KR100294671B1 - apparatus and method for management in serial bus - Google Patents

Abstract

The serial bus management apparatus and method stores the data type and band whistle value of the channel transmitted to the isochronous resource manager and transfers the used channel and band whistle when data is necessary for real time transmission. Receives real-time data and transmits it to a serial bus management device equipped with an IRM (Isochronous Resource Manager) consisting of BAR (Bandwidth_Available Register) and CAR (Channel_Available Register). The IRM comprises a first register for setting whether to assign an assigned channel and a band whistle, and a second register for storing information on a corresponding channel if a value of the first register is transferable. There is.

Description

Serial bus management device and method {apparatus and method for management in serial bus}

The present invention relates to a bus system, and more particularly, to a serial bus management apparatus and method.

The rapid changes in today's digital audio / video have increased the demand for high-speed digital interfaces between consumer electronic devices in the home, This demand has led to the use of the IEEE 1394 serial bus.

The high-speed digital interface includes a set-top box using an MPEG-2 transport stream, an interface between a digital TV, a DVCR, and a digital camcorder.

Although the IEEE 1394 serial bus was originally designed as an interface to replace a small computer system interface (SCSI) for connecting a PC and a peripheral device, the IEEE 1394 serial bus is not only a high-speed serial bus but also hot plugging and flexible. It is expected as a next-generation interface for connecting PCs and information appliances because it has many features such as topology, connection of many digital audio / video devices, and isochronous data communication mode suitable for real-time data transmission.

The topology of the IEEE 1394 serial bus may connect each device in a tree structure without a loop, and connect up to 63 devices to one local bus.

Hereinafter, a serial bus management apparatus according to the prior art will be described with reference to the accompanying drawings.

1 is a diagram illustrating a topology of a 1394 serial bus according to the prior art, in which a digital TV 1, a PC 2, a CDROM 3, a digital camera 4, and a digital camcoder 5 are shown. ), DVCR (6), DVD RAM (7), and Printer (8) are connected by a 1394 serial bus so as not to form a loop.

FIG. 2 is a diagram illustrating a relationship between 1394 serial bus protocol layers according to the prior art, and includes serial bus management (hereinafter, referred to as SBM) 11, a physical layer 12, and FIG. Link layer 13, A / V CIP layers 14, Application layer, Transaction layer 16, Plug control register (Plug Control Register) 17, Connection Management Protocol section 18, Function Control Protocol section 19, and audio / video control command and transaction set (AV / C) Command and Transaction Set) and SBP-2 (20).

3A and 3B illustrate data formats of a BAR and a CAR in the serial bus management of FIG. 2.

First, as shown in FIG. 1, the physical connection between the devices is connected by a 1394 serial bus cable for transmitting data in both directions, and the devices have one or more 1394 serial bus cable connection ports.

The configuration of the network is then automatically determined at bus initialization, and devices with multiple cable ports act as signal repeaters to create a local bus.

Each device on the 1394 serial bus is configured for terminators, transceivers, arbitration, packet formatting, and data transfer control for each port. It is composed of logic and isochronous data through channels and bandwidth allocated from asynchronous data and SBM's Isochronous Resource Manager (hereinafter abbreviated as IRM). ).

The SBM is a node controller for isochronous communication and associative communication, an IRM for isochronous communication, a bus topology, a bus speed, a power management ( It is composed of a bus manager for performing power management.

The isochronous data is transmitted in an isochronous packet structure as real time data, and a common isochronous packet application interface layer for processing such isochronous packets is provided. The relationship between the protocol layers of the 1394 serial bus having a common isochronous packet application interface layer is shown in FIG.

The protocol is to send a series of source packets from an application of one device to an application of another device.

In order to transmit the isochronous packet, one IRM is required on a bus, which is determined by a self-ID packet transmitted by each node when the bus is reset.

That is, the self-ID packet includes link_active and Contender bits to indicate whether a node is an IRM-capable node, or a node having the largest physical ID (node ID) when there are multiple IRM-capable nodes. Becomes IRM.

These self-ID packets are transmitted to all nodes on the 1394 serial bus so that all nodes on the 1394 serial bus can know the node ID of the IRM.

The isochronous communication is performed in synchronization with a cycle start packet transmitted by one cycle master existing on the bus at predetermined intervals (8 ms and 125 µsec).

When the transmitting node of the isochronous communication receives a cycle start packet, it waits for an isochronous gap and starts arbitration, and if it acquires ownership of the bus, it starts isochronous packet transmission. do.

At this time, if there is a node that wants to transmit an isochronous packet, it waits for the isochronous gap continuously, then starts abitation and transmits an isochronous packet.

The cycle packet transmitted by the cycle master is transmitted first because the cycle packet has the highest priority in the arbitration. As a result, the root becomes a cycle master.

On the other hand, the IRM of the 1394 serial bus provides three types of registers: a bandwidth_available register (BAR), a channel_available register (CAR), and a bus_manager_id register (BMR).

As shown in FIG. 3A, the BAR is a 32-bit register indicating the size of a band whiskey that can be used in the isochronous communication. The node to initiate the isochronous communication is to use the value of the BAR. After subtracting and setting the band whistle, it is added again when the isochronous communication is completed.

As shown in FIG. 3B, the CAR is a 64-bit register indicating the allocation state of the channel used in the isochronous communication. When the value of the bit is "0", the CAR indicates that the channel is currently in use. If the value of the corresponding bit is "1", it indicates that the channel is not used.

Accordingly, the node to start isochronous communication confirms that the value of the corresponding bit of the channel to be used is "1", sets the bit to "0", and then starts communication using the corresponding channel.

The BMR is a 32-bit register used to determine the bus manager. The initial value 3Fh indicates that the bus manager does not exist, and the node intending to become the bus manager has the register value of 3Fh within a predetermined time after the bus reset. After confirming that, by setting its own node ID performs the role of the bus manager.

In this case, a Compare_Swap Lock Transaction is used to change the values of the registers as described above.

Therefore, the node which wants to transmit the isochronous packet sets the band whiskey and channel used for the transmission to the BAR and CAR of the IRM and then starts the transmission.

However, in the serial bus management apparatus and method according to the prior art, since the channel and the band whiskey are limited, if there are no remaining channels and band whistle when multiple nodes are connected, data such as DTV signal does not necessarily transmit data requiring real time transmission. There is a problem.

Accordingly, the present invention has been made to solve the above problems, and the data is a data that must be transmitted in real time after storing the data type and the band whistle value of the channel transmitted to the isochronous resource manager. The purpose of the present invention is to provide a serial bus management device that transmits real-time data by transferring the channel and band whistle being used.

Another object of the present invention is to provide a serial bus management method corresponding to the above apparatus.

1 is a diagram illustrating a topology of a 1394 serial bus according to the prior art.

2 illustrates a relationship between 1394 serial bus protocol layers according to the related art.

3A and 3B illustrate data formats of BAR and CAR in the serial bus management of FIG.

4A and 4B illustrate data formats of SAR and RHR of IRM in a serial bus management apparatus according to the present invention.

5 is a flowchart illustrating an operation state for transmitting isochronous packet data by allocating a channel and a band whistle from an isochronous resource manager according to the serial bus management method according to the present invention.

FIG. 6 is a flowchart illustrating an operation state for returning the allocated channel and band whiskey in FIG.

Features of the serial bus management apparatus according to the present invention for achieving the above object, IRM (Isochronous Resource) consisting of BAR (Bandwidth_Available Register), CAR (Channel_Available Register) for allocating channels and band whistle in isochronous communication In the serial bus management device having a manager), the IRM stores a first register for setting whether to assign the assigned channel and the band whistle, and information on the corresponding channel if the value of the first register is transferable. It further comprises a second register for.

Another feature of the serial bus management apparatus according to the present invention for achieving the above object is that the information stored in the second register is transferable channel information and bandwise value, the node number and transfer currently using the corresponding channel It's called a node number.

Another feature of the serial bus management method according to the present invention for achieving the above object is, in the serial bus management method of transmitting isochronous packet data by assigning a channel and a band whistle, wherein any node is iso Searching whether all of the isochronous resources that are already allocated by other nodes are being used when attempting to transmit the Kronus packet data; and if the search result is used, isochronization to be transmitted. According to which device the packet data is communication between the channel and the band whiskey already occupied temporarily and the isochronous packet data is transmitted.

Another feature of the serial bus management apparatus according to the present invention for achieving the above object is that the transmission step is for transmission between devices that can be temporarily transferred the channel and band whisked occupied by the arbitrary node. Accordingly, the present invention has a table that prescribes the transfer relationship of isochronous packet data in a transferable and non-transferable state.

Another feature of the serial bus management apparatus according to the present invention for achieving the above object, the transmitting step is to temporarily transfer the channel and the band whiskey in use by another node to transmit the isochronous packet data. After the receiving node finishes transmitting the isochronous packet data to be transmitted, the method further comprises returning the channel and the bandwhis to the node that owned the original channel and the bandwiss.

Hereinafter, a preferred embodiment of a serial bus management apparatus and method according to the present invention will be described with reference to the accompanying drawings.

4A and 4B illustrate data formats of SAR and RHR of an IRM in a serial bus management apparatus according to the present invention.

FIG. 4A is a data format of SAR of an IRM in a serial bus management apparatus, and is composed of shared_available_hi of 0 to 31 bits and shared_available_lo of 31 to 63 bits, and FIG. 4B is a data format of RHR of IRM in a serial bus management apparatus. Is reserved, 6 bits Original_Node_ID, 6 bits Node_ID, 13 bits used_bandwidth, and Channel Number.

The information stored in the RHR of the IRM is transferable channel information and band whistle value, node number currently using the channel and transfered node number.

The SAR illustrated in FIG. 4A has an initial value of "1", a dirty state bit of "1", and a shared state bit of "0". The reserved 7 bits of RHR and 13 bits of used_bandwidth, respectively, are set. Is set to an initial value "zeros", 6-bits Original_Node_ID, 6-bits Node_ID are each set to an initial value "ones", and Channel Number is set to an initial value "0".

The SAR is a first register and the RHR is a second register.

FIG. 5 is a flowchart illustrating an operation state for transmitting isochronous packet data by receiving a channel and a band whiskey from an isochronous resource manager according to the serial bus management method according to the present invention, and FIG. This is a flowchart showing the operation status to return the received channel and band whiskey.

The operation of the serial bus management apparatus and method according to the present invention will be described in detail with reference to the accompanying drawings.

The data format of the BAR and CAR to be assigned the channel and the band whistle in the isochronous communication between the components of the bus system connected to the 1394 serial bus to which the present invention is applied, the relationship between the 1394 serial bus protocol layers of the device 1 and 3, the description thereof will be omitted.

First, the serial bus management apparatus according to the present invention requests allocation of a channel and a bandwidth to an isochronous resource manager when an arbitrary node tries to transmit isochronous packet data. (S1, S2).

Then, the isochronous resource manager searches for the internal BAR and CAR as shown in FIGS. 3A and 3B according to the request, and searches whether the requested channel and the band whiskey are used. Any node that attempts to transmit the isochronous packet changes the values of CAR, BAR, SAR, and RHR of the IRM, and receives the channel and the band whistle to start the transmission of the isochronous packet data (S4).

That is, any node that attempts to transmit the isochronous packet data sets the bit of the channel to be allocated to the CAR of the IRM to "0" to inform the outside that the channel is in use.

In addition, any node that intends to transmit the isochronous packet data is set by subtracting the size of the bandwhile to use from the BAR.

In addition, as shown in FIG. 4A, the assigned channel bits are set in the SAR to a shared state (bit = 0) or a dirty state (bit = 1), which are transferable and non-transferable according to Table 1 above. As shown in Fig. 4B, an appropriate value is set in the register field of the corresponding channel (the allocated channel) of the RHR.

That is, the size of the transferred bandwidth is set in the used_bandwidth field, the value of the Node_ID field is copied to the Original_Node_ID (O_Node_ID) field, its node ID is set in the Node_ID field, and the transferred number is set in the channel number. Set the channel number.

Table 1 shows whether the channel and the band whistle transfer in real time isochronous packet data transmission.

DTV DVCR Digital camcoder Hard disk DVD RAM Digital Camera CDROM · · · DTV X One X One One X X DVCR One 0 X 0 0 X X Digital camcoder One 0 X 0 0 X X Hard disk One 0 X 0 0 X X DVD RAM One 0 X 0 0 X X Digital Camera One 0 X 0 0 X X CDROM One 0 X 0 0 X X · · ·

In this case, the real time isochronous packet data transmission between devices is set to "1", which is necessary for real time transmission, and "0", which is not necessary and can transfer the assigned channel and band whistle.

"X" indicates that the transmission is invalid.

At this time, since both Node_ID and O_Node_ID have the initial value "11111", the value of O_Node_ID before and after copying is the same.

In this state, after appropriately setting the values of all registers, the arbitrary node starts to transmit isochronous packet data.

In addition, if the search result in the S3 is not available, that is, if the channel to be used is already used by another node, or if no channel is available and the bandwidth of the size to be used is not available, the IRM is described above. Referring to Table 1, it is searched whether the isochronous packet transmission of the arbitrary node is a transmission capable of requesting the transfer of the channel and the bandwidth used.

As a result of the search, if it is an isochronous transmission capable of requesting the transfer of the channel and the band whistle in use, the IRM searches whether there is at least one shared bit in the SAR (Shared_Available Register). It is searched whether there is a node owning more than the size of the bandwidth to be used by the arbitrary node among the nodes owning the channel and the band whis (S6 and S7).

That is, if there are channels having a shared state in which the bit value of the SAR is "0", the IRM searches for channels having more than the bandwidth required for isochronous transmission based on the RHR values of the channels.

If there is a node owning more than the size of the bandwidth to be used by the node as a result of the search, the channel and the band to the node owning the smallest band of the nodes owning more than the size of the bandwidth to be used. Request transfer of whistle (S8).

Then, the node receiving the channel and the band whiskey sets the corresponding bit of the CAR of the IRM to "1", changes the channel to be available to other nodes, and adds the band whistle as much as the size allocated to the BAR. Release the channel and band whistle (S9).

In this state, if the isochronous packet data transmission of another node may interrupt to use the channel and the band whiskey, the original channel may be maintained by maintaining the bit value of the corresponding channel of the SAR in a shared state of "0". Only the node having the isochronous packet data transmission requesting the transfer of the bandwidth and the bandwidth can transfer the channel and the bandwidth.

As described above, when the channel and the band whiskey is released, the node requesting the transfer of the channel and the band whiskey sets "0" to the corresponding channel bit of the CAR to inform the outside that the channel is owned and to use the BAR. Add the size of the band whistle.

And set to "1" to change the corresponding channel bit of SAR to Dirty state.

As a result, the once-transmitted channel and bandwhile are not transferred again by another isochronous transmission.

In addition, the value of the register field corresponding to the corresponding channel of the RHR is changed.

That is, it sets the bandwidth of the used_bandwidth field by the amount added to the BAR, copies the value of the Node_ID field into the O_Node field, and uses it to inform the node that owned the original channel and the bandwist to continue the previous transmission. In the Node_ID field, the ID of the node that has received the channel and the band whiskey is set.

After the values of all registers are set properly, transmission of the isochronous packet data is started.

Meanwhile, whether an isochronous packet data transmission is completed or an node is currently in use by another node while the isochronous packet data transmission is performed by an arbitrary node having ownership of a channel and a band whiskey. It is searched whether the transfer of the channel and the band whistle being requested is requested (ST1, ST2).

If the search result is not complete, the node receiving the transfer request of the channel and the band whiskey sets the corresponding bit of the CAR of the IRM to "1" and the size allocated to the BAR. The channel and band whiss are released by adding the band whistle (ST3, ST4).

If the transmission of the isochronous packet data is completed, it is determined whether the value of the O_Node_ID field of the RHR of the IRM is “11111” b. If the value is not “11111” b, the corresponding bit of the CAR is set to “1”, Bandwidths of the allocated size are added (ST5 and ST6).

In addition, the corresponding bit of the SAR is set to “1”, which is a dirty state, and the node having the value of the O_Node_ID field of the RHR is informed to continue the previous transmission and all the fields are initialized.

If the result of the search is "11111" b, the corresponding bit of the CAR is set to "1", and the band whistle equal to the size allocated to the BAR is added (ST7).

In addition, the corresponding bit of the SAR is set to “1”, which is a dirty state, and the fields of the RHR are initialized.

As the channel and the band whis are released, another node is able to transmit isochronous packet data using the released isochronous resource (ST8).

That is, when the transmission of the isochronous packet data is completed, the node sets the corresponding channel bit of the CAR to "1" if the value of the O_Node_ID field of the RHR of the IRM is "11", and the band whistle of the size allocated to the BAR. Add.

In addition, by setting the corresponding channel bit of the SAR to "1" in the dirty state, and initializing the field value of the RHR to release the channel and the band whiskey, the isochronous resource is released using the isochronous resource released by another node. Makes it possible to transmit the nut packet data.

If the value of the O_Node_ID field of the RHR is not "11111", set the corresponding channel bit of the CAR to "1" and instruct the node having the value of the O_Node_ID field of the RHR to continue the previous transmission, and then initialize the values of all fields. do.

By releasing the channel and the band whiskey, the node that originally owned the channel and the band whiskey can continue to transmit the previous isochronous packet data using the released isochronous resource.

On the other hand, the node requesting the transfer of the channel and the band whiskey as a result of the search in ST2 sets the corresponding bit of the CAR of the IRM to "1" so that another node can use the channel and the band is allocated to the BAR. Add channels to release channels and bands.

In the above state, if isochronous packet data transmission of another node may intervene to use the channel and the band whistle, the bit value of the corresponding channel of the SAR maintains the value of "0" of the shared channel and the band whiskey. Only the node having the transmission of isochronous packet data that has requested the transfer of the channel and the band whistle should be transferred.

By releasing the channel and the band whistle, a node requesting the transfer of the channel and the band whistle can transmit isochronous packet data using the released isochronous resource.

As described above, the apparatus and method for managing a serial bus according to the present invention is data that requires real-time transmission after storing data type and band whistle value of a channel transmitted to an isochronous resource manager. In this case, it is possible to transmit isochronous packet data that requires real-time transmission by transmitting the channel and the band whiskey being used to transmit real-time data.

Claims (5)

Controller for isochronous communication and earthing communication, Serial isochronous resource manager (IRM) including a bandwidth_available register (BAR) and a channel_available register (CAR) for allocating a band whistle and a channel for isochronous communication, and a bus manager for performing bus power management In the management apparatus, The IRM comprises one register for storing the data type and the band whistle value of the channel currently being used; If the channel and the band whistle stored in the first register is transferable when the transfer request of the channel and the band whistle currently being used, further comprising a second register for storing information about the transferred channel Serial bus management device. The method of claim 1, The information stored in the second register is Assignable channel information and bandwhile value; Serial bus management device, characterized in that the node number currently using the channel and the transferred node number. In the serial bus management method for transmitting isochronous packet data by receiving a channel and band whistle, Retrieving whether an isochronous resource that is already being allocated by other nodes is used when any node is to transmit isochronous packet data; If all of the search results are used, the step of transmitting the isochronous packet data by temporarily transferring the already occupied channel and bandwhis depending on which device the isochronous packet data to be transmitted is communication between the devices. Serial bus management device. The method of claim 3, wherein The transmitting step, According to a table previously defined in a transferable and non-transferable state of isochronous packet data according to transmission between devices capable of temporarily transferring the channel and band whistle occupied by the arbitrary node. Serial bus management method characterized in that the transfer. The method of claim 3, wherein The transmitting step After the node that has been temporarily transferred the channel and bandwhis used by another node to transmit the isochronous packet data has finished transmitting the isochronous packet data to be transmitted, it has ownership of the original channel and bandwhis And returning a channel and a band whistle to the node that was present.