National Semiconductor Introduces USB Hub Controller Optimized for PC Monitors; USB Host Controller Solution Available For Mobile PCS

Business Wire, Feb 10, 1997

SANTA CLARA, Calif.--(BUSINESS WIRE)--Feb. 10, 1997--National Semiconductor Corporation(R) today introduced the LM1050 USB Hub Controller, a Universal Serial Bus (USB) device that is the industry's most optimized host controller solution for PC monitors. National also highlighted the USB Host Controller capability of its previously announced PC87560 PCI SystemI/O Controller.

The LM1050 performs USB hub functions, provides CRT monitor control capabilities and integrates clock generation features for system-level timing, which eliminates the need for a separate microprocessor clock and reduces overall system costs. In addition, it has a dual-function microcontroller interface that allows monitor manufacturers to use one design for multiple models, thus reducing design complexity and time-to-market while further lowering system costs.

"The National Semiconductor hub controller is a key technology to simplify PC connectivity. Adding USB to the monitor adds simple expansion capability, and solves a long-standing problem of complexity when connecting to the various ports in the back of the PC," says Bill Veghte, Group Manager of the Windows Platform, Microsoft Corporation.

The USB standard allows non-technical PC users to add new external components and peripherals, such as mice, keyboards, printers and scanners, to their PC systems quickly and easily using a single thin cable and small connectors. In USB-based PCs, a "host controller" provides multiple USB ports, for connecting peripherals that function as "hubs" or "nodes". A hub has several USB ports to accommodate additional peripherals, while nodes have a single port that connects to either a host controller or a hub. In addition, hub and node functions can be combined.

LM1050 USB Hub Controller

The LM1050 hub controller is used with a microcontroller and firmware to perform two functions within a PC system's monitor.

First, it provides a full-featured, USB Specification Rev. 1.0-compliant hub site within any microprocessor-controlled CRT monitor. As a hub, the LM1050 has five ports: an "upstream" port that connects to a host controller in the PC, and four "downstream" hardware ports to which other USB peripherals can be connected. Additional downstream ports can be emulated in firmware to increase expansion capabilities. Transceivers for all the ports are integrated on-chip, eliminating the need for external components.

Second, the LM1050 emulates a downstream port to perform a node function for controlling the monitor. With this function, the PC user can change colors, adjust geometry, and otherwise control the set-up of the monitor using a windowing application on the PC. This user-friendly interface makes it more convenient to customize and adjust the monitor display to accommodate individual tastes and requirements.

Data flow to and from the ports for both hub and monitor functions is controlled by a microcontroller that is connected to a hardware-selectable I2C-compatible or UART interface. When configured as an I2C type, the interface operates at up to 400 kHz, and as a UART, it operates at a programmable rate of up to 750 kilobaud rate. This flexible interface allows a monitor manufacturer to use one design across multiple models, regardless of microcontroller choice. National's LM1050 is the only currently available USB hub with this capability.

Also unique to the National LM1050 are an on-chip 3.3V voltage regulator, an oscillator, and a clock generator. These mixed-signal functions allow a single inexpensive crystal to be used for all system timing functions, eliminating other oscillators and clock circuits and lowering overall system costs and design complexity.

To further ensure the lowest system cost, the LM1050 offers additional power and ground pins and an optimized pin-out that allows low-cost, single-sided printed circuit boards to be used.

According to Harry Inia, product marketing manager for National's Monitors Group, "Our first stand-alone USB device is intended for monitor applications for several reasons. First, since the monitor is always in front of the user, it's the natural and most accessible place for easily connecting peripherals. Second, the monitor is powered from the wall socket, so power can be readily supplied to high-power downstream peripherals."

Inia added, "National has more than 10 years of experience in the monitor market, so we know what the market needs and how to meet those requirements. We combined that experience with our mixed-signal capabilities in defining the LM1050, and will continue to leverage it into the area of application support."

Computer Access Technology Corporation (CATC) recently introduced its Galaxy USB Hub(TM) family, of which the first member, the NorthStar USB Hub, is based on the National LM1050. Dan Wilnai, president of CATC, said, "We're very excited about the capabilities of the National USB hub controller. It enables us to offer the low- cost NorthStar USB Hub product, which is an essential system element for connecting the multitude of USB and legacy devices to USB computers."