Usb - Acer 7299sl Service Manual

1.4.1.12 USB ( Universal Serial Bus)
(1) Introduction:
The USB stand alones hub for monitor is designed to provide USB expandability in a PC system
and plug and play control of the monitor . The USB IC is used in a micro controller based
monitor and communicates with the monitor system over the I
Since the device is a compound USB device (hab function plus embedded function), the
embedded function appears as PORT1 to the hose system. The four expansion ports are
number 2 through 5.
(2) I 2 C Interface
The I 2 C bus is used to interface to an external micro-controller needed to control the operation
of the hub when the SUB chip need to communicate with the micro-controller if asserts an
interrupt signal.
status register on the SUB chip through I 2 C bus.
(3) USB device states
A USB device has several possible states. Some of these states are visible to the USB and the
host and others are internal to the USB device. The following diagram describes these states.
1-16
The micro-comptroller services this interrupt by reading the appropriate
API Confidential
No Copy/Reproduction Allowed
2
C serial bus hub.
7299sl Service Guide