Computer graphics processing and selective visual display system – Display peripheral interface input device
Reexamination Certificate
1999-07-19
2002-12-24
Hjerpe, Richard (Department: 2674)
Computer graphics processing and selective visual display system
Display peripheral interface input device
C348S211130, C345S215000
Reexamination Certificate
active
06498598
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to apparatus and method for outputting a command from outside of a device to change a control method of the device to execute an operation different from that actuated by remote control executed by the device's control unit.
2. Description of the Related Art
Hitherto, peripheral devices of a personal computer (referred to as a PC hereinafter), such as a hard disk and a printer, have been connected to the PC through a universal interface for small computers, e.g., a digital interface (referred to as a digital I/F) such as a SCSI, for data communication.
Digital cameras and digital video cameras are also regarded as input means to a PC and are also peripheral devices. Recently, the technology of transferring images (such as still and motion pictures picked up by digital cameras and video cameras) into a PC along with accompanying voice signals, storing the pictures in a hard disk or editing them in the PC, and then color-printing the pictures using a printer has been developed and has gained popularity.
When such image data is outputted from the PC to the printer or to the hard disk, the data is communicated via the above-mentioned SCSI or the like. On that occasion, a versatile digital I/F having a high transfer data rate, such as the SCSI, is required for sending a large amount of data.
However, such conventional digital I/Fs are still inconvenient in many points because some of them have a low data transfer rate, or employ large-diameter cables for parallel communication, or have limitations in type and connecting scheme, or require I/F connectors in the same number as destinations to be connected.
Furthermore, in many of the general PCs and digital equipment for use at home, a connector for connection to a SCSI cable is provided on the back side of the PC. Such a connector has a relatively large size, and it is rather troublesome to couple the cable to the connector.
When connecting, to PCs, portable equipment (such as digital cameras and video cameras) must be connected to connectors on the PC back side at every use, which is very troublesome for users.
Digital data communication has been used for mutual communication between a PC and such peripheral devices, and has utilized conventional communication techniques. It is however expected in the future that the types of devices using digital data will increase, and an improvement of I/Fs can improve network communication among many interconnected digital devices including PC peripheral devices to include digital video cameras, digital storage medium playback apparatuses, etc. If so, such network communication will be very convenient for users. On the other hand, since such communication will often transfer an extremely large amount of data, the use of conventional communication techniques will make the network crowded and adversely affect the communication between other devices in the network.
In view of the above, a method has been proposed to overcome the problems encountered in the conventional digital I/Fs, and to employ a universal digital I/F (e.g., IEEE 1394-1995 High Performance Serial Bus) equipped on each piece of digital equipment in conformity with a unified standard for communication between all the types of digital equipment including PCs and peripheral devices thereof. Thus, the proposed method intends to realize data communication among devices when a PC, a printer and other peripheral devices, a digital camera, a digital VTR, a camcoder, etc. are connected to each other in the form of a network.
The IEEE 1394 I/F has several remarkable advantages. Because of high-speed serial communication, though described later in detail, a cable is relatively thin and highly flexible, and the connector size is much smaller than the case of using a SCSI cable. Further, a large amount of data such as image information can be transferred at a high speed along with device control data. In other words, communication using the IEEE 1394 I/F is greatly advantageous in that when connecting portable equipment (such as digital cameras and video cameras), the connection work is much less troublesome for users, and image information can be more easily transferred to PCs.
The IEEE 1394 serial bus will be described below in more detail.
(Technical Outline of IEEE 1394)
With the advent of home digital VTRs and DVD players, it has been required to support data transfers of large amounts of information (such as video data and audio data) in real time. In order to transfer such data in real time, and to input such data into a PC or transfer them to another piece of digital equipment, an interface is needed which has a required transfer function and is able to transfer data at a high speed. The IEEE 1394-1995 (High Performance Serial Bus) (referred to as the 1394 serial bus hereinafter) is an interface that has been developed from the above point of view.
FIG. 7
shows an example of a network system made up by using 1394 serial buses. The network system includes devices A, B, C, D, E, F, G and H. Twisted pair cables constituting 1394 serial buses are employed to interconnect between A and B, between A and C, between B and D, between D and E, between C and F, between C and G, between C and H. The devices A to H comprise, e.g., a PC, a digital VTR, a DVD player, a digital camera, a hard disk, a monitor, etc.
The devices can be interconnected in a mixed fashion of a daisy chain system and a node branch system with a high degree of flexibility.
Also, each device has its own specific ID, and recognizes the IDs of the other devices which constitute a network devices interconnected by the 1394 serial buses. Thus, just by connecting two pieces of digital equipment successively with one 1394 serial bus, one network is constructed by devices each of which has a relay function. The entire network has the feature of the 1394 serial buses, i.e., a function of automatically recognizing network devices, their connection status, etc. based on the plug and play function at the time when the bus cables are connected to the devices.
Further, when some device is removed from or newly added to the network as shown in
FIG. 7
, the bus reset is automatically made to reset the network configuration, and a new network is formed. This function makes it possible to always set and recognize the network configuration from time to time.
The 1394 serial buses allow data transfer rates of 100/200/400 Mbps. Devices having higher data transfer rates support the lower data transfer rates for compatibility between the devices.
As data transfer modes, there are an asynchronous transfer mode for transferring asynchronous data (referred to as Asynch data hereinafter) such as a control signal, and an isochronous transfer mode for transferring isochronous data (referred to as Iso data hereinafter) such as real-time video data and audio data. The Asynch data and the Iso data are transmitted in a mixed fashion within each cycle (being usually 125 &mgr;s) with a higher priority given to the Iso data, following transfer of a cycle start packet (CSP) which indicates the start of the cycle.
FIG. 8
shows constituent elements of the 1394 serial bus.
The 1394 serial bus is of a layered structure in its entirety. As shown in
FIG. 8
, the core of hardware components is a 1394 serial bus cable. A connector of the cable is connected to a connector port, and a physical layer and a link layer exist as other hardware components at a level higher than the connector port.
Those two hardware components essentially constitute an interface chip. The physical layer executes coding, control related to the connector, etc, and the link layer executes packet transfer, control of cycle time, etc.
A transaction layer (as one of the firmware components) manages data to be subjected to transfer (transaction), and issues commands such as Read and Write. A serial bus management (as the other firmware component) manages connection status of the devices connected to the bus, IDs, and the network configuration.
The above-des
Canon Kabushiki Kaisha
Eisen Alexander
Fitzpatrick ,Cella, Harper & Scinto
Hjerpe Richard
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