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The EZ-USB family provides a soft (RAM-based) solution that allows unlimited
configuration and upgrades.
The EZ-USB family delivers full USB throughput. Designs that use EZ-USB are
not limited by number of endpoints, buffer sizes, or transfer speeds.
The EZ-USB family does much of the USB housekeeping in the EZ-USB core,
simplifying code and accelerating the USB learning curve.
EZ-USB TRM v1.9
Chapter 1. Introducing EZ-USB
Page 1-1
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