CN1241080A - Method and apparatus for transmitting data over data bus at maximum speed - Google Patents
Method and apparatus for transmitting data over data bus at maximum speed Download PDFInfo
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Abstract
A method and apparatus for transmitting data among devices connected to a serial data bus at maximum speeds are disclosed. A transmitting device first transmits a data packet to a target recipient device at a maximum transmission speed of the transmitting device. If an acknowledgement signal confirming receipt of the initial data transmission is received from the target recipient, then the transmission speed for subsequent data packet transmissions's set to the speed of the just-transmitted data. Otherwise, the transmission speed is reduced and the process is repeated. Once an acknowledgement is received and the speed is set, the speed may be stored in a memory of the transmitting device for use in future communications with the recipient device. The process is repeated to establish maximum suitable transmission speeds to other target devices connected to the bus. The invention has particular utility when used in conjunction with an IEEE 1394 serial bus interface in the absence of a bus manager.
Description
The present invention relates generally to data communication, and each special equipment that is specifically related to be connected to data/address bus can send data to a kind of technology of other equipment with maximal rate.
Because a kind of trend appears in " intelligence " device proliferation in recent years, promptly can be by being connected to common data bus and another devices communicating such as daily electronic equipments such as video tape recorder (VTR), TV, personal computers.In many considerations of carrying out this data communication, the first is selected suitable data transmission speed.When the equipment that is connected to common bus has different data signaling rate abilities, must select transmitting terminal can send the data transmission speed that data and receiving equipment can receive data.And if exist in another equipment (trunking) between the transmitting and receiving device, the data transmission speed of then selecting this trunking to work is necessary.
Issued that international I/O connects standard, promptly IEEE 1394-1995 serial bus standard carries out the puppy parc that bus data is communicated by letter so that provide by serial.The digital interface of this protocol definition data communication, therefore need be before not sending through bus be the application of analogue data with digital data converting.Equally, receive using will be from bus receiving digital data rather than analogue data, and therefore will not need to carry out the A/D conversion.
Adopted IEEE 1394 standards to realize the cheap high speed architecture of supporting that asynchronous and synchronous the two formatted data transmits.Synchronous data transmission is real-time transmission, transmits like this to make and use the two and have the identical duration sending and receive in effective time interval between the situation.Each packet of synchronous driving transmitted in its time cycle.An example for the application of synchronous data transmission is from video tape recorder to a television set.This video tape recorder document image and sound and chunk or these data of grouping preservation to disperse.Then this video tape recorder transmits the image that is illustrated in the finite time periodic recording and each grouping (packet) of sound during that time cycle, so that shown by television set.The synchronous data transmission of a plurality of channels between being used to use is provided.One six bit channel number is broadcasted so that guarantee the reception of suitable application with data.This makes a plurality of application side by side send synchrodata by bus structures.Asynchronous communication is traditional data transfer operation, and it carries out as soon as possible and data volume is sent to the destination from the source.
Figure 19 is the arrangement with a plurality of equipment of the information processing capability that is connected to IEEE 1394 universal serial bus.In this example, IEEE 1394 universal serial bus 10-1 are to the interconnected personal computer of 10-7 (PC) 1, comprehensive receiver/decoder (IRD) 2, digital video tape recorder (digital VTR) 3, editing machine 4, miniature disc record (MD) group 5, monitor 6, hard disk drive (HDD) 7 that is used for storing image data and voice data and server 8.These equipment have satisfied IEEE 1394 standards and IEC 61883 standards that send based on audiovisual (AV) data of IEEE 1394 are provided.The equipment of each connection is formed the node (that is, an addressable unit) among the IEEE 1394, and each equipment its maximum data communication speed of having that it can carry out that data send and receive.According to IEEE 1394 standards, can be one of 98.308Mbps, 196.608Mbps or 392.216Mbps for giving the maximal rate of locking equipment arbitrarily, be appointed as S100 respectively at this, S200 and S400.Certainly, the maximum data communication speed of a particular device depends on the hardware capabilities of this equipment.An equipment can be always to transmit and receive data than low velocity; For example, if desired, the equipment with S400 ability can be with S100 or S200 communication.Data based on S100 send and can be carried out by all devices that satisfies IEEE 1394 standards.When the equipment with different maximum communication speed was connected to a common bus, transmitting apparatus must be can being that the transmission speed of another equipment relaying of repeater sends by work.
Figure 20 exemplarily describes the maximum data communication speed for the equipment of Figure 19.Therefore, PC1 has maximum data communication speed S400; Editing machine 4 has maximum data communication speed S200 etc.For example, MD group 5 and digital VTR 3 are S400 equipment, and are free of attachment to the equipment that transmits data between them, so they are always communicated by letter with S400 speed each other.On the other hand, if a slower equipment work is a repeater of equipment faster, so this equipment can not be with its maximal rate ability by this trunking and other devices communicatings faster.For example, the two can send MD group 5 and PC1 with S400, but because only having the receiver/decoder 2 of S200 ability is connected between their transmission path, so they can only be communicated by letter with S200 speed.
Function that is called " bus manager " of IEEE 1394 serial bus standards definition, this bus manager is carried out professional: High Tributary Bus capacity (power) management; The maintenance of the hodograph of the data signaling rate ability of the equipment that bus connects; The maintenance of the topological diagram of connection device; Bus optimization based on the information that obtains from this topological diagram.As the part that bus is optimized, this bus manager determines to consider that each equipment of current topological structure can send the maximal rate of data.This bus manager provides according to this optimization has maximum data transmission speed information to each equipment.Like this, according to the information from bus manager, the setting that is connected to IEEE 1394 universal serial bus groups has the data transmission speed that sends for the data to a particular device that is connected to this bus.By this way, the maximum data transmission speed executive communication communicating by letter.When increasing a new equipment or when bus is removed an equipment, renewal speed figure and the data speed information that offers bus connection device.
IEEE 1394 standards also need an entity that is called synchronous data management device.This entity function provides facility to be used for: the distribution of synchronization bandwidth; The distribution of channel number; And the selection of loop-body (cycle master).
According to IEEE 1394 serial bus standards, the existence of bus manager is optional.But if bus manager does not exist, then Isochronous Resource Manager is fulfiled generally the subclass of the management responsibility of being born by bus manager.(synchronous communication is carried out in the situation supposition of back.If there is not Isochronous Resource Manager, then do not allow synchronous communication).In this case, if the equipment on IEEE 1394 universal serial bus has S200 or higher ability, then this equipment must still be carried out the initial communication based on S100, because they can not obtain the information for the proper data transmission speed of the equipment of receiving terminal.Like this, when bus manager did not exist, a problem occurred, that is, the equipment that is connected to IEEE 1394 universal serial bus uses minimum speed to carry out data and sends.
An object of the present invention is to provide the method that in being connected to the equipment of common bus, sends data with maximal rate.
Even another object of the present invention provides the method that sends data in the equipment of IEEE 1394 serial data bus not having to be connected under the situation of bus manager.
A further object of the present invention provides a kind of equipment that is connected to data/address bus that can be identified for to the suitable transmission speed of other equipment sending datas that are connected to bus.
Another purpose of the present invention provides for a kind of of the data communication on the data/address bus improves one's methods.
According to an exemplary embodiment of this invention, be provided at the method and apparatus that sends data in the equipment that is connected to data/address bus with maximal rate.Each equipment possibility can be with multiple speed sending data.Transmitting apparatus is at first with the maximum transmission speed of this transmitting apparatus, and the packet that sends the id information with receiving equipment is to bus.If receive a confirmation signal that confirms to receive the primary data transmission, then be set to send just now the speed of data for the transmission speed of the follow-up data that sends to that equipment from the target receiving equipment.Otherwise, reduce this transmission speed and repeat this processing.In case receive the confirmation and be provided with this speed, then this speed can be stored in the memory that is used for receiving equipment is carried out the transmitting apparatus of follow-up data transmission.It can be asynchronous that follow-up data sends and/or synchrodata sends.Repeat this processing, to be established to the maximum suitably transmission speed of other target receiving equipments that are connected to this bus.
The present invention has a kind of special purpose when using in conjunction with IEEE 1394-1995 serial bus interface under the situation that does not have bus manager.Comprise in removing after the bus reset operation of memory of each equipment of transmission speed information, single equipment is where necessary by sending the proper data transmission speed that divides into groups to rebulid for each other equipment with the speed that changes, up to receiving the confirmation from each corresponding apparatus.
To understand well in conjunction with the accompanying drawings by example and provide and do not attempt to limit fully and describe in detail below of the present invention, identical in the accompanying drawings label is represented components identical and parts, wherein:
Fig. 1 is the hardware block diagram in the digital VTR;
Fig. 2 is the functional-block diagram of digital VTR according to an embodiment of the invention;
Fig. 3 is the block diagram of explanation according to the function of IEEE 1394 agreements execution;
Fig. 4 is the block diagram of expression asynchronous child-operation (subaction) structure;
Fig. 5 is the block diagram of the expression node state that begins to arbitrate;
Fig. 6 illustrates the nodal operation that receives request signal;
Fig. 7 is the block diagram that the operation of the node that can be used as root when the node output enabling signal is described;
Fig. 8 illustrates the operation of the node that receives enabling signal and receives the operation of the node of refusal signal;
Fig. 9 is the block diagram of explanation state of node when node begins the data transmission;
Figure 10 explanation sends and receives in the message between the link layer during the asynchronous communication;
Figure 11 is the block diagram of the synchronous child-operation structure of expression;
The loop that the data of Figure 12 explanation in the equipment that connects based on IEEE 1394 send;
Figure 13 describes an asynchronous packet example of structure;
Figure 14 is the table of the master unit of an asynchronous packet of explanation;
Figure 15 describes affirmation-packet configuration;
Figure 16 is a table of describing the difference affirmation code of an asynchronous packet;
Figure 17 illustrates according to the present invention by sent data to the flow chart of the processing of a receiving device that is connected to bus by a sending ending equipment;
Figure 18 is explanation sends another processing of data according to the present invention a flow chart;
Figure 19 represents to be connected to the arrangement of the various device of IEEE 1394 universal serial bus; With
Figure 20 describes the arrangement of the equipment of the various data speed abilities that are connected to bus.
Now from being used for describing the preferred embodiments of the present invention at the equipment of IEEE 1394 universal serial bus execution high-speed data transmission and the angle of method.But, can consider that the present invention can realize in conjunction with other data bus protocol.Therefore, following detailed only is to be used for illustration purpose.
Referring now to Fig. 1, the functional-block diagram of a digital video tape recorder (VTR) is shown.Hereinafter will describe as the digital VTR 3 that is configured on data/address bus, send data to the exemplary information treatment facility of each receiving equipment with maximal rate according to the present invention.But the device of the data communication technology of the execution novelty that adopts in VTR 3 can be incorporated in any messaging device that is connected to bus.
Fig. 2 is the functional-block diagram of the program mainly carried out by the CPU 25 among the digital VTR 3 with above-mentioned hardware (or be connected to other equipment of the universal serial bus).Record/playback unit 21 controlling recording and resetting/from the mass media memory cell, for example data of videotape in this example.Communication speed is provided with unit (transmission speed setting device) 32 from being used to send data to the transmission speed 98.308Mbps of a target receiving device that is connected to this bus, selects a predetermined transmission speed among 196.608Mbps and the 392.216Mbps.Speed is provided with unit 32 and requires serial bus control unit (data sending device) 35 to carry out the data transmission with the transmission speed of selecting.An affirmation (ACK) detecting unit 33 (checkout gears) detect the affirmation signal from this target receiving device, and this signal sends the reception that sends to that equipment with authentication data by VTR 3.According to the received signal that is detected by ACK detecting unit 33, whether communication speed unit 32 specified datas can be sent to the target receiving device with the transmission speed that sends grouping.
Communication speed memory cell 34 (transmission speed storage device) storage is corresponding to the maximum transmission speed table of each equipment that is connected to this bus.The speedometer registration of each storage is according to the speed that can suitably be sent to relevant equipment by VTR 3.By speed unit 32 is set and determines speed according to the affirmation signal that sends from each receiving equipment.(according to these IEEE 1394 standards, no matter when increase equipment removal equipment on bus or on this bus this bus that all automatically resets) when " reconfiguring " or " resetting " IEEE 1394 universal serial bus, speed memory cell 34 is eliminated canned datas.Series bus controller 35 has the communication protocol based on IEEE 1394, or from being connected to other equipment receiving datas and the confirmation signal of IEEE 1394 universal serial bus.
With reference to Figure 17 and Figure 18 the method for optimizing to the data transmission speed of a target receiving equipment that is provided with by speed that unit 32 determines is described subsequently.In brief, these method for optimizing needs at first send data to a target receiving equipment, the VTR3 in this example with the maximum transmission speed of this transmitting apparatus.If receive this to the affirmation that primary data sends from this target receiving equipment, then Xuan Ding transmission speed is maximum transmission speed (for example speed S400); Otherwise, select next lower speed (S200) to carry out the data transmission of attempting as candidate with S200.If receive the confirmation for lower data transmission, then select the data transmission speed of S200 as future; Otherwise, select speed S100.When attempting to send to another target device, repeat this processing.Correspondingly, the maximum data communication speed is set in an efficient way not needing bus manager to provide under the situation of velocity information.
1394 communication protocols
In order to understand the present invention better, some aspect of this agreement will be described now for adaptability according to the equipment of IEEE 1394 protocol communications.Provide the embodiment of the data communications method of this invention subsequently.
Fig. 3 is the block diagram of explanation according to the functional layer structure of IEEE 1394 agreements.This protocol definition is by three layers of hierarchy of forming, and these three layers are: affairs processing layer 42, link layer 43 and physical layer 44.Can think that these three layers exist in each node that is connected to universal serial bus.Each layer communicates with one another, and every layer can be communicated by letter with an optional serial bus management entity 41.Affairs processing layer 42 and link layer 43 each layer and another functional block (for example, shown in Figure 2 record/playback unit 31) communication.In this communication, use transmission/reception message of four types: request; Indication; Response; And affirmation.Arrow shown in Figure 3 is represented these communication.Wherein " .reg " is added to each request of communication expression and affirmation of " .conf " expression of arrow title end.For example, " TR CONT.reg " expression sends to a request communication of affairs processing layer 42 from serial bus management 41.
Fig. 4 is the figure of the arrangement of the asynchronous child-operation of address in expression specified node ID and the node.In this example, in the time cycle that is expressed as " child-operation 1: request ", the first predetermined node transmits a grouping so that ask second destined node to carry out read or write.In the interval of expression " child-operation 2: response ", the Section Point response is from the request of first node.This asynchronous child-operation is formed by arbitrating sequence 51-1 and 51-2, packet transmission 52-1 and 52-2 and affirmation 53-1 and 53-2.The node request physical layer 44 that transmits an asynchronous packet is at arbitration sequence period control IEEE 1394 universal serial bus such as 51-1 or 51-2.Node successful in arbitration transmits an asynchronous packet in such as the packet transmission cycle of 52-1 or 52-2.The node that receives the asynchronous packet of specifying its receiver node ID sends a confirmation signal to the node that sends this grouping in such as the affirmation cycle of 53-1 or 53-2.Packet sends 52-1 and 52-2, is separated by the cycle that is called " ACK at interval " 52-1 and 52-2 with relevant affirmation 53-1 and 53-2.
Be described in the operation of the physical layer 44 of each node in the cycle of arbitrating sequence 51-1 and 51-2 now with reference to Fig. 5-9.Fig. 5 utilizes request msg to send and some node specification of beginning to arbitrate is connected to the condition of the node of IEEE 1394 universal serial bus.(condition of contact of Fig. 5 is different from condition of contact shown in Figure 19.) supposition is after detecting the child-operation interval, node #0 and #2 export the father node of request signal to them respectively simultaneously, that is, and and node # 4 and #3.No matter when father node (first father node) receives request from a child node, unless another child node of first father node has been made request, otherwise this father node is exported this father node of asking it (second father node), if this father node exists.That is, first father node is exported the request from the child node of at first making this request, and sends the child node of a refusal signal to other simultaneously.
Therefore, as shown in Figure 6, because node # 3 receives request signal from node # 2, it sends this and asks its father node node # 4, and sends the child node of a refusal signal to other, i.e. node # 1 simultaneously.For instance, when the request from node #0 arrived node # 4 prior to the request from node #3 (it comes from node # 2 request), a refusal of node # 4 output signal was to node #3.It should be noted that node #0 in this example, #1 and #2 are designated as leaf node, because they can only be connected to another node.Node # 3 is that a branch node and node # 4 are root nodes.Usually, the selection of root node is not rely on topological structure, and even also is that a leaf node is acceptable for root node.But it also must be this root that this standard needs the synchronous circulation main body, because this root has the highest natural priority power.And the node with all its connectivity ports of the child node of being identified as becomes root.
As shown in Figure 7, permit signal as one of the node # 4 output of root and give node #0, node #0 has exported request signal the earliest.When a root node provided child node to it of enabling signal, it exported the residue child node that the refusal signal is given it simultaneously.Equally, root node # 4 sends a refusal signal to the branch node # 3 in present example.Branch node # 3 does not continue to export this request signal to this root node when receiving this refusal signal, and sends refusal signal each child node to it, i.e. node # 1 and node #2.Node # 2, when receiving this refusal signal, the output of its request signal of end as shown in Figure 8.
It is a data prefix signal that the node of the enabling signal of its request signal of reception response changes this request signal.As shown in Figure 8, in present example, node #0 is when root node # 4 receives this enabling signal, and changing this request signal is a data prefix signal.When node # 4 received this prefix data signal, as shown in Figure 9, it finished the output of this enabling signal.The similar part of the effect of refusal signal and prefix data signal is no matter when a node receives a refusal signal or a data prefix signal, and it all enters a receiving mode.Therefore, node # 1 and #4 begin to be in before data send their receiving mode at node #0.Data along prefix data sense transmission shown in Figure 9 from node #0 output are to all nodes.
The operation of link layer 43, wherein specified node ID and node address when Figure 10 explanation is carried out the asynchronous message transmission and received when them.The affairs processing layer 42 of a sending node sends the link layer 43 of a request message to that node.Then sending node link layer 43 link layer 43 that forwards packets to this target receiving node through the physical layer and IEEE 1394 universal serial bus of this transmission and receiving node.Next step, receiving terminal link layer 43 sends an Indication message to receiving terminal affairs processing layer 42, and this receiving terminal affairs processing layer 42 is beamed back by physical layer and universal serial bus again and is confirmed that 53-1 gives the reception of transmitting terminal link-layer acknowledgment raw requests.Transmitting terminal link layer 43 is by sending an acknowledge message to 42 these affirmations of response of transmitting terminal affairs processing layer.
Like this, in aforesaid way, when sender node received an affirmation, the data communication of the receiving node that it is known and expects was set up, and can asynchronously carry out.On the other hand, when transmitting terminal can not detect affirmation, it determined that this situation is that ACK loses, and means the communication failure of trial.
Turn to Figure 11 now, a sequential chart of the synchronous child-operation that furnishes an explanation.Utilization is at a specific time slot or " channel ", and for example, each grouping that sends during first to the 3rd channel of narration is carried out synchrodata and sent in grouping.Continuous channel such as first and second channels can support packet to send by different mode or by model identical.Child-operation is made up of to 62-3 to 61-3 and the transmission of the packet in each channel 62-1 arbitration sequence 61-1 synchronously.Send its physical layer of node request 44 control IEEE 1394 universal serial bus in the arbitration sequence period of synchronized packets.The operation of each node is identical with the aforesaid operations of node in asynchronous child-operation in each synchronous child-operation.
Successful sending node sends a data prefix and isochronous data packet such as 62-1 immediately in the arbitration in the follow-up time cycle during the arbitration sequence of for example 61-1.This synchronous child-operation is divided to 63-4 by synchronous gap 63-1 to be opened, and this gap is shorter to 54-3 than the asynchronous child-operation gap 54-1 of Fig. 4 discussed above.Want the node of synchronized transmission data to incite somebody to action immediately for the bus arbitration after the detection in synchronous gap.Want the node of asynchronous transmission data must wait for that asynchronous gap occurs.Because this synchronous gap is shorter than asynchronous gap, this gives the priority that synchronous communication is higher than asynchronous communication.
Figure 12 is described in the cycle that data send in the equipment that connects based on IEEE 1394 standards.With data be divided into the grouping and the 125 microsecond cycles of using send as benchmark.Set up this cycle according to the one-period commencing signal that provides from node with cycle main functionality.Synchronized packets keeps for the essential frequency band of the transmission that begins from all cycles (being time slot).Therefore, for synchronized transmission, the data the Fixed Time Interval that guarantees to begin from this cycle send.But, if send wrong the appearance, then owing to not using protection system to lose data.In case want all nodes of synchronized transmission data to do like that, for example, to N, this bus will be in and idle occur up to asynchronous child-operation gap at channel J.When this gap occurred, wanting to send the node of asynchronous data can arbitration bus and then asynchronous packet of transmission when arbitrate successfully.Asynchronous transmission uses affirmation and retry signal so that guarantee to send safely, regularly is fixing but transmission can not be set.
Turn to Fig. 3, the logical symbol that physical layer 44 will be used in link layer 43 is transformed to the signal of telecommunication.Physical layer 44 is used arbitration to guarantee to have only a node to begin data and is sent.It carries out reshuffling of IEEE 1394 universal serial bus according to bus reset, and specifies physics ID automatically.
Serial bus management entity 41 is realized the essential bus controlled function, and the control and the status register structure (CSR) of ISO/IEC 13212 standards are provided.Serial bus management entity 41 has the function of Node Controller, Isochronous Resource Manager and bus manager.This Node Controller Control Node state, node ID etc., and control affairs processing layer 42, link layer 43 and physical layer 44.For carrying out synchronous communication, at least one equipment that is connected to IEEE 1394 universal serial bus must have isochronous resource manager function.Bus manager is the highest function of each function, and its objective is the best IEEE of use 1394 universal serial bus.The existence of Isochronous Resource Manager and bus manager is optional.But according to this standard, if there is not bus manager, then Isochronous Resource Manager is carried out the subclass of the management function of normally being born by bus manager.Certainly, if Isochronous Resource Manager does not exist yet, so only carry out asynchronous data communication.
Referring now to Figure 13,, the exemplary configurations of an asynchronous packet 52-1 or 52-2 is shown.This grouping is with destination ID (destination ID) beginning of the ID that wants receiving node, and finishes with data CRC (data CRC) field.This asynchronous packet is used for the data that send as pay(useful) load are write the address that begins with a predetermined skew receiver address.Each element characteristics of an asynchronous packet is provided in the table of Figure 14.The item of listing in the row under stem " NAMES (title) " is corresponding to the title of this asynchronous packet shown in Figure 13." CONTENTS (content) " row provide the Short Description of each unit.A node that can receive asynchronous packet reads the information that is stored among this receiver ID.When the ID of the ID that reads and this node coupling, this node begins to receive the content of this asynchronous packet.Then this receiving node confirms that by sending one grouping responds this sending node to this transmitter node (it sends this asynchronous packet) according to the information that is stored among the transmitter ID.
Figure 15 illustrates the affirmation grouping 53-1 of Fig. 4 or the structure of 53-2.Four least significant bits of this affirmation grouping are assigned to parity check bit.According to its code value, this ack code represents one of following state to four highest significant positions of this grouping: finish as " ack code (affirmation code) "; Hang up; Three types hurry; Or two types data error.Explain these states with reference to Figure 16.A node of transmitting terminal sends an asynchronous packet to one of receiving terminal predetermined node with a predetermined data transmission speed.When this transmitting terminal when receiving terminal receives grouping with any one ack code shown in Figure 16, its determines that the data that can carry out the node that is positioned at receiving terminal node send.(this receiving terminal node is designated as Figure 16's " Transmitter Node " (" transmitter node ").) when this receiving terminal node transmission comprised asynchronous packet of any one ack code shown in Figure 16, this represented the transmission speed that this receiving terminal node identifies the asynchronous packet of this reception and supports this asynchronous packet.As previously mentioned, according to IEEE 1394 standards, if bus manager exists, it keeps the hodograph of the topological structure of present interconnecting nodes, and provides predetermined velocity information to each node.Do not having under the situation of bus manager, the predetermined speed that each node sends data is minimum speed S100.
The embodiment of data transmission speed optimal method:
Figure 17 is explanation sends the method for data in being connected to the equipment of bus with maximal rate according to the present invention the flow chart of embodiment.This embodiment has special use for the situation that bus manager exists.If bus manager exists, then this method will preferably replace the standard technique that the predetermined speed that will send data offers the bus manager of each node.Disclosed here this method comprises with maximal rate transmission asynchronous packet to a target receiving equipment.If receive a suitable affirmation, then carry out the follow-up data transmission of receiving equipment with maximal rate, that is, asynchronous and/or synchronous.Otherwise, reduce transmission speed gradually up to receiving suitable affirmation.
By the example of this method is described, suppose that the digital VTR 3 of Fig. 1 and 2 is connected to a for example data bus of IEEE1394 bus, and plan sends data to a target receiving equipment (node) that is connected to this bus.But, be appreciated that the equipment of any type that is connected to universal serial bus can utilize appropriate software and/or hardware to realize this method so that realize each function.
At step S11, communication speed is provided with the maximum transmission speed that unit 32 request series bus controllers 35 are provided with the transmission that can carry out.Like this, for example, if sending node can then be initially set to S400 with this speed with S400 speed, and no matter be connected to the topological structure of the node of bus.At step S12, the node ID of series bus controller 35 by being included in this grouping target device in sending etc. send an asynchronous packet to the target receiving equipment with the transmission speed of equipment.This asynchronous packet can be with identical based on the grouping 52-1 of Fig. 4 in the system of IEEE 1394, and will follow the arbitration 51-1 of a success.At step S13, this ACK-detecting unit 33 determines that whether having received one from this target receiving equipment confirms grouping.For example, if reception has the grouping of one of ack code of Figure 16, then can detect the successful reception of confirming grouping.If received a suitable affirmation grouping, then processing finishes because the equipment of receiving terminal receives this asynchronous packet.Under this situation, the speed of the grouping that the transmission speed that sends for the follow-up data from VTR 3 to receiving equipment is set to be identified (that is, confirming that this maximal rate of response sends if receive one, then is S400 in this example).
If do not receive the confirmation grouping at step S13, then ACK-detecting unit 33 sends expression and to communication speed unit 32 is set from an Ack-missing (Ack loses) message that this target receiving terminal does not receive response.When communication speed is provided with unit 32 and receives these message, it determine the present transmission speed that is provided with by series bus controller 35 whether be minimum value (based on S100 98.308).If not minimum value, then program enters step S15, and communication speed is provided with unit 32 request series bus controllers 35 next lower transmission speed is set herein, for example, and 196.608Mbps (S200).In case lower transmission speed is set, and then program enters step S12, and repeat this process.
If at the present transmission speed of step S14 is minimum value, then program turns back to step S12, and carries out this processing once more as retry operation with minimum speed.Behind number of times, typically produce a communication failure error message with minimum speed retry regulation.
In the above example, suppose a specific transmission speed for once data reduce this transmission speed after send attempting.Before reducing this speed, can or repeatedly attempt revising this method in each two of speed permission.
As mentioned above, according to top embodiment, an equipment that for example is connected to the digital VTR 3 of a universal serial bus can be carried out data and send to a predetermined equipment on this bus can carry out maximum transmission speed that data send.When this transmitting apparatus wished to send data to one second receiving equipment, the second evaluation method selecting optimal equipment ground repeated the method for Figure 17.Attention is in the method for Figure 17, in case be accomplished to the data of target receiving equipment sends with the speed that is provided with, velocity information for that receiving equipment can be stored, and the data that are used for the future of that equipment send (supposing that this node is connected topological structure does not change), and are perhaps deleted.Under latter event, the data of at every turn carrying out this target device repeat the processing of Figure 17 when sending.
Figure 18 is the flow chart of the similarity method that sends of asynchronous data that explanation utilizes the node of the digital VTR 3 for example be connected to data/address bus to carry out another equipment.This method comes down to special circumstances of the method for Figure 17.That is, only be determined to the maximum transmission speed of a specific receiving equipment, that speed is stored in the memory of this transmitting apparatus, and is used for the following data transmission of this specific receiving equipment.But, reconfigure if carry out bus, then from this memory, eliminate this velocity information.Usually, no matter when increase equipment to bus or on the bus removal equipment all carry out bus and reconfigure.
The method of Figure 18 supposition sending node keeps comprising a memory of the storage transmission speed of some or the every other equipment that are used to be connected on this bus, for example, and communication speed memory cell 34.That is, each record of the storage transmission speed relevant with receiving equipment is to be suitable for the maximal rate that the data from the sending node to the receiving equipment send.When the execution bus reconfigures, eliminate this velocity information the memory of each equipment on being connected to this bus.In case this situation takes place, and can be carried out the method for Figure 18 by each equipment that is connected to bus immediately, so that set up the suitable transmission speed of subsequent communications immediately.Another kind of scheme, this method can only carry out for locking equipment before hope sends data to a predetermined receiving equipment by one.At latter event, after the generation bus reconfigures, the memory of giving locking equipment that comprises the storage transmission speed can partly or entirely keep empty, and this memory becomes and little by little is full of the velocity information that forwards packets to another receiving equipment at every turn and confirmed packet by another receiving equipment simultaneously.
Correspondingly, at step S21, the communication speed unit determines whether to carry out reconfiguring of this universal serial bus.Reconfigure if carried out, then the maximum transmission speed that unit 32 request series bus controllers 35 are provided with the transmission that can carry out, for example S400 are set in step S22 communication speed.Otherwise program enters S23, and communication speed unit 32 is read the transmission speed corresponding to a storage of this target receiving equipment from memory cell 34 herein.The speed of this storage determines before being that the data that can carry out this target receiving equipment with this speed send.Then speed is provided with unit 32 request series bus controllers 5 transmission speed that this is read is set.
Along with according to the transmission speed of the storage of target receiving equipment or according to the maximum transmission speed of this sending node transmission speed being set like this, process enters step S24, and this speed of sentencing setting sends an asynchronous packet.Step S24 is identical to S15 with the step S12 of Figure 17 to S27, and has therefore omitted the description to it.At step S25, confirm grouping if determined to receive one, then handle entering step S28.At step S28, ACK-detecting unit 33 sends a message and to communication speed unit 34 is set, and this message is that the request communication speed is provided with unit 34 storages (or storing again) and receives the record of receiving equipment of this asynchronous packet and its transmission speed, that is the speed of the grouping that, is identified.Like this, the speed of storage is the speed that data should continue to send to receiving equipment, and expression is for the maximum suitably speed that continues to send.This has finished the processing for the target receiving equipment, and asynchronous at this moment and/or isochronous data packet can send to the target receiving equipment with the speed of determining, maybe can repeat this program and be used for another target receiving equipment.
As mentioned above, by determining and be stored in the maximum transmission speed of the equipment of receiving terminal, the node of for example digital VTR 3 can send data to this equipment soon with the maximum transmission speed that can carry out the data transmission.Like this, the optimum speed that does not need to adopt the bus controlled entity to determine each node and send such information to each node when each bus reconfigures when taking place.
As previously mentioned, Figure 17 and 18 method are by sending an asynchronous packet and receiving the maximum transmission speed that each receiving equipment is set up in an affirmation.If continue to send synchrodata to this receiving equipment, then identical maximum speed information is preferred for synchronized transmission.
Be connected between two or more equipment (for example, MD group 5 and server 8 shown in Figure 19) and control under the situation of the synchronous data communication between those equipment at the node of for example digital VTR 3, said method of the present invention also is suitable for.For example, digital VTR can check and compare and can satisfy the maximum synchronous data communication speed that two equipment send.This can realize so that be determined to the maximum transmission speed of each equipment by digital VTR asynchronous transmission data to an equipment in each method as Figure 17.Then this numeral VTR sends expression should be provided with message to two equipment of what speed when sending to other equipment each equipment.
In the superincumbent description, used IEEE 1394 universal serial bus as an example, but the present invention can be applied to other interfaces with same characteristic features.This invention even be applicable to that permission carries out the agreement that data send by bus with any speed in a certain scope.In this case, high-end from this scope carried out the method for Figure 17 and 18 in substantially the same mode, and then gradually transmission speed reduced a predetermined quantity at step S15 and S17 in progressively mode, up to receiving the confirmation.
The present invention also comprises a storage medium, CD-ROM for example, and minidisk, floppy disk etc., this storage medium stores is by the treatment circuit of node, for example by the readable software program of the CPU 25 of digital VTR 3.This software program comprises the instruction of the treatment circuit of the aforesaid operations that is used to carry out Figure 17 and/or 18.
Though described the present invention above, be appreciated that these embodiment are exemplary and those skilled in the art can make change to the disclosed embodiments under the situation that does not break away from the spirit and scope of the present invention of determining as appended claims with reference to the preferred embodiments of the present invention.
Claims (24)
1. one kind sends the method for data by the transmitting apparatus that is connected to data/address bus, comprises step:
(a) send data by described transmitting apparatus with a known speed and be grouped on the described bus, described packet comprises the identification information of a target receiving device that connects described this bus;
(b) detect receiving device by described transmitting apparatus and whether sent a confirmation signal, this confirmation signal confirms the reception of the packet of described transmission;
(c), be provided with by described transmitting apparatus with the follow-up transmission speed that carries out the data transmission of the transmission speed of described forwarding step if detect a confirmation signal; With
(d) if do not detect confirmation signal, then with the transmission speed repeating step (a) that reduces and then repeating step (b) and (c).
2. method according to claim 1, wherein said known speed is initially set to the maximal rate that described transmitting apparatus can send data.
3. method according to claim 1, each in wherein said bus, described confirmation signal and the described known speed all meets IEEE 1394-1395 High Performance Serial Bus.
4. method according to claim 3 wherein, is lacking under the situation of bus manager, and described transmission speed is provided with in step (c).
5. method according to claim 1, also comprise: the transmission speed of described setting is stored in the memory of the described transmitting apparatus relevant with described receiving device, and reads as the follow-up described storage speed that sends data to the speed of described receiving device.
6. method according to claim 5, also comprise: and (d) one second receiving device repeating step (a) and (b), (c), and the described speed that is provided for described second receiving device stored in the described memory relevant with it, send and be read out with the follow-up data that is attached to described second receiving device.
7. it is that asynchronous data sends that method according to claim 5, wherein said follow-up data send.
8. it is that synchrodata sends that method according to claim 5, wherein said follow-up data send.
9. method according to claim 1, wherein said step (a) and (b), (c) and (d) execution after the bus reset operation of described bus.
10. method according to claim 5, wherein said step (a) and (b), (c) and (d) execution after the bus reset operation of described bus, wherein said memory is eliminated transmission speed information.
11. method according to claim 1, wherein said confirmation signal is a multiple bit digital signal.
12. method according to claim 1 wherein sends described packet immediately after by described transmitting apparatus described bus successfully being arbitrated.
13. method according to claim 1, wherein said transmitting apparatus are connected between two other equipment receiving described bus at least, and the data of controlling between described at least two other equipment send.
14. the messaging device that can be connected to bus, described messaging device comprises:
Data sending device is used for sending data to a receiving device that is connected to described bus through described bus;
Checkout gear is used to detect from described receiving device and sends, and confirms the affirmation signal of the reception of described transmission data; With
The transmission speed setting device is used for the state of the described confirmation signal that detects according at least one predetermined state of described bus with by described checkout gear, and the data transmission speed for described data sending device is set.
15. according to the described messaging device of claim 14, the described predetermined state of wherein said bus is the bus reset state.
16., also comprise the transmission speed storage device of the transmission speed that is used to store the setting relevant with described receiving device according to the described messaging device of claim 14.
17. described messaging device according to claim 16, wherein said data sending device is configured to, use multiple sending method to send data, and when any one method in the described multiple sending method of use sends data to described receiving device, use the data transmission speed of described setting.
18. according to the described messaging device of claim 17, wherein said multiple sending method comprises an asynchronous data sending method and a synchrodata sending method.
19. according to the described messaging device of claim 14, wherein said transmission speed setting device is provided with the data transmission speed according to the state of the described confirmation signal that is detected by described checkout gear.
20. according to the described messaging device of claim 14, wherein when described equipment was connected at least two described buses between other equipment, the data that described equipment is suitable for controlling between described at least two other equipment sent.
21. an information processing method that is used to be connected to the messaging device of bus, described messaging device sends data to a receiving device through described bus, and described information processing method comprises:
Send data to the described receiving device that is connected to described bus;
Detection sends from described receiving device, confirms the affirmation signal of the reception of described transmission data; With
According at least one particular state of described bus with to the detected state of described confirmation signal, be provided for the data transmission speed that follow-up data sends.
22. one kind by machine-readable storage medium, comprises really by the executable program command of described machine, so that carry out the method step that is used for by send data as the described machine of the transmitting apparatus that is connected to data/address bus, described method step comprises:
(a) send data by described transmitting apparatus with a known speed and be grouped on the described bus, described packet comprises the identification information of a target receiving device that connects described this bus;
(b) detect receiving device by described transmitting apparatus and whether sent a confirmation signal, this confirmation signal confirms the reception of the packet of described transmission;
(c), be provided with by described transmitting apparatus with the follow-up transmission speed that carries out the data transmission of the transmission speed of described forwarding step if detect a confirmation signal; With
(d) if do not detect confirmation signal, then with the transmission speed repeating step (a) that reduces and then repeating step (b) and (c).
23. according to the described storage medium of claim 22, wherein said known speed is initially set to the maximal rate that described transmitting apparatus can send data.
24. according to the described storage medium of claim 22, each in wherein said bus, described confirmation signal and the described known speed all meets IEEE 1394 High Performance Serial Bus.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN99109268A CN1241080A (en) | 1998-05-20 | 1999-05-20 | Method and apparatus for transmitting data over data bus at maximum speed |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP138033/98 | 1998-05-20 | ||
| CN99109268A CN1241080A (en) | 1998-05-20 | 1999-05-20 | Method and apparatus for transmitting data over data bus at maximum speed |
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| CN99109268A Pending CN1241080A (en) | 1998-05-20 | 1999-05-20 | Method and apparatus for transmitting data over data bus at maximum speed |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100377131C (en) * | 2001-12-11 | 2008-03-26 | 诺基亚有限公司 | Asynchronous serial data interface |
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1999
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100377131C (en) * | 2001-12-11 | 2008-03-26 | 诺基亚有限公司 | Asynchronous serial data interface |
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