WO1998049807A1 - Dispositif de commande de bus et systeme de traitement de l'information - Google Patents

Dispositif de commande de bus et systeme de traitement de l'information Download PDF

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Publication number
WO1998049807A1
WO1998049807A1 PCT/JP1998/001876 JP9801876W WO9849807A1 WO 1998049807 A1 WO1998049807 A1 WO 1998049807A1 JP 9801876 W JP9801876 W JP 9801876W WO 9849807 A1 WO9849807 A1 WO 9849807A1
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WO
WIPO (PCT)
Prior art keywords
signal
node
bus
bucket
port
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PCT/JP1998/001876
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English (en)
Japanese (ja)
Inventor
Soichi Isono
Hitoshi Ogawa
Katsumi Yamamoto
Original Assignee
Hitachi, Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi, Ltd. filed Critical Hitachi, Ltd.
Publication of WO1998049807A1 publication Critical patent/WO1998049807A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/02—Details
    • H04L12/10—Current supply arrangements

Definitions

  • the present invention relates to a bus control device and an information processing system, and more particularly to a bus control device and an information processing system suitable for power saving in a system to which a serial bus is applied.
  • IEEE 1394 bus As a serial bus for information processing systems, the IEEE 1394 bus is a standard established by the United States Institute of Electronics and Electronics Engineers, Inc. (hereinafter referred to as IEEE). It is enacted as 95. Details of the IEEE1394 are disclosed in “IEEE Standard for a High Performance Serial Bus” issued by the IEEE.
  • FIG. 1 a description will be given of the cable connection specification of the IEEE 1394 bus c .
  • a plurality of devices are connected in a tree shape by cables. Each connected device is called a node.
  • each node a plurality of locations where cables are connected are provided.
  • the point where the cable is connected is called a port.
  • the cable connection may be branched.
  • Buckets are sent and received between the nodes via cables.
  • Command No. data is carried by sending and receiving this bucket.
  • each node is considered to be connected to one virtual bus that is connected through one or more other nodes. For this reason, a bucket received from a certain node is sent to all nodes.
  • a transmission path in which the entire connected transmission path acts as one virtual bus is called a virtual bus.
  • Figure 1 shows the packet transmission procedure performed by a conventional serial bus controller. A configuration example will be described.
  • node # 0 when sending a bucket from node # 0 to node # 1, first, node # 0 sends a bucket to node # 2. Then, node # 2 sends the packet received from node # 0 to node # 3 in addition to node #l. Thus, the bucket sent from node # 0 is transmitted to node # 1.
  • a bus collision means that multiple nodes transmit buckets at the same time and interfere with each other.
  • a node sending a packet waits until the bus is free.
  • the node monitors the signal of the cable connected to its own device, detects that no bucket is being sent, and determines that the bus is free. If the bus is free, it issues a bus use request signal, and if it gets the right to use the bus, it sends a bucket.
  • the virtual bus also sends buckets to nodes that do not actually use the data and commands contained in the bucket. For this reason, there is a problem that power for transmitting and receiving unused buckets is wasted.
  • a packet for transmitting another data is sent on a path where the bucket is not transmitted, depending on the use state of the bus. Bus collisions can occur when packets are transferred.
  • a first object of the present invention is to reduce power consumption by transferring a bucket to an unnecessary node in a virtual bus.
  • a second object of the present invention is to prevent a bus collision in a virtual bus in a state where power consumption due to transfer of a bucket to an unnecessary node is reduced.
  • a first storage unit for storing information indicating the partner node connected to each of the ports in association with each port
  • a search unit for searching the first storage unit for port information in which information indicating a destination node to which the signal is to be transmitted is stored in association with the first storage unit;
  • Devices to be connected have a plurality of transmission lines connected by one-to-one serial signals, and the plurality of transmission lines constitute a virtual serial bus transmission line as a whole.
  • a storage unit for storing a connection state in which the devices are connected
  • a discriminator for discriminating a path necessary for connecting a source and a destination of the signal and an unnecessary path
  • An extraction unit for extracting, from the ports indicated by the information stored in the first storage unit, ports that have not been searched by the search unit;
  • a suppression signal transmission unit for transmitting a suppression signal which is a suppression signal for suppressing signal transmission from another node and generated with lower power consumption than a normal signal, to the port extracted by the extraction unit. And is further provided by:
  • ADVANTAGE OF THE INVENTION According to this invention, about the port which is unnecessary for packet transmission, transmission of the packet from the port can be omitted. Therefore, the power consumption of the device provided with this port can be reduced. In addition, it is possible to suppress the transmission of buckets to nodes that are not necessary for bucket transmission. Therefore, it is possible to reduce power consumption in each connected device and in a system to which a plurality of devices are connected. Also, while the bucket is being transmitted to the required node, the transmission of the bucket from other nodes is suppressed, so that bus collision is prevented.
  • the bus connection form can be dynamically acquired while the virtual bus system is operating. For this reason, it is possible to easily cope with a change in the connection mode, for example, connection / disconnection or movement of a device.
  • FIG. 1 is a configuration diagram showing a system constructed by connecting a plurality of devices to a virtual serial bus.
  • FIG. 2 is a configuration diagram showing a system to which the second embodiment of the present invention is applied.
  • FIG. 3 is a block diagram showing the configuration of a node.
  • FIG. 4 is a block diagram showing a configuration of a personal computer.
  • FIG. 5 is a block diagram showing the configuration of the magnetic disk drive.
  • FIG. 6 is a block diagram showing the configuration of the serial bus control unit.
  • FIG. 7 is an explanatory diagram schematically showing connections between nodes.
  • FIG. 8 is an explanatory diagram showing the relationship between the definition of the received value and the received signal.
  • FIG. 9 is an explanatory diagram showing the relationship between the signal determination value and the logical values of the reception value and the transmission value.
  • FIG. 10 is an explanatory diagram showing a signal state name and a function to be assigned to each transmission value.
  • FIG. 11 is an explanatory diagram showing signal state names and assigned functions for each received value.
  • -Fig. 12 is an explanatory diagram schematically showing the bit transfer method.
  • FIG. 13A-13D is an explanatory view showing the structure of a self-ID bucket.
  • FIG. 14 is an explanatory diagram showing the configuration of the asynchronous bucket.
  • FIG. 15 is an explanatory diagram showing the configuration of an isochronous bucket.
  • FIG. 16 is an explanatory diagram showing the configuration of the ACK bucket.
  • FIG. 17 is an explanatory diagram showing the relationship between node numbers and port numbers.
  • FIG. 18 is an explanatory diagram showing the relationship between channel numbers and transfer destination port numbers.
  • FIG. 19 is a time chart showing the procedure of operation at the time of bus initialization.
  • FIG. 20 is a time chart showing the procedure of the transfer operation of the isochronous bucket.
  • FIG. 21 is a flowchart showing a procedure of processing in the bucket analysis unit.
  • FIG. 22 is a block diagram showing a configuration of a serial bus control device to which the first embodiment of the present invention is applied.
  • the serial bus control device 40 is configured to include a storage unit 45, an arithmetic control unit 46, and an interface unit 47.
  • the storage unit 45 information indicating each port in a device provided with the serial bus control device 40 is stored in a first storage area in advance, and the arithmetic control unit 46 executes processing. Therefore, a program describing the procedure is stored in advance. The arithmetic control unit 46 executes a process for controlling the serial bus.
  • the interface unit 47 connects the arithmetic processing unit 46 with the storage unit 45, and transmits and receives signals to and from the main function unit of the device provided with the serial bus control device 40. For transmitting and receiving signals to and from a port provided in the system.
  • the arithmetic processing unit 46 transmits information indicating that the nodes connected to the bus transmit a signal including information indicating each node, and acquire a node included in the signal when the bus is constructed. And the nodes connected to the ports are stored in the second storage area of the storage unit 45 in association with each port. Further, when transmitting a signal, a port in which a destination node to which the signal is to be transmitted is stored in association with a port stored in the second storage area of the storage unit 45. Search for. Then, the interface unit 47 is provided with information indicating a signal to be transmitted and an instruction to selectively transmit the signal indicated by the information to the searched port.
  • the arithmetic processing unit 46 extracts ports excluding the searched ports from among the ports indicated by the information stored in the second storage area.
  • the interface unit 47 is given information indicating a suppression signal for inhibiting transmission of a signal to the node and an instruction to transmit the suppression signal to the extracted node.
  • node # 2 is provided with a serial bus control device 40 to which the present invention is applied.
  • the node provided with the serial bus control device 40 may be another node, and the number provided is not limited to one.
  • the serial bus control device 40 may be provided for all nodes.
  • node # 2 when a bucket is sent from node # 0 to node # 1, first, a bucket is sent from node # 0 to node # 2. Then, node # 2 sends the bucket received from node # 0 only to node # 1. Also, it sends a suppression signal to node # 3, and suppresses the sending of buckets from node # 3.
  • the power consumption for transmitting the suppression signal can be made smaller than the power consumption for transmitting the bucket. This is because the suppression signal may have a lower frequency than the bucket signal. Particularly, by using a DC signal as the suppression signal, it is possible to reduce power consumption.
  • bus based on the IE EE 1394 specification is used as a virtual bus, but the bus to which the present invention is applied connects a plurality of devices with one-to-one serial signals. Any bus that uses the above connection collectively and enables data transfer equivalent to the virtual connection of each device to one bus may be used.
  • the bus may be based on specifications.
  • an information processing system 100 in the present embodiment includes a personal computer (hereinafter, referred to as a PC) 30 and a magnetic disk device (hereinafter, referred to as an HDD) 31 and 3.
  • a CD-ROM reader hereinafter referred to as CD-ROM
  • DVTR digital video tape recorder
  • DVD digital video disc reader
  • the display device 37 for example, a CRT display device, a liquid crystal display device, or the like can be used.
  • a television having an image input terminal can be used as the display device 37.
  • image information may be input to the RF input terminal of the television via an RF converter or the like to display an image.
  • the PC 30 has two IE 13 94 ports 16-1 and 16-2.
  • HDD 31, 32 and CD-ROM 33 are connected to one port 16-1 of IE EE 1394 port provided in the PC 30, and the first IE EE 1 It is composed of 3 94 buses.
  • the HDDs 31 and 32 and the CD-ROM 33 are used as ordinary external storage devices for the PC 30.
  • the other port 16 of the IE 1394 port provided in the PC 30 is used.
  • a DVTR 36, a digital camera 35, a DVD 34, and a display device 37 are connected to form a second IEEE 1394 bus different from the first IEEE 1394 bus. are doing. These are used for processing image information.
  • image information digitized by the digital camera 35 and the DVD 34 is acquired, the acquired image information is stored by the DVTR 36, and an image indicated by the image information is displayed by the display device 37. be able to.
  • the acquired image information can be directly displayed on the display device 37.
  • a digital video tape in which image information is stored in advance may be reproduced using the DVTR 36 to acquire the image information.
  • the data capacity is large, and the first IE EE 394 bus to which the HDDs 31 and 32 and the CD-ROM device are connected, in which data having a small data capacity and frequent reading and writing are stored, has a large data capacity. Reading and writing are continuously performed for a long time. Data is stored.
  • the DVD 34 and the DVTR 36 are connected to the second IEEE 1394 bus to be connected to operate independently. For this reason, it is possible to prevent the performance of the entire system from deteriorating when data having different read / write characteristics is transmitted by the same node.
  • Examples of data stored in the HDDs 31 and 32 and the CD-ROM device include, for example, programs.
  • each device is configured to include a main function unit 41 for realizing a function unique to each device, and a serial bus control unit 42 for controlling the IEEE1394 bus.
  • the PC 30 includes a main function unit 411 and two serial bus control units 42-1 and 42-2.
  • the main function unit 4 11 comprises a central processing unit (hereinafter referred to as a CPU) 51 for calculating data and the like, a memory 52 for storing data and programs, and a data processor. It has a display section 53 for displaying, an input section 54 for receiving instructions from the operator, and a normal parallel bus 55 for connecting these.
  • a CPU central processing unit
  • Each of the two serial bus controllers 42-1 and 42-2 can operate a single serial bus. Further, the serial bus control unit 42-1 and the serial bus control unit 42-2 can operate independently of each other. Accordingly, the PC 30 can operate the two serial buses independently of each other. C In particular, the serial bus control unit 42-2—to which the DVTR 36 shown in FIG. Provides a dedicated path 56 for sending image data directly to the display. As a result, even when a moving image having a large amount of data is reproduced on the display unit 53, a large load is not applied to the parallel bus 55, and a reduction in the processing speed of the CPU 51 can be prevented. Next, the configuration of the HDD 31 will be described with reference to FIG.
  • the HDD 31 includes a main function unit 41 and a serial bus control unit 42.
  • the main function unit 41-2 includes a magnetic recording disk 57 for recording data, and a recording / reproducing control unit 58 for recording / reproducing data on / from the magnetic recording disk 57 overnight. It is composed.
  • the serial bus controller 42 includes three boats 16. Each of these ports is numbered and distinguished from each other. Hereinafter, these three ports are numbered 1, 2, and 3.
  • other devices are configured to include a main function unit and a serial bus control unit.
  • the main function unit has a configuration for realizing the function of each device, but since this can be realized by a generally known configuration, the description of the configuration of the main function unit in these devices is omitted. I do.
  • a serial bus control unit 42 includes an arbitration control unit 61, a bucket receiving unit 62, a bucket transmitting unit 63, a bucket analyzing unit 64, and a bucket generating unit 6. 5, a node connection storage unit 66, a dummy signal generation unit 67, a port control unit 68, and a port transceiver 69.
  • the arbitration control unit 61 is for performing a process of acquiring the right to use the IEEE1394 bus.
  • the bucket receiving section 62 is for receiving and temporarily storing a bucket.
  • the bucket transmitting unit 63 is for transmitting a bucket.
  • the bucket analyzing unit 64 analyzes the type of the received bucket, the transmission source of the bucket, and the reception destination of the received bucket.
  • the above-mentioned bucket generating section 65 is only for generating a newly transmitted bucket.
  • the node connection storage unit 66 stores a connection relationship between the own node provided with the serial bus control unit 42 and another node connected via the IEEE1394 bus.
  • the dummy signal generation section 67 is for generating a dummy signal to be transmitted to a port that does not transmit a bucket.
  • the port transceiver 69 is for transmitting and receiving signals to and from the IEEE1394 bus.
  • the port transceiver 69 has two pairs of terminals A and B.
  • the pair A has a twisted pair 70 connected thereto, and the terminal pair B has a twisted pair 71 connected thereto.
  • two sets of differential signals are input to and output from the IEEE1394 bus.
  • the port control unit 68 is for setting the input / output operation of the port transceiver 69 individually for each port transceiver.
  • the bucket analyzing unit 64 first analyzes the received bucket, and obtains a source ID (identifier) indicating the node that transmitted the bucket (S I1).
  • the node number stored in the node storage unit 66 is compared with the node number indicated by the source ID, and a matching node number is detected (S12).
  • the detected node number is converted into a port number (first port number) connected to the node to which the node number is assigned (S13).
  • the conversion can be performed according to the information indicating the correspondence relationship described later (see FIG. 17).
  • a port number (second port number) of a port other than the port indicated by the converted port number among the ports provided in the own node is obtained (S14).
  • the dummy signal generation section 67 generates a dummy signal and sends it to the second port number obtained above (S15).
  • the dummy signal is generated and transmitted with lower power consumption than when a normal signal is generated.
  • One packet is sent as two pairs of differential signals between the two nodes. Each pair is represented by A and B. Furthermore, the signals of A and B are interchanged and connected.
  • the positive signal of A signal is A-P
  • the negative signal of A signal is A-N
  • the positive signal of B signal is B-P
  • the negative signal of B signal is B-N.
  • A—P of node m is connected to B—P of node n
  • A—N of node m is connected to B—N of node n.
  • BP of node m is connected to A-P of node n
  • BN of node m is connected to A-N of node n.
  • FIG. 8 is a table showing the correspondence between the differential voltage of A or B at the receiving end and the actual value on the signal lines 70 and 71, that is, the received value. If the positive / negative difference is greater than +168 mV, the received value is “1”. If the positive / negative difference is less than 1168 mV, the received value is “0”. If +89 mV, the received value is assumed to be “Z”.
  • the fact that the received value is “Z” means that the signal is driven from either the A or B node.
  • Nodes A and B drive signals with opposite polarities, for example, when not driven or when node A outputs a signal with positive polarity and node B outputs a signal with negative polarity Is either case.
  • FIG. 9 is a table showing the relationship between the reception value and the transmission value of the own node, and the transmission value of the partner node determined from the reception value and the transmission value.
  • the state indicated by the signal is combined with two sets of signals A and B, and information describing the state is transmitted and received.
  • each of the signals to be combined indicates one of the above “1”, “0”, and “Z”.
  • both A and B are “Z”, and when both A and B are “1”, it indicates the contents common to the setting on the transmitting side and the judgment on the receiving side. That is, if both A and B are “Z”, it indicates that the bus is unused.
  • This signal state is denoted as IDLE. If both A and B are “1”, it means that the bus is initialized and reconfigured. This signal state is expressed as BUS—RESET.
  • Fig. 11 among the combinations of the received values of the two signals ⁇ and ⁇ forming a pair, nine states are defined, and for each state, the signal state name and the meaning of the signal are defined .
  • the “RX—” at the beginning of the signal state name is a table that indicates reception. If multiple signal state names and meanings are defined for the same state, these are distinguished by the state generated by the signal received before. This distinction will be described below.
  • the state names after “TX” and “RX” are PARENT—NOT I FY, CHILD—N 0 TIFY, I DENT—DONE, and SELF.
  • One ID, one GRANT, one ROOT, one CONTENT ION, one PARENT, HANDSHAKE, and one CHILD, one HAND SHAKE are used only when resetting the bus immediately after a bus reset.
  • REQUEST and GRANT are used for arbitration to secure the right to use the bus during normal operation.
  • DATA-PRE FIX and DATA-END are used during bus reconfiguration and during bucket transfer during normal use.
  • nodes are connected in a ring shape, and there is a connection relationship of PARENT and CH I LD between the two nodes connected to each other.
  • PARENT sends a bus grant to CH I LD.
  • a hierarchy of connection relationships may occur. For example, in the system shown in FIG. 1, node # 2 is a PARENT of node # 0 and node # 1, and is a CH ILD of node # 3. At the highest level, the node without PARENT is called the root. In the system shown in Fig. 1, node # 3 is strong and becomes the root.
  • the B signal raises and lowers the signal level in accordance with the data bits "1" and "0" transmitted at regular time intervals.
  • the A signal is inverted when the same data continues in the B signal.
  • the data transfer rate is 98.304 Mb / sec.
  • se 1 f The ID bucket is used to determine the node number when reconfiguring the bus.
  • the 0th se1f—ID bucket is a phy-ID field that stores the node number and a gap that indicates the duration of the IDLE state required to detect unused buses.
  • Figure 13 B 13D 1st, 2nd, and 3rd se 1 f—ID buckets are used to reconfigure nodes with four or more ports, depending on the number of ports.
  • the bucket up to the required number is sent. That is, when the number of ports is j, j se1f-ID packets from the 0th to the (j1-1) th are transmitted.
  • the asynchronous bucket is configured to have at least an asynchronous bucket among a bucket header and a data block.
  • the bucket header includes destination-ID indicating the destination node number, source-ID indicating the source node number, tcode indicating the type of bucket, and packet-type specified for each type of packet. — Speci fic information, packet—type—speci fic quadlet data, and
  • the data block is composed of d ata, d ata _C R C for error detection, and power.
  • the isochronous bucket is mainly used for transferring a large amount of data while maintaining a constant data transfer amount per unit time, such as for moving image reproduction.
  • data is distributed to multiple buckets of equal capacity.
  • the isochronous bucket is configured to include a bucket header and a detachable packet.
  • the bucket header includes ch anne 1 indicating a channel number, t c o de indicating a packet type, and he ad e r one C R R for detecting occurrence of an error during transmission.
  • the channel number indicated by channe 1 above specifies the destination and the source node.
  • the data block includes d ata and d ata — C R C for error detection.
  • the ACK bucket is a packet indicating that an asynchronous bucket has been received. Immediately after receiving the asynchronous packet, the packet is transmitted while the sender of the asynchronous bucket has the right to use the bus. Sent.
  • the ACK packet is composed of a 4-bit ac k—co d e and a 4-bit a c k_p a r ty which is a two's complement of a c k—c o de.
  • the above ack_pality is used to detect an error contained in the read bit.
  • connection state of the nodes stored in the node connection storage unit 66 (see FIG. 6) will be described with reference to FIGS.
  • this information is stored in a table format, and the node numbers are stored in association with the numbers of the ports to which the corresponding nodes are directly or indirectly connected.
  • this information is stored in a table format, and includes the channel number specified in the asynchronous packet and the number of the port to which the source and destination nodes are directly or indirectly connected. Are stored in association with each other.
  • an isochronous bucket may be sent to multiple nodes, multiple ports are associated with one channel number and sent to a port set to "1". .
  • the bus in the initial state, the bus is in the BUS-RESET state.
  • connection relation of the tree structure is set.
  • CH I LD—NOT I FY is output to 32 and CD—ROM 33, and HDD 31 becomes a PARENT of HDD 32 and CD—ROM 33.
  • CH I LD— NOT I FY is output to 32 and CD—ROM 33, and HDD 31 becomes a PARENT of HDD 32 and CD—ROM 33.
  • HDD 31 Upon receiving LD—NOT I FY, HDD 31 sends PARENT—NOT I FY
  • PC 30 stops outputting CH I LD N 0 TIFY and sets the tree structure. The connection of the structure is determined.
  • the node that first outputs PARENT—NOT I FY and the output of HDD 32 and CD—ROM 33 may be any node that is connected to only one node, and may be any number of nodes. Even in such a case, it is needless to say that the connection relation can be set by a procedure similar to the procedure described above.
  • the root PC 30 outputs GRANT to the HDD 31.
  • the HDD 31 Upon receiving the GRANT, the HDD 31 outputs a GRANT to the HDD 32 of the port number 2 of the two CH I LDs, and outputs a DAT A—PREF FIX to the CD—ROM 33.
  • the HDD 32 that has received GRANT has a node number of 0 because it has not received any se 1 f—ID packet yet.
  • the HDD 32 transmits a DATA-PREFIX, a seIF-ID packet indicating the node number 0, a DATA-END, and an IDENT-D0NE signal to the HDD 31 in this order.
  • the HDD 31 transfers the DATA-PREFIX from the HDD32, the se1f_ID bucket indicating the node number 0, and the DATA-END to the PC 30 and the CD-ROM 32.
  • HDD 31 When HDD 31 receives IDENT-DONE, it transmits DATA-PREFIX to HDD 32 at time t205 and stops outputting DATA-END to PC 30 and CD-ROM 33. When the HDD 32 receives the DATA-PREFIX, the HDD 32 stops outputting the IDENT-DONE signal, and the assignment of the 0th node is completed. At this time, the HDD 31 receives the ID bucket indicating the node number 0, se 1 f—The ID bucket is received at the port number 2, so that the node 0 is connected to the second port. Record in the management table.
  • the PC 30 outputs GRANT again (time t206), and starts setting the next node number.
  • the HDD 31 receiving the grant also transfers the grant to the CD-ROM 33 for which the node number has not been determined.
  • CD—ROM 33 is a se 1 f ID
  • the node number is 1 because one packet was received.
  • DAT A- PRE FIX, se 1 f_ID bucket indicating node number 1, D ATA—END, and I DENT—DONE are output, and the first node is assigned.
  • the application is completed.
  • the HDD 31 receives the se 1f—ID bucket indicating the node number 1 on the port number 3, so that the node connection storage unit 66 confirms that the first node is connected to the third port. (See Fig. 6) Record gc in the node connection management table in.
  • the second node number is similarly assigned to HDD31. Since the second node is the HDD 31 itself, “0” is set as the port number to indicate that there is no connected port. Record on the table.
  • the PC 30 determines that the setting of the numbers of the HDD 31 and all the nodes connected thereto has been completed, and gives the third node number to itself. Assigned, self-ID packet with node number 3 notifies other nodes by ID packet.
  • the HDD 31 records that the third node is connected to the first port in the node connection management table in the node connection storage unit 66 (see FIG. 6).
  • connection information indicating the configured connection state is recorded in the node connection storage unit 66 (see FIG. 6).
  • node numbers are set as shown in parentheses in FIG.
  • the PC 30 vigorously outputs DATA-PREF IX, an asynchronous bucket from the third node to the 0th node, and a DATA-END signal. Send to HDD31.
  • HDD 31 sends data PRE FI from the node number of the source and destination via the second port to which HDD 32 is connected, and syncs from node 3 to node 0. Transfer the NAS bucket and the DATA-END signal. At the same time, the HDD 31 receives the DATA-PREF IX signal generated by the dummy signal generator 67 (see Fig. 6) from the third port to which the CD-ROM 33 is connected. (DC voltage) is output. As a result, bucket transmission from the CD-ROM 33 is prevented.
  • the HDD 31 sends the data to the PC 30 that is the source of the immediately preceding cascade packet. To transfer. At this time, the HDD 31 continues to transmit DATA-PREF IX to the CD-ROM 33.
  • the HDD 31 finishes outputting the DATA-END signal to the PC 30 and also stops transmitting the DATA-PREFIX to the CD-ROM 33.
  • the CD-ROM 33 detects that the bus IDLE state has continued from the time t303, and outputs a RE QUEST signal requesting the right to use the bus.
  • the CD-ROM 33 transmits the DATA-PREF IX, the asynchronous bucket from the first node to the third node, and the DATA-END signal.
  • the HDD 31 transfers these to the PC 30 and sends a DATA-PREF IX signal to the HDD 32.
  • PC 30 returns an ACK packet
  • HDD 31 sends DAT A__P to HDD 32 until transmission of DAT A-END to CD-ROM 33 is completed. REFIX continues to be sent.
  • the channel number is determined, the bucket is passed only to the required port, and a DATA- PRE FIX signal is output to the other ports.
  • the DATA-PREFIX signal is released without waiting for the ACK bucket.
  • a DC-less DATA- PRE FIX signal is transmitted to a port that does not need to transmit a bucket, waste of power consumption for transmitting a high-speed bucket is reduced. it can.
  • a signal with a frequency lower than that of a normal bucket signal should be used as a signal to suppress the transmission of a bucket from that port, as long as no other node detects an empty bus.
  • the HDD 31 does not output any signal to the CD-ROM 33 from time t301 to time t303, the CD-ROM 33 determines that the bus is in an unused state. And output a REQUEST signal.
  • the CD-ROM 33 can be made to wait if the REQUE ST signal is ignored by the arbitration control unit 61 in FIG. 6 until the time t 304 of the HDD 31. Therefore, even in this case, the same effect as the above-described procedure can be obtained.
  • INDUSTRIAL APPLICABILITY The present invention is applicable not only to the bucket transmission system but also to all systems for transmitting data between nodes using a bus.

Abstract

Un noeud connecté au-delà d'un port est mémorisé, et la destination d'un paquet est discriminée. Un paquet est ainsi transféré à un port qui nécessite le transfert d'un paquet, tandis qu'un signal factice, présentant une puissance de dissipation plus faible que lors de la transmission du paquet, est envoyé à un port qui ne nécessite pas de transfert de paquets. Ainsi, la consommation de puissance accompagnée par le transfert d'un paquet à un noeud inutile est réduit dans un état dans lequel on évite toute collision de bus.
PCT/JP1998/001876 1997-04-30 1998-04-23 Dispositif de commande de bus et systeme de traitement de l'information WO1998049807A1 (fr)

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JP9/112466 1997-04-30
JP11246697A JPH10303949A (ja) 1997-04-30 1997-04-30 バス制御装置および情報処理システム

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WO1998049807A1 true WO1998049807A1 (fr) 1998-11-05

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PCT/JP1998/001876 WO1998049807A1 (fr) 1997-04-30 1998-04-23 Dispositif de commande de bus et systeme de traitement de l'information

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JP (1) JPH10303949A (fr)
WO (1) WO1998049807A1 (fr)

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JP3277887B2 (ja) 1998-06-19 2002-04-22 日本電気株式会社 送受信方法、送受信回路および送受信回路の制御方法
JP2006115315A (ja) 2004-10-15 2006-04-27 Fujitsu Ltd データ転送方法及びデータ転送装置

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