PCT
`
`wo~D INTELLECTUAL PROPERTY ORGANIZATION
`International Bureau
`
`@
`
`INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`
`(51) International Patent Classification 6 :
`G06F 13/10
`
`A1
`
`(11) International Publication Number:
`
`WO 99/01820
`
`(43) International Publication Date:
`
`14 January 1999 (14.01.99)
`
`(21) International Application Number:
`
`PCT/US98/13397
`
`(22) International Filing Date:
`
`26 June 1998 (26.06.98)
`
`(30) Priority Data:
`08/886,923
`
`2 July 1997 (02.07.97)
`
`US
`
`(71) Applicant: ANCHOR CHIPS INCORPORATED [US/US];
`Suite 212, 12396 World Trade Drive, San Diego, CA 92128
`(us).
`
`(81) Designated States: AL, AM, AT, AU, AZ, BA, BB, BG, BR,
`BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, GE,
`OH, HU, ILL, IS, JP, KE, KG, KP, K_R, KZ, LC, LK, LR,
`LS, LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, NZ,
`PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR,
`Tr, UA, UG, UZ, VN, YU, ZW, ARIPO patent (GH, GM,
`KE, LS, M’W, SD, SZ, UG, ZW), Eurasian patent (AM, AZ,
`BY, KG, KZ, MD, RU, TJ, TM), European patent (AT, BE,
`CH, CY, DE, DK, ES, FI, FR, GB, GR, lE, IT, LU, MC,
`NL, PT, SE), OAPI patent (BF, B J, CF, CG, CI, CM, GA,
`GN, ML, MR, NE, SN, TD, TG).
`
`(72) Inventors: SARTORE, Ronald, H.; 11511 Eastridge Place, San
`Diego, CA 92131 (US). LARKY, Steven, P.; 314 Del Mar
`Heights Road, Del Mar, CA 92014 (US).
`
`Published
`With international search report.
`With amended claims.
`
`(74) Agent: LOHSE, Timothy, W.; Gray Cary Ware & Freiedertrich,
`400 Hamilton Avenue, Palo Alto, CA 94301 (US).
`
`(54) Title: BUS INTERFACE SYSTEM AND METHOD
`
`(57) Abstract
`
`A system and method for recon-
`figuring a peripheral device (54) con-
`nected by a computer bus (60) and
`port to a host (52) from a first generic
`configuration to a second manufacturer
`specific configuration is provided in
`which the configuration of a periph-
`eral device may be electronically re-
`set. A peripheral interface device (76)
`for a standardized computer peripheral
`device bus and port is also provided
`in which a physical disconnection and
`recormection of the peripheral device
`is emulated to reconfigure the bus and
`port for a particular peripheral device.
`
`i i
`
`Host Computer
`
`&~ Operating 8ystem
`
`\
`Memory \
`\
`
`USB Interface
`
`I
`
`I
`/
`/
`USB Interface /
`/
`
`~q -..---
`
`CPU
`
`Loadable
`Memory
`
`Device
`
`EXHIBIT 1009
`IPR Petition for U.S. Patent No. 6,249,825
`
`Page 1
`
`

`

`Codes used to identify States party to the PCT on the front pages of pamphlets publishing international applications under the PCT.
`
`FOR THE PURPOSES OF INFORMATION ONLY
`
`AL
`AM
`AT
`AU
`AZ
`BA
`BB
`BE
`BF
`BG
`BJ
`BR
`BY
`CA
`CF
`CG
`CH
`CI
`CM
`CN
`CU
`CZ
`DE
`DK
`EE
`
`Albania
`Armenia
`Austria
`Australia
`Azerbaijan
`Bosnia and Herzegovina
`Barbados
`Belgium
`Burkina Faso
`Bulgaria
`Benin
`Brazil
`Belarus
`Canada
`Central African Republic
`Congo
`Switzerland
`Cfte d’Ivoire
`Cameroon
`China
`Cuba
`Czech Republic
`Germany
`Denmark
`Estonia
`
`ES
`FI
`FR
`GA
`GB
`GE
`GH
`GN
`GR
`HU
`IE
`IL
`IS
`IT
`JP
`KE
`KG
`KP
`
`KR
`KZ
`LC
`LI
`LK
`LR
`
`Spain
`Finland
`France
`Gabon
`United Kingdom
`Georgia
`Ghana
`Guinea
`Greece
`Hungary
`Ireland
`Israel
`Iceland
`Italy
`Japan
`Kenya
`Kyrgyzstan
`Democratic People’s
`Republic of Korea
`Republic of Korea
`Kazakstan
`Saint Lucia
`Liechtenstein
`Sri Lanka
`Liberia
`
`LS
`LT
`LU
`LV
`MC
`MD
`MG
`MK
`
`ML
`MN
`MR
`MW
`MX
`NE
`NL
`NO
`NZ
`PL
`PT
`RO
`RU
`SD
`SE
`SG
`
`Lesotho
`Lithuania
`Luxembourg
`Latvia
`Monaco
`Republic of Moldova
`Madagascar
`The former Yugoslav
`Republic of Macedonia
`Mali
`Mongolia
`Mauritania
`Malawi
`Mexico
`Niger
`Netherlands
`Norway
`New Zealand
`Poland
`Portugal
`Romania
`Russian Federation
`Sudan
`Sweden
`Singapore
`
`SI
`SK
`SN
`SZ
`TD
`TG
`"rJ
`TM
`TR
`TT
`UA
`UG
`US
`UZ
`VN
`YU
`ZW
`
`Slovenia
`Slovakia
`Senegal
`Swaziland
`Chad
`Togo
`Tajikistan
`Turkmenistan
`Turkey
`Trinidad and Tobago
`Ukraine
`Uganda
`United States of America
`Uzbekistan
`Viet Nam
`Yugoslavia
`Zimbabwe
`
`Page 2
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`
`BUS INTERFACE SYSTEM AND METHOD
`
`Background of the Invention
`
`This invention relates generally to a system and method for connecting a
`
`computer system to a computer bus and in particular to a system and method for
`
`interfacing a computer system to a standard universal serial peripheral device bus.
`
`In a typical computer system, a computer having a microprocessor may be
`
`connected to a plurality of peripheral devices, such as a printer or a modem, by one or
`
`more electrical buses and several different communications ports. Different peripheral
`
`devices have interfaces with different form factors and electrical characteristics, and
`
`these communications ports are used for a variety of different peripheral devices. A
`
`typical desktop computer may have a modem, a printer, a keyboard and a mouse
`
`connected to it. The modem may be connected to a serial port, the printer may be
`
`connected to a parallel port, the keyboard may be connected to a dedicated keyboard
`
`port and the mouse may be connected to a dedicated mouse port. Each of these
`
`communication ports may have different electrical characteristics, require different
`
`connectors and each has a different cable that runs from the peripheral device to the
`
`connector which connects to the computer communications port. For example, the
`
`serial port, the parallel port, the keyboard port and the mouse port all have different
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`characteristics, cables and different connectors. The result is a large number of
`
`diverse interfaces and cables that must be used. In addition, the electrical design of
`
`these communications ports typically requires that the computer be turned off before
`
`connecting and/or disconnecting a peripheral device from the port because the port
`
`may be permanently damaged otherwise. This prompted the design of a single
`
`standardized peripheral interface connection system which reduces the need for
`
`multiple connectors and cables, and permits the connection and disconnection of a
`
`peripheral device while the computer is turned on.
`
`A new emerging technology called the Universal Serial Bus (USB) is a system
`
`intended to create a single standardized peripheral device connection system. The
`
`USB makes the task of connecting peripheral devices to computers easier and more
`
`reliable since it uses a standardized connector and form factor, and makes operating
`
`those peripheral devices with the computer, easier and more reliable than with the
`
`various different types of communication ports. The computer to which these
`
`peripheral devices are connected by the USB is known as the "host computer". The
`
`USB replaces the multiple cable and connector types with a single standardized
`
`connection system. The USB also permits the connection and disconnection of USB
`
`compatible peripheral devices while the computer is turned on which eliminates the
`
`typical turning off and rebooting of the computer in order to connect or disconnect a
`
`peripheral device to the computer.
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`When a peripheral device is first connected to the USB and the host computer
`
`through a standard USB communications port, the presence of the connected peripheral
`
`device is detected and a configuration process of the USB for the connected peripheral
`
`device, known as device enumeration, begins. The enumeration process assigns a
`
`unique USB address to the connected peripheral device, queries the connected
`
`peripheral device about its requirements and capabilities, writes data about the
`
`connected peripheral device into the host computer’s operating system, and loads the
`
`appropriate software device driver from a storage location into the host computer’s
`
`operating system. During the query, a data table stored in the peripheral device, which
`
`contains the particular peripheral device’s configuration information, is read from the
`
`peripheral device into the host computer’s memory. Upon completion of the
`
`enumeration process, the connected peripheral device is recognized by the host
`
`computer’s operating system and may be used by application software being executed
`
`by the microprocessor of the host computer. The association of the device with the
`
`software device driver cannot be subsequently changed.
`
`In a serial bus system, such as the USB, the only opportunity for associating
`
`software device drivers with a peripheral device is at the time when the peripheral
`
`device is plugged into the USB and the enumeration process occurs. Thus, to alter the
`
`configuration or personality of a peripheral device, such as downloading new code or
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`configuration information into the memory of the peripheral device, the host computer
`
`system must detect a peripheral device connection or a disconnection and then a
`
`reconnection.
`
`The USB provides a number of advantages, as described above, over standard
`
`peripheral device connection techniques. The USB, however, does not provide a
`
`system and method for easily altering the configuration data for a peripheral device. In
`
`addition, the USB also does not provide a method for easily changing the software
`
`device driver associated with a particular peripheral device.
`
`Thus, there is a need for a system and method for interfacing to a universal
`
`serial bus which avoids these and other problems of known systems and methods, and
`
`it is to this end that the present invention is directed.
`
`Summary of the Invention
`
`The invention provides a universal serial bus interface system and method in
`
`which the configuration information for a plurality of different peripheral devices may
`
`be stored in the host computer rather than in the peripheral devices themselves. The
`
`flexibility of the universal serial bus is thereby increased because each peripheral
`
`device does not need to store configuration information. In addition, the configuration
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`information for any peripheral device may be easily modified to accommodate changes
`
`in the peripheral devices or to take advantage of other peripheral device features
`
`because it is located in the file system of the host computers. The configuration
`
`information may include configuration data, microprocessor code to be executed on the
`
`CPU in the peripheral device, and logic configuration data. The configuration
`
`information may be downloaded from the host computer into the peripheral device.
`
`In addition, the universal serial bus interface system and method permits the
`
`configuration information associated with the peripheral device to be electronically
`
`altered to match changes in the peripheral devices. Instead of physically
`
`disconnecting and reconnecting a peripheral device to reconfigure it, a peripheral
`
`device may be electronically disconnected and then reconnected to the USB (e.g. the
`
`disconnect/connect cycle may be electrically simulated) so that a change in the
`
`configuration information for a particular peripheral device may be implemented. One
`
`of many advantages of the electrical simulation of the disconnect and reconnect cycle
`
`is that since the peripheral device is physically connected to the bus during the
`
`electrical simulation, the peripheral device may utilize the electrical power supplied by
`
`the bus to operate the peripheral device. If the peripheral device is physically
`
`disconnected as in a conventional USB system, the peripheral device would require its
`
`own electrical power source. Thus, the computer system may, without human
`
`assistance, reconfigure a peripheral device connected to the USB.
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`In addition, the universal serial bus interface system and method may be a
`
`single semiconductor chip which may be incorporated into a plurality of peripheral
`
`devices made by a plurality of manufacturers. The chip may initially have a generic
`
`configuration (e.g., not specific to a particular peripheral device). Then, the
`
`appropriate configuration information for a particular peripheral device and
`
`manufacturer may be downloaded to the chip, an electronic simulation of the
`
`disconnection and reconnection of the peripheral device occurs, the peripheral device is
`
`recognized as a new, manufacturer specific peripheral device and the appropriate
`
`software device driver is loaded into the memory of the host computer.
`
`In accordance with the invention, a system and method for reconfiguring a
`
`peripheral device connected by a computer bus and port to a host computer is provided
`
`in which a host computer detects a peripheral device connected to the port in which the
`
`peripheral device has a first configuration. A second set of configuration information
`
`may be downloaded from the host computer into the peripheral device over the
`
`computer bus, and the configuration of the peripheral device is electronically reset
`
`from said first configuration to a second configuration based on the second set of
`
`configuration information.
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`In accordance with another aspect of the invention, a peripheral interface device
`
`for a standardized computer peripheral device bus and port is provided in which a
`
`peripheral device is physically connected to a computer system through a computer
`
`peripheral bus and port and the peripheral device has a first configuration. A second
`
`set of configuration information may be received from a computer system, and a
`
`physical disconnection and reconnection of the peripheral device is simulated to
`
`reconfigure the peripheral device to a second configuration based on the second
`
`configuration information.
`
`Brief Description of the Drawings
`
`Figure 1 is a diagram illustrating a conventional universal serial bus system in a
`
`computer system;
`
`Figure 2 is a diagram illustrating a universal serial bus system in accordance
`
`with the invention;
`
`Figure 3 is a diagram illustrating a conventional universal serial bus interface
`
`circuit;
`
`Figure 4 is a diagram illustrating a universal serial bus interface circuit in
`
`accordance with the invention;
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`Figure 5 is a diagram illustrating a peripheral device with a first configuration
`
`being connected to a computer system through a USB port and configured in
`
`accordance with the invention;
`
`Figure 6 is a diagram illustrating a peripheral device being configured with a
`
`second configuration in accordance with the invention;
`
`Figure 7 is a diagram illustrating a peripheral device being reconfigured with a
`
`third configuration in accordance with the invention; and
`
`Figure 8 is a flowchart illustrating a method for changing the configuration
`
`information for a peripheral device connected to a universal serial bus in accordance
`
`with the invention.
`
`Detailed Description of a Preferred Embodiment
`
`The invention is particularly applicable to a universal serial bus interface
`
`system and method. It is in this context that the invention will be described. It will be
`
`appreciated, however, that the system and method in accordance with the invention has
`
`greater utility, such as with other different computer buses and standardized interfaces.
`
`Figure 1 is a diagram illustrating a standardized bus interface, such as a
`
`conventional computer system 20, that may include a host computer system 22 and a
`
`peripheral device 24. The peripheral device is connected to the host computer by a
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`universal serial bus (USB) 26. The host computer may include a central processing
`
`unit (CPU) 28 connected to a USB interface (I/F) circuit 30, and the USB standard
`
`provides a universal electrical and physical interface for the peripheral devices via bus
`
`26. The CPU executes software application code located in a memory 31 and
`
`communicates data to and from the peripheral device through the USB interface and
`
`the USB 26. The host computer may also include an operating system 32 which may
`
`include a software device driver 33. The peripheral device 24 may include a USB
`
`interface circuit 34, a CPU 36 and a non-volatile memory 38 that may store
`
`configuration information describing the characteristics of the peripheral device. The
`
`non-volatile memory may be a read only memory (ROM) or an erasable programmable
`
`read only memory (EPROM).
`
`When the peripheral device is initially connected to the USB, an enumeration
`
`process is conducted in which the host computer determines the characteristics of the
`
`peripheral device by receiving the configuration information from the memory 38
`
`within the peripheral device, and configures the USB according to the characteristics of
`
`the peripheral device. As shown, the configuration information about the
`
`characteristics of the peripheral device in a conventional USB system is stored in a
`
`non-volatile memory 38 on the peripheral device. The data about the characteristics of
`
`the peripheral device is programmed into the non-volatile memory at the factory, and
`
`the characteristics of the peripheral device may not be easily altered. In addition, the
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`memory in the peripheral device stores all of the configuration information about the
`
`peripheral device which may require a large amount of memory in the peripheral
`
`device.
`
`Once the enumeration process has been completed, the CPU of the host
`
`computer may load an appropriate software device driver 33 for the peripheral device
`
`and the software applications being executed by that CPU of the host computer may
`
`communicate with the peripheral device using the USB. When the first peripheral
`
`device is disconnected and another peripheral device is connected to the USB, the
`
`enumeration process for the new peripheral device may be conducted and another
`
`software device driver may be loaded. The configuration of the peripheral device
`
`cannot be easily altered. Now, a universal serial bus system and method in accordance
`
`with the invention will be described.
`
`Figure 2 is a diagram illustrating a computer system 50 that may have a
`
`universal serial bus system in accordance with the invention. The computer system
`
`may include a host computer 52 connected to a peripheral device 54 by a universal
`
`serial bus (USB) 60. The host computer may include a CPU 62, a memory 64, an
`
`operating system 65 and a USB interface circuit 66. One or more peripheral device
`
`drivers, such as a first peripheral device driver 68, may be stored in the operating
`
`system 65. Each device driver contains information about the proper configuration of
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`the USB for a particular class of peripheral devices. The operating system within the
`
`host computer may also contain a plurality of different configuration information sets
`
`70, which may include configuration data for a particular peripheral device (including
`
`which device driver to use), microprocessor code to be executed by a CPU located in
`
`the peripheral device, or logic configuration data to configure logic circuits in the
`
`peripheral device. This invention advantageously enables these configuration
`
`information sets to be updated or altered easily since they are located in the host
`
`computer and not in a non-volatile memory in the peripheral device.
`
`The peripheral device 54 may include a USB interface system 71 and a CPU
`
`72. The USB interface system may include an alterable memory 74 such as a random
`
`access memory (RAM) or a flash electrically erasable programmable read only
`
`memory (flash EPROM), and a USB interface circuit 76. The memory 74 may initially
`
`contain an identification code to indicate which configuration information set should
`
`be downloaded to the peripheral device. The USB interface system 71 may be a
`
`semiconductor chip containing the USB interface circuit as well as the memory that
`
`may be added onto the peripheral device. The USB interface circuit in accordance
`
`with the invention is designed to meet USB standard specifications, such as
`
`communications protocols, electrical specifications and the USB form factor, and may
`
`permit the peripheral device to be disconnected and connected to the USB without the
`
`physical disconnection or connection of the peripheral device, as described below.
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`The various configuration information sets are stored in the host computer so
`
`that they may be easily updated or altered and then, using the electronic disconnect and
`
`reconnect method in accordance with the invention, the peripheral devices attached to
`
`the host computer may be dynamically reconfigured using the updated configuration
`
`information sets without the necessity to physically disconnect and reconnect the
`
`peripheral devices.
`
`In operation, during the initial factory configuration of the peripheral device
`
`with the USB interface system in accordance with the invention, the memory may store
`
`an identification code indicating the appropriate configuration information set to be
`
`loaded. Thus, when the peripheral device is first connected to the USB, the
`
`configuration information 70, including any microprocessor code applicable to the
`
`peripheral device and the appropriate configuration data for the peripheral device may
`
`be downloaded over the USB into the memory 74 of the peripheral device 54 as shown
`
`by the dashed arrow 78. The electrical simulation of the disconnection and
`
`reconnection of the peripheral device from the USB, as described below, may be
`
`initiated and a re-enumeration process may occur. During the re-enumeration process,
`
`the newly downloaded configuration information may be used to reconfigure the USB
`
`for the peripheral device and the host computer may select the appropriate software
`
`device driver 68 for the peripheral device based on the configuration information and
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`load the device driver into memory 64 as shown by arrow 80. For example, a
`
`plurality of different peripheral devices manufactured by different companies may each
`
`include a USB interface system in accordance with the invention. The USB interface
`
`system for each peripheral device is identical (e.g. has a USB interface circuit and a
`
`memory) except that each memory may contain an identification code that is unique to,
`
`for example, a particular manufacturer. When one of the peripheral devices is
`
`connected to the USB and the host computer, the appropriate configuration information
`
`for the peripheral device, based on the identification code, is downloaded over the USB
`
`to the memory of the peripheral device and the appropriate software device driver is
`
`loaded into the memory of the host computer. Thus, a plurality of different peripheral
`
`device may include the same USB interface system hardware since the configuration
`
`information is located in the operating system of the host computer. Now, a
`
`conventional USB interface circuit and the universal serial bus interface circuit in
`
`accordance with the invention that permits the electronic disconnection and
`
`reconnection of the peripheral device will be described.
`
`Figure 3 is a diagram illustrating a conventional host computer universal serial
`
`bus interface circuit 100 and a peripheral device USB interface circuit 101. The host
`
`computer USB interface 100 may include two USB data leads 102, 103 that may be
`
`labeled D+ and D-, which are both connected to ground through a resistor 112, 113
`
`respectively. The peripheral device USB interface 101 may include a buffer amplifier
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`104, having a first normal output of the buffer (D+) 106 and a second inverted output
`
`of the buffer (D-) 108. The D+ output of the buffer may be connected to a supply
`
`voltage, which may be 3.3 volts for example, through a 1.5 k~ resistor 110. In
`
`operation, the host computer detects the connection of a peripheral device by
`
`monitoring the voltage levels of one of the two USB data leads. In particular, in the
`
`computer host, the D+ data line is terminated with a 15 k~ resistor 112 to ground.
`
`Thus, when the D+ line is not connected to a peripheral device, the measured voltage
`
`of the D+ line is approximately zero volts and the host computer determines that no
`
`peripheral device is connected to the USB port. When a peripheral device is connected
`
`to the USB port, the 1.5k~ resistor 110 connected to a supply voltage of the peripheral
`
`device USB interface 101 adds a voltage to the D+ line and the D+ line at the host
`
`computer is pulled to above 3 volts which is detected as a connected peripheral device
`
`by the host computer and the host computer begins the enumeration process. Now, the
`
`USB interface circuit in accordance with the invention will be described.
`
`Figure 4 is a diagram illustrating a USB interface circuit for a peripheral device
`
`in accordance with the invention which permits the peripheral device to be
`
`electronically disconnected and/or reconnected to the USB without physically
`
`disconnecting and reconnecting the peripheral device from the USB (e.g., the electric
`
`simulation of a disconnect/connect cycle). As with the conventional USB interface,
`
`the host computer USB interface circuit 100 may include two USB data leads 102, 103
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`which may be labeled as D+ and D- as shown. As above, each data lead is connected
`
`to ground through a resistor and a 15 k~ resistor 112 connects the D+ data lead to
`
`ground. A peripheral device USB interface circuit 120 in accordance with the
`
`invention will now be described.
`
`The peripheral USB interface circuit 120 may include a buffer amplifier 122, a
`
`first buffer output 124 labeled D+ and a second buffer output 126 labeled D-. In
`
`accordance with the invention, the D+ data lead may be connected to a supply voltage,
`
`which may be 3.3 volts, through a 1.5 kff~ resistor 128 and an electrical switch 130, that
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`may be a semiconductor switch such as a field effect transistor (FET). The electrical
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`switch may have a control lead 132 which may control the operation of the electrical
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`switch. The electrical switch is normally controlled by the peripheral device, but the
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`host computer may download configuration information containing a command
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`instructing the peripheral device to actuate the electrical switch. Thus, both the
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`peripheral device itself and the host computer may control the electrical switch. As
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`above, when no peripheral device is physically connected to the USB, the host
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`computer reads zero volts on the D+ data lead.
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`When a peripheral device is connected to the USB, the electrical switch permits
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`the peripheral device to disconnect and then reconnect itself to the USB without the
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`physical disconnection of the peripheral device from the USB. In particular, if the
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`peripheral device is physically connected to the USB, but the electrical switch is open,
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`the D+ data lead is no longer connected to the supply voltage and the host computer
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`determines that the peripheral device has been disconnected even though the peripheral
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`device is still physically connected to the USB. Similarly, when the electrical switch is
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`closed again, the D+ data lead is again connected to the supply voltage and the host
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`computer will detect that the peripheral device has been reconnected to the USB.
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`Therefore, the physical disconnection and/or connection of the peripheral device may
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`be effected without actually physically disconnection and!or connecting the peripheral
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`device. This electronic disconnection and reconnection of the peripheral device, as
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`described above, in combination with the storage of the configuration information sets
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`on the host computer permits the configuration of the peripheral devices to be changed
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`easily without requiring the physical disconnection and reconnection of a peripheral
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`device. Now, an example of a system for connecting a plurality of different peripheral
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`devices each containing a USB interface system in accordance with the invention, to a
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`computer system will be described.
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`Figures 5, 6, and 7 are diagrams illustrating three different peripheral devices
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`from different manufacturers, for example, being connected to a host computer in
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`accordance with the invention. In each Figure, a computer system 140 may include a
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`host computer 142, a plurality of peripheral devices, such as peripheral device "A" 144
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`(shown in Figure 5), peripheral device "B" 146 (shown in Figure 6), peripheral device
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`"C" 148 (shown in Figure 7) and a USB bus 149. The host computer 142 may include
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`a CPU 150, a memory 152, an operating system 154 and a USB interface circuit 156.
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`The operating system, in this example, may include a plurality of software device
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`drivers, such as device driver "A" 158, device driver "B" 160 and device driver "C"
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`162, and a plurality of configuration information sets, such as device "A"
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`characteristics 164, device "B" characteristics 166 and device "C" characteristics 168.
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`Each peripheral device 144, 146, 148 may include a universal USB interface
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`system 170 that may include a USB interface circuit 172 as shown in Figure 4 and a
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`loadable memory 174. Each peripheral device may also include a CPU 176 and a non-
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`volatile memory 178. The non-volatile memory may store a unique manufacture
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`signature or identifier that identifies the appropriate configuration information to be
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`downloaded into the peripheral device. Now, the connection of each of these
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`peripheral device to the computer system will be described.
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`As shown in Figure 5, peripheral device "A" 144 may have a unique
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`manufacturer signature in the non-volatile memory 178. When the peripheral device is
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`connected to the computer system, the enumeration process begins in which the USB
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`interface system 170 is recognized by the USB as a generic device and the unique
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`manufacturer signature is read from the non-volatile memory by the CPU 150 over the
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`USB 149. The unique signature identifies device "A" characteristics 164 as the
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`appropriate configuration information and that configuration information may be
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`downloaded over the USB 149 into the memory 174 of the peripheral device as shown
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`by dashed arrow 180. Then the electrical simulation of the disconnection and
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`reconnection of the peripheral device occurs, as described above, which cause re-
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`enumeration of the peripheral device. During re-enumeration, device driver "A" 158,
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`which is identified by device "A" characteristics 164 as the appropriate device driver,
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`is loaded from the operating system into the memory, as shown by arrow 182, such
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`that the peripheral device is now recognized as a peripheral device with device "A"
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`characteristics. Thus, a generic hardware USB interface system may be incorporated
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`into a peripheral device and the particular characteristics for the particular peripheral
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`device may be later downloaded from the host computer into the peripheral device.
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`Similarly, as shown in Figures 6 and 7, the peripheral devices 146, 148 may
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`include the generic USB interface system and a unique manufacturer signature in the
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`non-volatile memory and may be re-enumerated in accordance with the invention so
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`that the appropriate device characteristics are downloaded from the host computer over
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`the USB into the memory of the peripheral device and the appropriate device driver
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`may be selected by the host computer. Thus, peripheral device "B" 146 (shown in
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`Figure 6) may have device "B" characteristics 166 downloaded into its memory, as
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`shown by dashed arrow 184 in Figure 6, and the host computer may use device driver
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`"B" 160, as shown by arrow 186 in Figure 6. The peripheral device "C" 148 (shown
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`in Figure 7) may have device "C" characteristics 168 downloaded into its memory as
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`shown by the dashed arrow 188 in Figure 7 and the host computer may use device
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`driver "C" 162 as shown by arrow 190 in Figure 7. Thus, a generic USB interface
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`system may be incorporated into a plurality of different peripheral devices, the
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`appropriate configuration information may be downloaded into the peripheral device,
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`and th