Page 108 - DCAP303_MULTIMEDIA_SYSTEMS

Multimedia Systems

notes UsB 1.1
• USB 1.1: Released in August 1998. Fixed problems identified in 1.0, mostly relating to hubs.
Earliest revision to be widely adopted.
UsB 2.0
The Hi-Speed USB Logo

• USB 2.0: Released in April 2000.
Added higher maximum bandwidth of 480 Mbit/s (60 MB/s) (now called “Hi-Speed”). Further
modifications to the USB specification have been done via Engineering Change Notices (ECN).
The most important of these ECNs are included into the USB 2.0 specification package available
from USB.org:
• Mini-A and Mini-B Connector ECN: Released in October 2000.
Specifications for Mini-A and B plug and receptacle. Also receptacle that accepts both plugs
for On-the-Go. These should not be confused with Micro-B plug and receptacle.
• Errata as of December 2000: Released in December 2000.

• Pull-up/Pull-down Resistors ECN: Released in May 2002.
• Errata as of May 2002: Released in May 2002.
• Interface Associations ECN: Released in May 2003.

New standard descriptor was added that allows multiple interfaces to be associated with
a single device function.
• Rounded Chamfer ECN: Released in October 2003.

A recommended, compatible change to Mini-B plugs those results in long lasting
connectors.
• Unicode ECN: Released in February 2005.

This ECN specifies that strings are encoded using UTF-16LE. The USB 2.0 did specify that
Unicode is to be used but it did not specify the encoding.
• Inter-Chip USB Supplement: Released in March 2006.

• On-the-Go Supplement 1.3: Released in December 2006.
USB On-the-Go makes it possible for two USB devices to communicate with each other
without requiring a separate USB host. In practice, one of the USB devices acts as a host
for the other device.
• Battery Charging Specification 1.1: Released in March 2007 (Updated 15 April 2009).
Adds support for dedicated chargers (power supplies with USB connectors), host chargers
(USB hosts that can act as chargers) and the No Dead Battery provision which allows
devices to temporarily draw 100 mA current after they have been attached. If a USB device
is connected to dedicated charger, maximum current drawn by the device may be as high
as 1.8 A. (Note that this document is not distributed with USB 2.0 specification package
only USB 3.0 and USB On-the-Go.)
• Micro-USB Cables and Connectors Specification 1.01: Released in April 2007.

• Link Power Management Addendum ECN: Released in July 2007.
This adds a new power state between enabled and suspended states. Device in this state is
not required to reduce its power consumption. However, switching between enabled and

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