WO2001037105A1 - Device bay system with surprise removal prevention for supporting and controlling usb and ieee 1394 peripheral devices - Google Patents

Abstract

A system for connecting a plurality of peripheral devices to a computer is disclosed. The system includes a computer, an enclosure or Device Bay condo for housing peripheral devices, and USB and IEEE 1394 serial buses connecting the computer to the peripheral device enclosure. The enclosure having a plurality of bays (74A-D) is preferably accessible from the front, and is connected to the computer through USB (98) and/or IEEE 1394 connections (96, 100). The enclosure may accommodate two or four USB or IEEE 1394 peripherals and are cascadable to support virtually unlimited expansion of peripheral devices. Each enclosure contains a number of walk-up ports for convenient front panel or rear panel connection of additional peripherals.

Description

DEVICE BAY SYSTEM WITH SURPRISE REMOVAL PREVENTION FOR SUPPORTING AND CONTROLLING SB AND IEEE 1394 PERIPHERAL DEVICES

Cross-Reference to Related Applications

This application claims the benefit of U.S. Provisional Application Serial No. 60/172,281, filed November 17, 1999.

Field of the Invention

The present invention relates to personal computer (PC) based computer systems, and more particularly to a system for easily connecting peripheral devices to a computer system using high speed serial data buses, a controller, and a specially designed enclosure. The system is especially useful for controlling devices of embedded applications, such as industrial devices, telecommunication devices, medical equipment devices, data acquisition devices, etc. It has been shown that a similar system is useful for expanding existing PC based systems by adding more conventional peripheral devices.

Background of the Invention

The development of high-speed serial buses has prompted the need for a specification to facilitate system expansion for custom peripheral devices. A constant in the evolution of the history of computers has been the demand for increasingly higher bandwidths for buses and interface technology. In the early days, when the IBM PC XT was the PC standard, the 8-bit ISA bus was the standard for peripheral interface. With the advent of the AT, the 8-bit ISA bus was found to be short on resources and short on speed, so the 16-bit ISA bus was born. This bus ran at the same clock frequency, but its data path was twice as wide. As the 16-bit ISA bus became too slow for the processing power of evolving computers, other standards began to appear such as the EISA and the VESA buses. However, these buses were short lived and never truly gained popularity in embedded applications. Shortly after the introduction of EISA and VESA, the PCI bus came along, offering more bandwidth and features. The PCI bus is a 32-bit data bus with a clock frequency more than four times faster than that of the ISA bus.

For several years, computers had been shipping with both PCI and ISA bus slots. These slots had given developers of industrial and telecommunication applications the opportunity to leverage the high volume commodity PC platform as the basis of their control system.

As a result of inherent problems with the PCI and ISA buses, the USB and IEEE 1394 buses were created. These new serial buses were intended to make peripheral designs easy to develop, inexpensive to manufacture, and simple to install and service. The USB is a medium bandwidth serial bus operating at up to 12Mb/sec. This hot-swappable, plug and play half duplex serial bus permits nearly unlimited expansion by allowing a single externally accessible port to support up to 127 peripheral devices. With USB, expanding the PC became as straightforward as plugging a cable into a running computer. Following insertion of a four wire cable into a USB port on the computer, the operating system enables the device and loads the drivers, so that the peripheral device becomes available for use almost instantly.

Complimentary to USB is a higher speed serial bus, IEEE 1394, commonly referred to as

1394. IEEE 1394 is a hot swappable, plug and play, full duplex serial bus. This serial bus allows for transfer speeds up to 400Mb/sec with future versions to provide speeds up to 3.2Gb/sec.

Although USB and IEEE 1394 are rich in technological advantages, a few implementation issues present difficulties for certain embedded applications. One is the issue of surprise removal of devices. Because USB and IEEE 1394 are hot swappable and plug and play by nature, a user may decide at any time to remove the cable that connects the device to the computer. This may happen at an inopportune time, for example, during a motion operation or during data acquisition. Such surprise removal could cause catastrophic failure in a control or instrumentation system, rendering the machine useless.

Another implementation problem with USB and IEEE 1394 in industrial applications concerns the power required for the peripheral devices. Though both USB and IEEE 1394 can provide power to devices, the use of this power is limited to low current devices using a single voltage rail. Most industrial applications require a relatively large amount of current at several voltage levels, and often this power must be clean. Most developers would therefore choose to design embedded power supplies or to provide power from an external power supply, increasing system cost and complexity.

A final implementation difficulty has to do with mechanical issues. Neither USB nor 1394 has an associated specified mechanical enclosure for devices. The problem this creates is that every device in the control system could conceivably be a different size and have a separate set of requirements for mounting the device in an enclosure or rack system. This can render service difficult, because the system may need significant disassembly to remove damaged components from the chassis. Upgrading also becomes more complicated, since changes in mechanical dimensions may necessitate housing and panel redesign.

In order to solve the aforementioned implementation problems and to open USB and IEEE 1394 to a wider array of devices, a new industry standard has recently emerged and is building some momentum in the embedded computer market. The Device Bay standard developed by Compaq, Intel, and Microsoft, enhances the USB and IEEE 1394 specifications. The Device Bay standard is a specification for an electrical and mechanical form factor for the USB and IEEE 1394 high-speed serial buses, and is designed to allow hot swappable, plug and play expansion for computer peripherals.

Device Bay incorporates a single connector that supports both USB and IEEE 1394 and provides additional power to accommodate more power hungry devices. By its nature, Device Bay is inherently portable in that any computer that has a USB port, a IEEE 1394 port, and a Device Bay compatible operating system is capable of using Device Bay technology. If the devices work on one system with a particular configuration, they will work on all platforms.

Under current applications of peripheral devices, current ISA or PCI designs would be ported to Device Bay modules. The modules would have an onboard, low cost microprocessor to communicate with the Device Bay controller and handle the communications for the USB or IEEE 1394 interface. The microprocessor would also be used to add local intelligence to the device. For example, the microprocessor could initialize a high speed A/D, perform a power up self-test, or handle background functions such as polling the A/D channels and signal conditioning for the input. The microprocessor can also compress, time stamp, and organize the data in a logical way sparing the PC from having to perform these functions.

Since Device Bay is plug and play, the unit can already be powered up when a module is inserted. The operating system and application will immediately recognize the device, load appropriate drivers, and run the application.

It is believed that high-speed serial interfaces will become the standard peripheral interface for computer based embedded systems for most original equipment manufacturers.

OEM embedded systems involved with industrial control, medical applications, instrumentation, telecommunications, and other applications typically contain one or more proprietary cards that perform OEM specific functions.

Due to low cost and ease of development, many OEMs in the past have designed these cards for the ISA bus. As the ISA bus disappears from commodity computers, OEMs will need to find a different bus for new designs as well as a bus to which they can port their existing designs The only choices for OEMs to use while allowing use of commodity PCs are PCI, USB, and IEEE 1394.

The present invention improves the Device Bay standard for application to computer based embedded systems for original equipment manufacturers

Summary of the Invention

The present invention is a system for easily adding and controlling peripheral devices to computers especially for embedded applications involving industrial control, medical equipment, instrumentation, telephony and other applications.

The system includes a computer, an enclosure or Device Bay condo for housing peripheral devices, and USB and IEEE 1394 serial buses connecting the computer to the peripheral device enclosure. The computer includes a processor, RAM, a video card, and some type of mass storage, such as a hard drive. The enclosure having a plurality of bays is preferably accessible from the front, and is connected to the computer through USB and/or IEEE 1394 connections.

The enclosures may accommodate two or four USB or IEEE 1394 compatible peripherals and are preferably cascadable to support virtually unlimited expansion of peripheral devices Each enclosure contains a number of so-called "walk-up ports" for convenient front panel connection of additional peripherals, such as printers, keyboards, mice and scanners. In the most preferred embodiment, the four bay enclosure is approximately 7 inches high by 8.44 inches wide by 12.5 inches long, and provides four USB walk-up ports and three IEEE 1394 walk-up ports. The enclosure can be rack-mounted, with two units fitting side by side in a 5U chassis, or cascaded to accommodate up to 127 USB devices and up to 63 IEEE 1394 devices.

The enclosures provide the required power to each Device Bay peripheral, eliminating the need for independent peripheral power supplies. The remote enclosures ensure data integrity by disallowing the removal of any peripheral without first closing all applicable files and applications associated with the peripheral.

The present invention is a way to expand and integrate computers by using both USB and EEE 1394 high-speed serial buses. Both standards permit hot-swapping and plug-and-play to permit the user to easily add or remove peripherals. The peripherals can be quickly added or removed from a computer system without opening an enclosure, or powering down and rebooting. The remote enclosures permit expansion of desktop, industrial, and embedded PCs. This is accomplished by connecting multiple remote enclosures together.

The present invention provides a mechanical and electrical form factor for USB and IEEE 1394 peripheral devices within the Device Bay standard. The present invention provides support of up to 127 USB devices, 63 IEEE 1394 devices, USB walk up ports, IEEE 1394 walk up ports, foil power management for peripheral modules inside and outside of the enclosure, power and communication LED indicators, and prevention of surprise removal of device modules. One aspect of the invention is the mechanical surprise removal prevention. Another aspect of the invention is the peripheral device module enclosures. The standalone enclosures may accommodate two or four USB or IEEE 1394 peripherals and are cascadable to support virtually unlimited expansion of peripheral devices. Each enclosure contains a number of walk-up ports for convenient front panel or rear panel connection of additional peripherals.

The enclosure supports up to four standard PC form factor devices. They can be plugged in or removed while the system is under power. The enclosure links to the host computer or other system via LEEE 1394 or USB serial buses. The USB provides a serial link with a current maximum throughput of 12Mb/sec and IEEE 1394 supports 100, 200 or 400 Mb/sec with current extensions moving those rates up to 800 and 1600 Mb/sec. These serial buses, especially IEEE 1394, can serve as a connection for connecting multiple enclosures. Thus, developers can string together multiple enclosures to create a unique PC based system for a variety of applications. Additionally, developers can add processing power and special functions available in modules to fit the standard peripheral form factors.

Both enclosure configurations include their own power supplies and can be linked via the

USB or IEEE 1394 serial buses. In a rack mount configuration, the enclosures can share one another's power supply, eliminating the need for a power supply in each enclosure.

Various other features, objects, and advantages of the invention will be made apparent to those skilled in the art from the following drawings and detailed description of the invention.

Brief Description of the Drawings

FIG. 1 is a functional block diagram of the system of the present invention;

FIG. 2 A is a front perspective view of a two-bay enclosure of the present invention; FIG. 2B is a rear perspective view of the two-bay enclosure of FIG. 2A;

FIG. 3 A is a front perspective view of a four-bay enclosure in accordance with another embodiment of the present invention;

FIG. 3B is a rear perspective view of the four-bay enclosure of FIG. 3A; FIG. 4 is a functional black diagram of the components of the four-bay enclosure shown in FIGS. 3A and 3B; and

FIG. 5 is a functional block diagram of the electronic circuitry on a Device Bay Controller printed circuit board.

Detailed Description of the Invention Referring first to FIG. 1 , which shows an overall general block diagram of one embodiment of the system of the present invention. The system 10 includes a host computer 12 for operating and controlling a plurality of peripheral devices 20 connected to the computer 12 over high-speed serial data buses 16, 18, such as a Universal Serial Bus (USB) 16 and an IEEE 1394 bus 18. The peripheral devices 20 are preferably installed in a uniquely designed peripheral device enclosure 14. The enclosure 14 is preferably a Device Bay compatible enclosure which meets the Device Bay standards and specification.

FIG. 2A illustrates a first embodiment of a Device Bay enclosure, which is preferably a two-bay peripheral device enclosure 14A. The enclosure 14A includes two bays 50A, 50B for receiving two peripheral devices 20 A, 20B. Underneath each of the two openings are a power supply status LED, an activity or a communication LED situated next to a remove request push button, and an ejector lever for ejecting the peripheral device installed in the open bay. FIG. 2B is a rear perspective view of the two-bay enclosure showing the power supply with AC input connector, two USB walk-up ports, two IEEE 1394 walk-up ports, a USB connection to the host computer, an IEEE 1394 connection to the host computer, and a power switch. Each of the enclosures include two open bays for inserting peripheral devices therein, a power supply, a uniquely designed Device Bay Controller printed circuit board mounted within the enclosure, a small solenoid activated peripheral device lock and unlock printed circuit board, and interface hardware for connecting the peripheral devices to the host computer and to other external devices.

FIG. 3 A illustrates another embodiment of a peripheral device enclosure. The enclosure is preferably a four-bay peripheral device enclosure 12B. The enclosure 12B includes four open bays 30A, 30B, 30C, 30D for receiving up to four peripheral devices (not shown). Underneath each of the openings is a power supply status LED, an activity or a communication LED situated next to a remove request push button, and an ejector lever for ejecting the peripheral device installed in the open bay. The enclosure further includes a keyed lock to prevent unauthorized removal of the peripheral devices from the enclosure during use. The front of the enclosure also includes two USB walk-up ports. At least one side of the enclosure is vented to provide cooling.

FIG. 3B is a rear perspective view of the four-bay enclosure showing the power supply with AC input connector, two USB walk-up ports, three IEEE 1394 walk-up ports, a USB connection to the host computer, an IEEE 1394 connection to the host computer, and a power switch. Each of the enclosures include four open bays for inserting peripheral devices therein, a power supply, a uniquely designed Device Bay Controller printed circuit board mounted within the enclosure, a peripheral device lock and unlock printed circuit board for each bay, and interface hardware for connecting the peripheral devices to the host computer and to other external devices.

FIG. 4 shows a functional black diagram of the components and electronics within the four-bay enclosure. The enclosure 14B includes electronic circuitry on at least one circuit board for controlling the system. The circuit boards preferably include a Device Bay Controller circuit board and a solenoid activated lock and unlock circuit board. The Device Bay Controller circuitry includes a controller and associated firmware 50, Fig. 4, for controlling operation of the system. The system shown in Fig. 3 includes four bays 34A, 34B, 34C, 34D controlled by a dual controller 36. The bays are essentially mechanical sockets that accept a peripheral device. These devices include such peripherals as CD ROMS, hard drives, floppies, telecommunication devices such as modems and POTS interfaces, servo and stepper controllers, communication devices, data acquisition for test and measurement devices, medical devices, etc. A connector located at the rear of each of the bays provides all electrical connections between the Device Bay controller 36, USB, IEEE 1394, and power to the peripheral device. A six-port PHY (physical layer interface) interface circuit 40 receives an input from the PC host computer 10, Fig. 1, and outputs a signal to up to five IEEE 1394 signal ports. A USB four port hub 42 is a circuit whose input is a USB port from the PC host computer 10, Fig. 1, and outputs three USB ports. Walk-up ports 44, 46 are discrete USB and IEEE 1394 ports which are available to the outside of the enclosure. These ports allow the connection of external peripherals to the enclosure. These devices can be any USB or 1394 compatible device. These ports also allow the addition of other enclosures for expansion.

FIG. 5 illustrates a functional block diagram of the system of the present invention with the Device Bay controller circuit board 50 as its main component. The circuitry on the Device Bay controller circuit board 50 together with an embedded software program and operating system coordinates and controls all of the functions of the bays 34A, 34B, 34C, 34D. These functions include power monitoring and control 52, peripheral device detection 54, peripheral device lock and unlock 56, USB and IEEE 1394 coordination 58, eject request control 60, mechanical key lock detection 62 four bay systems only), and power and activity status LEDs.

While the invention has been described with reference to preferred embodiments, those skilled in the art will appreciate that certain substitutions, alterations and omissions may be made without departing from the spirit of the invention. Accordingly, the foregoing description is meant to be exemplary only, and should not limit the scope of the invention.

Operation of the system as explained by adding and removing a peripheral device from the enclosure is as follows. To add a device, any USB or IEEE 1394 compatible device may be inserted into an open bay in the enclosure. As the device is inserted into a connector on a backplane at the rear of the enclosure, the Device Bay Controller circuitry and software recognize the peripheral device, initialize it and prepare it for operation. The device is mechanically and electrically locked in the enclosure. To remove a device, a user presses the remove request push button, a signal is sent to the host computer to remove the device, power is removed from the device, and the user pulls the eject lever. The current design supports non- Device Bay peripherals and various operating systems not supported by the Device Bay standard.

Claims

ClaimsI claim:

1. A system for connecting a plurality of peripheral devices to a computer, the system comprising: an enclosure having a frame and a plurality of open bays for accepting the plurahty of peripheral devices therein, a hardware interface to at least one bus which requires unique identifiers for each active device on the bus; a controller for controlling operation of the hardware interface; a locking means for locking and unlocking the peripheral devices in the enclosure; a power supply for supplying power to the control circuitry, hardware interface and open bays; and software embedded into the controller for recognizing and controlling operation of peripheral devices.

2. The system of claim 1 wherein the interface controller is a Device Bay Controller.

3. The system of claim 1 wherein the enclosure is coupled to a host computer.

4. The system of claim 1 wherein the hardware interface is an LEEE 1394 interface.

5. The apparatus of claim 1 wherein the hardware interface is a USB interface.

6. The system of claim 1 wherein the enclosure provides hardware interface walk-up ports for connecting external devices.

7. The system of claim 1 wherein the controller and embedded software provide power monitoring and control, peripheral device detection, peripheral device lock and unlock, USB and IEEE 1394 coordination, eject request control, mechanical key lock detection, and power and activity status indication.

8. A Device Bay compatible computer system comprising: a Device Bay enclosure and a Device Bay Controller which is electrically connected to connectors for externally removable device bay modules in the Device Bay enclosure; a USB hardware interface; an IEEE 1394 hardware interface; and embedded software coupled to an operating system in a host computer for controlling the system.

9. The system of claim 8 wherein the Device Bay Controller interfaces to a USB system bus through a USB hub controller

10. A computer system comprising: at least one device insertion location having a standard interface for components which may be inserted therein, the standard interface allowing the components to use any one of multiple different signal interface formats; and control electronics for controlling the components

11 The computer system of claim 10 wherein the control electronics includes an interface controller. 12 The computer system of claim 10 wherein the control electronics includes a first bus interface circuitry, which provides data communications between the interface controller and a first system serial bus

13 The computer system of claim 12 wherein the first bus interface circuitry is a USB

14 The computer system of claim 10 wherein the control electronics includes a second bus interface circuitry, which provides data communications between the interface controller and a second system serial bus

15 The computer system of claim 14 wherein the second bus interface circuitry is an IEEE 1394 bus

16 The computer system of claim 10 wherein the interface controller is connected directly to a USB

17 The computer system of claim 10 wherein the interface controller is connected directly to an IEEE 1394 bus

18 The computer system of claim 10 wherein the device insertion location is part of an enclosure

19 The computer system of claim 18 wherein the enclosure conforms to a Device Bay specification