1996-11-08 , E/IC-481/650

Eindhoven, The Netherlands - 8 November 1996 - Following the demonstration of the worldÌs first standalone USB Hub at WINHEC in April 1996, Philips Semiconductors' Logic Product group has now launched the PDIUSBH11 integrated circuit that contains all the functionality required of a standalone four way USB Hub. This is the first commercially available USB Hub IC with samples already available and volume production from November 1996.

The PDIUSBH11 provides one upstream USB port and four downstream USB ports. It also contains an embedded USB function with associated integrated memory which can be accessed by an external microcontroller using the industry standard I²C bus, enabling the monitor or keyboard to communicate with the host PC. This makes it ideal for use in monitors or keyboards where there is already a microcontroller or gives the designer the choice of using a microcontroller of their own choosing.

Between the upstream port and downstream ports is a "repeater" block that is responsible for broadcasting the USB packets from the upstream port to the peripheral device connected to the relevant downstream port. It also broadcasts messages from the downstream ports to the PC via the upstream port.

A digital Serial Interface Engine (SIE) is also included inside the IC. The SIE recovers the serial data and converts it into parallel format. The Memory Management Unit (MMU) then stores the data into the internal RAM.

Thus, when the PC sends data via the USB to the hub, it ends up in the internal memory of the PDIUSBH11 which then generates an interrupt on one of its pins to indicate to the system microcontroller that the data has arrived. The monitor or keyboard system microcontroller can then read this data from the memory via the I²C bus. Similarly, when the peripheral device wants to send data to the PC, it writes the data into the memory of the PDIUSBH11 using the I²C bus. The PDIUSBH11 then takes care of converting this data into USB protocol and transmitting it to the PC via the upstream port. The I²C bus interface on the PDIUSBH11 is a slave receiver device which means no special I²C bus hardware is required to be implemented in the system microcontroller of the peripheral device.

In the case of using PDIUSBH11 in a monitor application, the IC provides USB expandability within the PC system, functioning as a hub, as well as providing plug and play control of the monitor. The PC can automatically detect the presence of a monitor, read its display capabilities and automatically set the correct video mode suitable for the monitor.

It also allows the user to adjust the various geometric parameters (e.g. H and V size, east west correction, pin cushion, etc.) together with the normal user controls such as brightness and contrast. These adjustments are done from software running on the PC, not necessarily using the controls on the front panel of the monitor. The bi-directional nature of USB enables consistency to be maintained with manual controls.

A small amount of control software is required to drive the PDIUSBH11 device. This may reside in the existing monitor system microcontroller or can be implemented in a small, low cost dedicated microcontroller.

The PDIUSBH11 conforms to the USB specification version 1.0. Priced at around $6 in 10,000 volumes, it is available in a 32 pin SDIP package and operates from a 3.3V supply voltage. Samples are available now and volume production is scheduled for Q4 1996.

Philips Semiconductors, a division of Philips Electronics NV, headquartered in Eindhoven, The Netherlands, is the eleventh largest semiconductor supplier in the world. Philips Semiconductors' innovations in digital audio, video, and mobile technology position the company as a leader in the consumer, multimedia and wireless communications markets. Sales offices are located in all major markets around the world and are supported by regional systems labs.