GENERAL DESCRIPTION

GL850 is a 4-port standard Universal Serial Bus (USB) hub controller complies with Universal Serial Bus Specification Revision 2.0. GL850 can be connected to an USB1.1 host/hub or an USB2.0 host/hub. When GL850 is connected to an USB1.1 host/hub, it works just like an USB1.1 hub; the upstream port will operate in full-speed (FS) and the downstream port can operate in full-speed or low-speed (LS). When GL850 is connected to an USB2.0 host/hub, it works as an USB2.0 hub; the upstream port will operate in high-speed (HS) and the downstream port can operate in high-speed, full-speed, or low-speed. The bandwidths of high speed, full speed, and low speed are 480 Mbps, 12 Mbps, and 1.5 Mbps respectively.

FEATURES

• Compliant to USB specification Revision 2.0
− 4 downstream ports
− Upstream port supports both high-speed (HS) and full-speed (FS) traffic
− Downstream ports support HS, FS, and low-speed (LS) traffic
− 1 control pipe (endpoint 0, 64-byte data payload) and 1 interrupt pipe (endpoint 1, 1-byte data payload)
− Backward compatible to USB specification Revision 1.1
• On-chip 8-bit micro-processor
− RISC-like architecture
− USB optimized instruction set
− Dual cycle instruction execution
− Performance: 6 MIPS @ 12MHz
− With 64-byte RAM and 2K internal ROM
− Support customized PID, VID by reading external EEPROM
− Support downstream port configuration by reading external EEPROM
• Single Transaction Translator (TT) architecture
− Single TT shares the same TT control logics for all downstream port devices. This is the most cost effective solution for TT
• Each downstream port supports two-color status indicator, with automatic and manual modes compliant to USB specification Revision 2.0
• Support both individual and gang modes of power management and over-current detection for downstream ports
• Conform to bus power requirements
• Automatic switching between self-powered and bus-powered modes
• Integrated USB2.0 transceiver
• 0.35um CMOS technology
• PLL embedded with external 12 MHz crystal
• Operate on 3.3 Volts
• Improved output drivers with slew-rate control for EMI reduction
• Internal power-fail detection for ESD recovery
• 64-pin LQFP package
• Applications:
− Stand-alone USB hub
− PC motherboard USB hub, Ducking of notebook
− Any compound device to support USB HUB function