GL852 USB 2.0 MTT HUB Controller
CHAPTER 1 GENERAL DESCRIPTION
GL852 is Genesys Logic’s premium 4-port Hub solution which fully complies with Universal Serial Bus
Specification Revision 2.0. GL852 implements multiple TT* (Note1) architecture that provide dedicated
TT* to each downstream (DS) ports, which guarantee Full-Speed(FS) data passing bandwidth when multiple
FS device perform heavy loading operations. The controller inherits Genesys Logic’s cutting edge
technology on cost and power efficient serial interface design. GL852 has proven compatibility, lower power
consumption figure and better cost structure above all USB2.0 hub solutions worldwide.
GL852 implements multiple hub configuration features onto internal mask ROM, which traditionally requires
one external EEPROM. The microprocessor detects general purpose I/O (GPIO) status during the initial stage
to configure hub settings such as (1) number of DSport, (2) declare of compound device (3)gang/individual
mode selection…etc. External EEPROM can be removed if no vendor specified PID/VID or product string
is required for the application.
GL852 supports four package types, summarized as below table. LQFP48 package provides full hub features
such as (1) two-color (green/amber) status LEDs for each DS ports,(2) Individual/Gang mode power
management scheme that indicates DS port over-current events. (3) Number of DS ports setting configured by
GPIO setting (4) non-removable declaration configured by GPIO setting (5) Support both 93C46 and 24C02
EEPROM (6) power switch polarity selections…etc. QFN28 package support only partial hub features but
provide smaller footprint (5x5mm) that targets space limited PCB layout environments such as embedded
system or UMPC/MID applications.
Package
type
# of DS
ports
4
Port #
config.
GPIO
Non-removable
Declaration
EEPROM
EEPROM/
GPIO
Power mgmt.
LED support
EEPROM
*64LQFP
Individual/Gang
Green/Amber
93C46
48LQFP
4
GPIO
Individual/Gang Green/Amber
93C46/ 24C02
*48QFN
28QFN
4
4
GPIO
GPIO
Individual/Gang
Individual/Gang
Green/Amber
No
93C46
24C02
EEPROM
EEPROM
GL852 package – feature summary
*Note 1: 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.
* Note 2: 64LQFP and 48QFN package types will be end of life (EOL) after existing customer migrate to
LQFP48 and 28QFN package, therefore not recommended for new designs.
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