LG E900 Service Manual page 46

3.10.3 HS-USB
The universal serial bus (USB) is an interconnection standard widely supported by the electronic
industry. The USB2.0 spec defines data rates as low-speed (1.5 Mbps), full-speed (12Mbps) and hi-
speed (480 Mbps). When two devices are connected via a USB interface, one of the devices must act as
a host, and the other device must act as a peripheral. The host is responsible for initiating and
controlling traffic on the bus. The USB specification requires personal computers (PCs) to act as hosts,
and other devices such as printers, keyboards, mice, etc. to act as peripherals. The OTG supplement
creates a new class of devices called OTG devices. OTG devices can act as either hosts or peripherals,
depending upon how they are connected and/or used.
The MSM7200A device contains a new USB high-speed function that is based on a embedded UTMI+
core with a UTMI+ low pin interface (ULPI) compatible port. The MSM device's ULPI interface connects
to an external ULPI PHY chip to complete the design. The ULPI core embedded in the MSM along with
the PM7540 IC and a USB high-speed PHY IC provide support for the high-speed interface.
Copyright © 2010 LG Electronics. Inc. All right reserved.
Only for training and service purposes
Figure. USB block( QSD8650 internal phy )
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3. TECHNICAL BRIEF
LGE Internal Use Only