Only For Training And Service Purposes - LG GM750 Service Manual

3. Technical Brief
3.12.2.3. 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.
Name
USBH_CLK
USBH_DIR
USBH_NEXT
USBH_STOP
USBH_DATA[0:7]
MSM7200A
USBH_DATA[0:7]
LGE Internal Use Only
Note
Input clock from PHY
Controls the direction of USBH_DATA. When high, data
is driven into the MSM.
Used by the PHY to throttle data.
Signals the end of a USB transmit packet or a register
write operation, and optionally stops any receive.
Bi-directional data pin
Table. HSUSB Signal Interface
PM7540
USBH_CS
USBH_CLK
USBH_DIR
ISP1508AET
USBH_NEXT
USBH_STOP
Figure. USB block (MSM7200A Side & ISP1508AET, MAX14526 Side)
USBH_DM
MAX14526
USBH_DP
- 60 - Copyright © 2009 LG Electronics. Inc. All right reserved.
DM
u-USB
DP
Connector.

Only for training and service purposes