GL850G USB 2.0 Low-Power HUB Controller
CHAPTER 1 GENERAL DESCRIPTION
GL850G is Genesys Logic’s advanced version Hub solutions which fully comply with Universal Serial Bus
Specification Revision 2.0. GL850 inherits Genesys Logic’s cutting edge technology on cost and power
efficient serial interface design. GL850G has proven compatibility, lower power consumption figure and
better cost structure above all USB2.0 hub solutions worldwide.
GL850G provide multiple advantages to simplify board level design that help achieve lowest BOM (bill of
material) for system integrator. GL850G integrated both 5V to 3.3V and 3.3V to 1.8V voltage drop regulator
into single chip, therefore no external LDO required. Also, GL850G’s power enable pin supports both
high-enable and low-enable power switch that provides better flexibility on component selection.
GL850G embeds an 8-bit RISC processor to manipulate the control/status registers and respond to the requests
from USB host. Firmware of GL850G will control its general purpose I/O (GPIO) to access the external
EEPROM and then respond to the host the customized PID and VID configured in the external EEPROM.
Default settings in the internal mask ROM is responded to the host without having external EEPROM.
GL850G is designed for customers with much flexibility. The more complicated settings such as PID, VID,
and number of downstream ports settings are easily achieved by programming the external EEPROM (Ref. to
Chapter 5).
Each downstream port of GL850G supports two-color (green/amber) status LEDs to indicate normal/abnormal
status. GL850G also support both Individual and Gang modes (4 ports as a group) for power management.
The GL850G is a full function solution which supports both Individual/Gang power management modes and
the two-color (green/amber) status LEDs. Please refer the table in the end of this chapter for more detail.
Number of downstream ports setting can be configured by IO setting in absence of EEPROM. (Ref. to Chapter
5)
To fully meet the cost/performance requirement, GL850G is a single TT hub solution for the cost requirement.
Genesys Logic also provides GL852 for multiple TT hub solution to target on systems which require higher
performance for full/low-speed devices, like docking station, embedded system … etc.. Please refer to GL852
datasheet for more detailed information.
*TT (transaction translator) is the main traffic control engine in an USB 2.0 hub to handle the unbalanced
traffic speed between the upstream port and the downstream ports.
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