JP3624767B2 - Data transfer control device, information storage medium, and electronic device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a data transfer control device, an information storage medium, and an electronic device, and in particular, a data transfer control device and an information storage medium for performing data transfer according to a standard such as IEEE 1394 between a plurality of nodes connected to a bus. And electronic devices.
[0002]
[Background Art and Problems to be Solved by the Invention]
In recent years, an interface standard called IEEE 1394 has been in the spotlight. This IEEE 1394 standardizes a high-speed serial bus interface that can be used for next-generation multimedia. According to the IEEE 1394, it is possible to handle data such as a moving image that requires real-time performance. In addition to computer peripheral devices such as printers, scanners, CD-RW drives, and hard disk drives, home appliances such as video cameras, VTRs, and TVs can be connected to the IEEE 1394 bus. For this reason, it is expected that digitalization of electronic devices can be dramatically accelerated.
[0003]
When an electronic device such as a printer is connected to such an IEEE 1394 bus, it has been found that the following problems occur.
[0004]
That is, in an ink jet printer or the like, if head cleaning is performed during printing, data flow stops for several minutes (up to about 5 minutes).
[0005]
On the other hand, an OS (Operating System) operating on an initiator (personal computer), for example, if data does not flow for 100 seconds, performs a reset process on the target (printer, data transfer control device) and then makes a new data transfer request. . When the reset process is performed, the internal information of the target is also cleared, so that the data transfer cannot be resumed after the head cleaning is completed.
[0006]
The present invention has been made in view of the technical problems as described above, and even when the data transfer with the upper layer device is interrupted for some reason, the data transfer is appropriately performed after the reason is resolved. An object is to provide a data transfer control device, an information storage medium, and an electronic device that can be resumed continuously.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a data transfer control device for data transfer between a plurality of nodes connected to a bus, and is based on a first data transfer request transferred from a counterpart node. Means for performing data transfer processing, and status transfer means for transferring the status of the data transfer processing to the counterpart node, wherein the status transfer means sends a status for the first data transfer request from the data transfer control device. The error status is transferred to the partner node when a timeout time T2 shorter than the timeout time T1, which is the time for the partner node to wait for the return, has elapsed.
[0008]
According to the present invention, the data transfer process is started by the first data transfer request from the counterpart node, and the status is transferred to the counterpart node. In the present invention, when a timeout time T2 shorter than the timeout time T1, which is a time for the partner node to wait for status return, elapses (when the timeout time is reached), a dummy error status is intentionally transferred to the partner node. Accordingly, the counterpart node waits again for the timeout time T1 to perform the reset process or the like. As a result, even if the data transfer with the upper layer device is interrupted for some reason (for example, head cleaning), the data transfer can be continued properly and resumed after the reason is resolved.
[0009]
Further, according to the present invention, when the data transfer with the upper layer device is not completed, the status transfer means transfers an error status to the partner node on condition that the timeout time T2 has elapsed. When the data transfer with the upper layer device is completed, the transfer completion status is transferred to the partner node. In this way, the counterpart node that has received the transfer completion status can appropriately continue and resume data transfer, for example, by making a second data transfer request having the same content as the first data transfer request. Become.
[0010]
According to the present invention, the upper layer device is a print processing device, and the status transfer means checks the error status on the condition that the timeout time T2 has passed in order to wait for the head cleaning time of the print processing device. It is characterized by forwarding to a node. In this way, even when the data transfer is interrupted for a long time to wait for the head cleaning time of the print processing device, the data transfer can be properly resumed after the head cleaning is completed.
[0011]
The present invention also provides restarting means for continuously restarting data transfer when a second data transfer request having the same content as the first data transfer request is transferred from the partner node that has received the error status. It is characterized by including. In this way, it is possible to prevent such a situation that data is double transferred, and it is possible to prevent malfunction of electronic equipment including the data transfer control device.
[0012]
In the present invention, it is desirable to perform data transfer conforming to the IEEE 1394 standard.
[0013]
The present invention is also an information storage medium including a program for controlling data transfer with any one of the data transfer control devices described above, wherein the first data transfer is performed before the timeout time T1 has elapsed. When the status for the request is not returned from the data transfer control device, a process for resetting the data transfer control device is performed, and when the error status is returned from the data transfer control device before the timeout time T1 elapses. And a program for making a second data transfer request having the same content as the first data transfer request to the data transfer control device. In this way, it is possible to prevent a situation in which erroneous data transfer restart processing is performed, and it is possible to prevent the occurrence of problems caused by interruption of data transfer.
[0014]
An electronic device according to the present invention includes any one of the data transfer control devices described above, a device that performs a given process on the data transfer control device and data received from a partner node via a bus, and a process. And a device for outputting or storing the received data. An electronic apparatus according to the present invention includes any one of the data transfer control devices described above, a device that performs a given process on the data transfer control device and data transmitted to a partner node via a bus, and a process. And a device for capturing data.
[0015]
According to the present invention, even when the data transfer between the electronic device and the data transfer control device is interrupted for some reason (for example, head cleaning), the data transfer can be properly resumed after the reason is resolved. . In addition, the data transfer speed can be increased, and the cost of the electronic device can be reduced and the processing speed of the electronic device can be increased.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
[0017]
1. IEEE 1394
First, IEEE 1394 will be briefly described.
[0018]
1.1 Overview
IEEE 1394 (IEEE 1394-1995, P1394.a) enables high-speed data transfer of 100 to 400 Mbps (800 to 3200 Mbps in P1394.b). It is also permitted to connect nodes with different transfer rates to the bus.
[0019]
Each node is connected in a tree shape, and a maximum of 63 nodes can be connected to one bus. If a bus bridge is used, it is possible to connect approximately 64,000 nodes.
[0020]
In IEEE 1394, asynchronous transfer and isochronous transfer are prepared as packet transfer methods. Asynchronous transfer is a transfer method suitable for data transfer that requires reliability, and isochronous transfer is a transfer method suitable for data transfer such as moving images and audio that requires real-time property.
[0021]
1.2 Layer structure
The layer structure (protocol structure) of IEEE1394 is shown in FIG.
[0022]
The IEEE 1394 protocol includes a transaction layer, a link layer, and a physical layer. Serial bus management monitors and controls the transaction layer, link layer, and physical layer, and provides various functions for node control and bus resource management.
[0023]
The transaction layer provides a transaction unit interface (service) to the upper layer, and performs transactions such as a read transaction, a write transaction, and a lock transaction through the interface provided by the lower link layer.
[0024]
Here, in the read transaction, data is transferred from the response node to the request node. On the other hand, in a write transaction, data is transferred from the request node to the response node. In the lock transaction, data is transferred from the request node to the response node, and the response node processes the data and returns it to the request node.
[0025]
The link layer provides addressing, data check, data framing for packet transmission / reception, cycle control for isochronous transfer, and the like.
[0026]
The physical layer provides conversion of logical symbols used by the link layer into electrical signals, bus arbitration, and a physical interface of the bus.
[0027]
1.3 SBP-2
As shown in FIG. 2, a protocol called SBP-2 (Serial Bus Protocol-2) has been proposed as an upper protocol including a part of the functions of the transaction layer of IEEE1394.
[0028]
Here, SBP-2 is proposed in order to make a SCSI command set available on the IEEE 1394 protocol. By using this SBP-2, the SCSI command set used in the existing SCSI standard electronic device can be minimally changed and used in the IEEE 1394 standard electronic device. Therefore, the design and development of electronic equipment can be facilitated. In addition, not only SCSI commands but also device-specific commands can be encapsulated and used, so the versatility is very high.
[0029]
As shown in FIG. 3, in SBP-2, a login process is first performed using a login ORB (Operation Request Block) created by an initiator (for example, a personal computer) (step T1). Next, initialization of the fetch agent is performed using the dummy ORB (step T2). Then, command processing is performed using the command block ORB (normal command ORB) (step T3), and finally logout processing is performed using the logout ORB (step T4).
[0030]
Here, in the command processing in step T3, as shown at A1 in FIG. 4, the initiator transfers the write request packet (issues a write request transaction) and rings the target doorbell register. Then, as shown in A2, the target transfers a read request packet, and the initiator returns a corresponding read response packet. As a result, the ORB (command block ORB) created by the initiator is fetched into the target data buffer. Then, the target analyzes the command included in the fetched ORB.
[0031]
If the command included in the ORB is a SCSI write command, the target transfers a read request packet to the initiator and the initiator returns a corresponding read response packet, as shown at A3. As a result, data stored in the data buffer of the initiator is transferred to the target. For example, when the target is a printer, the transferred data is printed by the printer engine.
[0032]
On the other hand, if the command included in the ORB is a SCSI read command, the target transfers a series of write request packets to the initiator, as indicated by B1 in FIG. Thereby, for example, when the target is a scanner, the scan data acquired by the scanner engine is transferred to the data buffer of the initiator.
[0033]
According to SBP-2, the target can transmit and receive data by transferring a request packet (issuing a transaction) when it is convenient for itself. Therefore, it is not necessary for the initiator and the target to move in synchronization, so that the data transfer efficiency can be improved.
[0034]
In addition to SBP-2, a protocol called FCP (Function Control Protocol) has been proposed as a higher-level protocol of IEEE 1394.
[0035]
When data is transferred between a target and an initiator, a page table may or may not exist in the data buffer (storage means) of the initiator (partner node) as shown in FIG.
[0036]
If a page table exists, the ORB created by the initiator includes the page table address and the number of elements, as shown in FIG. 6B. The address (read address, write address) of the transfer data is indirectly addressed using this page table.
[0037]
On the other hand, when the page table does not exist, as shown in FIG. 6C, the address and data length are included in the ORB, and the address of the transfer data is directly addressed.
[0038]
2. overall structure
Next, an example of the overall configuration of the data transfer control device of this embodiment will be described with reference to FIG. In the following, a case where the target for transferring data to and from the initiator is a printer will be described as an example, but the present invention is not limited to this.
[0039]
The data transfer control device 10 of the present embodiment includes a PHY device 12 (physical layer device), a link device 14 (link layer device), a CPU 16 (processor), a data buffer 18 (storage means), and firmware 20 (processing means). including. Note that the PHY device 12, the link device 14, the CPU 16, and the data buffer 18 are arbitrary components, and the data transfer control device 10 of the present embodiment does not need to include all these components.
[0040]
The PHY device 12 is a circuit for realizing the physical layer protocol of FIG. 1 by hardware, and has a function of converting a logical symbol used by the link device 14 into an electrical signal.
[0041]
The link device 14 is a circuit for realizing a part of the link layer protocol and the transaction layer protocol in FIG. 1 by hardware, and provides various services for packet transfer between nodes.
[0042]
The CPU 16 controls the entire apparatus and data transfer.
[0043]
The data buffer 18 is a buffer that temporarily stores transfer data (packets), and is configured by hardware such as SRAM, SDRAM, or DRAM. In the present embodiment, the data buffer 18 functions as a randomly accessible packet storage unit.
[0044]
The firmware 20 is a program including various processing routines (processing modules) that operate on the CPU 16, and a transaction layer protocol is realized by the firmware 20, the CPU 16 that is hardware, and the like.
[0045]
The device driver 102 included in the personal computer 100 serving as an initiator is a program including various processing routines for managing and controlling peripheral devices. This program is installed in the personal computer 100 using the information storage medium 110 (FD, CD-ROM, DVD, ROM).
[0046]
Here, the program of the device driver 102 may be downloaded from an information storage medium (hard disk, magnetic tape, etc.) of the host system via a network such as the Internet and installed in the personal computer 100. Use of the information storage medium possessed by such a host system is also included in the scope of the present invention.
[0047]
The firmware 20 (F / W) includes a communication unit 30 (COM), a management unit 40 (MNG), a print task unit 50 (PRT), and a fetch unit 60 (FCH).
[0048]
Here, the communication unit 30 is a processing module that functions as an interface with hardware such as the link device 14.
[0049]
The management unit 40 (management agent) is a processing module that manages login, reconnect, logout, reset, and the like. For example, when the initiator requests the target to log in, the management unit 40 first accepts the login request.
[0050]
The print task unit 50 is a processing module that performs data transfer processing with a printer engine, which is an application layer (upper layer) in the subsequent stage.
[0051]
The fetch unit 60 (fetch agent, command block agent) is a processing module for executing a command included in the command block ORB. Unlike the management unit 40 that can handle only a single request, the fetch unit 60 can also handle a linked list of ORBs fetched by a request from an initiator.
[0052]
The fetch unit 60 includes a data transfer processing unit 61, a status transfer unit 62, a command comparison unit 66, an address comparison unit 70, and a data transfer resume unit 72.
[0053]
Here, the data transfer processing unit 61 performs various processes (page table data) necessary for data transfer based on the ORB (command block ORB, which is a data transfer request in a broad sense) transferred from the initiator (partner node). Read, print data read, data transfer control, etc.).
[0054]
The status transfer unit 62 performs processing for transferring the status of data transfer processing (transfer completion status, error status, etc.) to the initiator.
[0055]
In this embodiment, the error status is transferred to the initiator on the condition that a timeout time T2 shorter than the timeout time T1, which is the time for the initiator to wait for the status return to the ORB, has elapsed.
[0056]
When the ORB is transferred again from the initiator that has received the error status, the command comparison unit 66 sends the contents of the retransmitted ORB (second data transfer request) and the ORB ( A process of comparing the content of the first data transfer request) is performed.
[0057]
When the ORB is transferred again from the initiator that has received the error status, the address comparing unit 70 receives the start address (second address, IEEE 1394 bus address) of the transfer data requested to be transferred by the retransmitted ORB. Then, a process of comparing the head address (first address) of the transfer data requested for transfer by the ORB being processed before is performed.
[0058]
The data transfer resuming unit 72 performs a process of continuously resuming data transfer when the contents of the ORB are the same and the head addresses are the same.
[0059]
From the viewpoint of process certainty, it is desirable to resume data transfer when the contents of the ORB are the same and the head addresses are the same. However, data transfer may be resumed only when the contents of the ORB match, or data transfer may be resumed only when the head addresses match. In this way, the processing burden can be reduced.
[0060]
3. Processing of this embodiment
Next, a processing example of this embodiment will be described.
[0061]
FIG. 8 is a flowchart illustrating an example of processing on the target side (firmware).
[0062]
When there is a print request from the initiator, the target reads the ORB from the data buffer of the initiator (step S1). If the page table exists, the page table is read from the data buffer of the initiator based on the page table address (see FIG. 6B) included in the ORB (step S2).
[0063]
Next, print data is read based on the read page table (step S3). Then, the read print data is DMA-transferred to the printer engine (print processing device) (step S4).
[0064]
Next, it is determined whether or not the DMA transfer of the print data to the printer engine is completed (step S5). If completed, the transfer completion status is transferred to the initiator (step S6).
[0065]
The above processing is repeated until all print data (all print data necessary for printing the printed matter) is transferred (step S7).
[0066]
In this embodiment, when it is determined in step S5 that the DMA transfer of the print data has not ended, it is determined whether or not the timeout time T2 on the target side has elapsed (whether or not the timeout time has been reached) ( Step S8). For example, when the data transfer to the printer engine is interrupted due to head cleaning or the like, the loop of step S5 and step S8 is repeated, and the process waits until the timeout time T2 elapses. In this case, the present embodiment is characterized in that the timeout time T2 is shorter than the timeout time T1 on the initiator side described later. In this embodiment, when this timeout time T2 elapses, a dummy error status is intentionally transferred to the target (step S9). Then, the state transitions to the idle state.
[0067]
FIG. 9 is a flowchart showing an example of processing on the initiator side (device driver).
[0068]
When a print job is generated from the application program, the initiator creates an ORB or page table for printing and writes it in the data buffer (step S20). Next, the target is instructed to read the created ORB (step S21; see A1 in FIG. 4).
[0069]
Next, it is determined whether or not the timeout time T1 on the initiator side has elapsed (step S22). This timeout time T1 is longer than the above-described timeout time T2 on the target side. If the timeout time has elapsed, a target reset process (abort task, abort task set, target reset, etc.) is performed, and then the ORB is recreated (step S23). Then, the target is instructed to read the re-created ORB (step S21).
[0070]
On the other hand, if it is determined in step S22 that the timeout time T1 has not elapsed, it is determined whether or not the status has been written (step S24). If the status is written before the timeout time T1 elapses, it is determined whether or not the status is an error status (step S25). For example, if the error status is intentionally written at T2 shorter than the timeout time T1 in step S9 in FIG. 8, it is determined that the error status is written in step S25.
[0071]
If it is determined in step S25 that the status is not an error status, it is determined whether or not all print data has been transferred (step S26). If not transferred, the process returns to step S20. End the print job.
[0072]
In this embodiment, when it is determined in step S25 that the status is an error status, the process proceeds to step S27, and it is determined whether a waiting time T (for example, 3 seconds) has elapsed. When the time elapses, the initiator re-creates the ORB and page table (step S28), and instructs the target to read the re-created ORB (step S21). In this case, the initiator (device driver) recreates the ORB so that the contents of the ORB, the start address of the print data, and the data length are the same before and after the occurrence of head cleaning. In this way, data transfer can be continued properly and resumed.
[0073]
4). Features of this embodiment
In an inkjet printer or the like, head cleaning may be performed during printing. When head cleaning is performed, data transfer is interrupted for several minutes as indicated by D1 in FIG. That is, even if the data transfer control device tries to transfer print data to the printer engine, the printer engine does not accept the print data, so the target data buffer becomes full and the data transfer is interrupted. Therefore, the target cannot return a transfer completion status to the initiator (see steps S5 and S6 in FIG. 8).
[0074]
On the other hand, as shown in D2 of FIG. 10, if the status does not return from the target before the timeout time T1 elapses, the initiator performs target reset processing (see steps S22 and S23 of FIG. 9). In this case, a gentle reset process such as an abort task or an abort task set is first performed, and if there is no response from the target, a strong reset process such as a target reset is performed.
[0075]
When the reset process is performed, internal information (the contents of the ORB, the start address of the transfer data, etc.) held by the target until then is also cleared. Therefore, the target cannot resume data transfer after the head cleaning is completed. As a result, the printer user had to discharge the paper with his / her hand and print again.
[0076]
Therefore, in this embodiment, as shown by E1 in FIG. 11, when a timeout time T2 shorter than the timeout time T1 on the initiator side has elapsed, a dummy error status is intentionally transferred to the initiator (FIG. 8). Steps S8 and S9). In this way, as indicated by E2 in FIG. 11, the initiator that has received the error status does not perform the reset process (in FIG. 9, it does not proceed to step S23, but proceeds to step S24). . Therefore, it is possible to prevent the internal information of the target from being cleared.
[0077]
During the head cleaning, the target continues to send a dummy error status to the initiator every time the timeout time T1 elapses. When the head cleaning is completed and the data transfer by ORB is completed, the target transfers a transfer completion status to the initiator (steps S5 and S6 in FIG. 8). Thereafter, data transfer is resumed from the continuation of the head cleaning occurrence time. In this case, in this embodiment, the target reset process by the initiator is not performed, and the target holds internal information at the time of occurrence of head cleaning, so that data transfer can be resumed from the continuation of the time of occurrence of head cleaning. Become.
[0078]
In order to properly resume the data transfer from the continuation of the head cleaning occurrence time, the following device is also required.
[0079]
For example, as shown in FIG. 12A, assume that head cleaning occurs when data is transferred to a position (address) indicated by C1. In this case, the initiator creates the ORB for printing again as shown in FIG. 12B, and instructs the target to restart the print data transfer from the beginning (steps S27 and S28 in FIG. 9). S21). For this reason, the data transfer is resumed from the position indicated by C2 in FIG. 12B, and only a part of the print data is sent twice. As a result, the problem of double printing as shown in FIG.
[0080]
In order to solve such a problem, in the present embodiment, a method as described below is adopted.
[0081]
For example, assume that head cleaning occurs during data transfer by the ORB indicated by F1 in FIG. Then, the target transfers an error status to the initiator as indicated by F2. Then, the initiator that has received this error status creates the ORB indicated by F3 again and transfers this ORB to the target (the target reads). In this case, in this embodiment, the contents of the ORB (first command packet) before head cleaning shown in F1 are compared with the contents of the ORB (second command packet) after head cleaning shown in F3. Further, the head address AD1 (first address) of the transfer data specified by the ORB before head cleaning is compared with the head address AD2 (second address) of the transfer data specified by the ORB after head cleaning.
[0082]
When it is determined that the contents of the ORB are the same and the head address is the same, the data transfer is continued and resumed as indicated by F4. That is, the data transfer is resumed from the continuation of the data transfer at the time when the head cleaning occurs (the data transfer is resumed from the data next to the data that has already been transferred at the time the head cleaning occurs).
[0083]
On the other hand, if the contents of the ORB are not the same or the head addresses are not the same, the ORB after the head cleaning shown in F3 is processed as a new ORB from the beginning.
[0084]
By doing so, the transfer data of the portion indicated by F5 in FIG. 13 is not double transferred unlike the case of FIG. Accordingly, erroneous printing as shown in FIG. 12C does not occur. In addition, since the double transfer can be avoided, the transfer time can be shortened.
[0085]
For example, as a method different from the present embodiment, a method may be considered in which data transfer is always resumed from the continuation of the head cleaning occurrence time, without comparing the ORB contents and the head address.
[0086]
However, according to this method, for example, even when the initiator cancels the print data transfer process after the head cleaning occurs and creates an ORB completely different from that before the head cleaning occurs, the data transfer is resumed from F4 in FIG. The trouble that it ends up occurs.
[0087]
On the other hand, in the present embodiment, when the ORB contents and the head address are the same before and after the head cleaning, the data transfer restarts from F4 in FIG. Since the processing is performed, the above-described problems do not occur.
[0088]
In the present embodiment, various types of information are compared when comparing the contents of the ORB. For example, as shown in FIG. 14, in this embodiment, the page table presence flag P included in the command block ORB, the data size, and the operation code (print command, read command, etc.) in the command block (command set) field are distinguished. Code) and data length. Further, when the ORB includes identification information (for example, a sequence number) for identifying the ORB, this identification information is also compared. By comparing such information, it is possible to reliably determine whether or not the ORBs before and after the occurrence of head cleaning are the same with a simple process.
[0089]
Note that the comparison of the head addresses AD1 and AD2 of the transfer data is specifically performed as follows. That is, when the page table is not used, it is compared whether or not the value of the data descriptor field of the ORB is the same. On the other hand, when the page table is used, it is compared whether or not the contents of the first segment of the page table are the same.
[0090]
5. Electronics
Next, an example of an electronic device including the data transfer control device of this embodiment will be described.
[0091]
For example, FIG. 15A shows an internal block diagram of a printer which is one of electronic devices, and FIG. 16A shows an external view thereof. A CPU (microcomputer) 510 controls the entire system. An operation unit 511 is used by a user to operate the printer. The ROM 516 stores control programs, fonts, and the like, and the RAM 518 functions as a work area for the CPU 510. A display panel 519 is for informing the user of the operating state of the printer.
[0092]
Print data sent from a partner node such as a personal computer via the PHY device 502 and the data transfer control device 500 is sent directly to the print processing unit (printer engine) 512 via the bus 504. The print data is subjected to a given process in the print processing unit 512, and is printed on paper by a print unit (device for outputting data) 514 including a print header and the like.
[0093]
FIG. 15B shows an internal block diagram of a scanner which is one of electronic devices, and FIG. 16B shows an external view thereof. The CPU 520 controls the entire system. The operation unit 521 is for the user to operate the scanner. The ROM 526 stores a control program and the like, and the RAM 528 functions as a work area for the CPU 520.
[0094]
An image of a document is read by an image reading unit (device for capturing data) 522 including a light source, a photoelectric converter, and the like, and the read image data is processed by an image processing unit (scanner engine) 524. Then, the processed image data is sent directly to the data transfer control device 500 via the bus 505. The data transfer control device 500 generates a packet by adding a header or the like to the image data, and transmits the packet to a counterpart node such as a personal computer via the PHY device 502.
[0095]
FIG. 15C shows an internal block diagram of a CD-RW drive which is one of electronic devices, and FIG. 16C shows an external view thereof. The CPU 530 controls the entire system. The operation unit 531 is for the user to operate the CD-RW. The ROM 536 stores control programs and the like, and the RAM 538 functions as a work area for the CPU 530.
[0096]
Data read from the CD-RW 532 by the reading & writing unit (device for capturing data or device for storing data) 533 including a laser, a motor, an optical system, etc. is input to the signal processing unit 534 and an error occurs. A given signal process such as a correction process is performed. Then, the data subjected to signal processing is directly sent to the data transfer control device 500 via the bus 506. The data transfer control device 500 generates a packet by adding a header or the like to this data, and transmits the packet to a counterpart node such as a personal computer via the PHY device 502.
[0097]
On the other hand, the data sent from the counterpart node via the PHY device 502 and the data transfer control device 500 is sent directly to the signal processing unit 534 via the bus 506. Then, given signal processing is performed on this data by the signal processing unit 534, and the data is stored in the CD-RW 532 by the reading & writing unit 533.
[0098]
15A, 15B, and 15C, in addition to the CPUs 510, 520, and 530, a CPU for data transfer control in the data transfer control device 500 may be provided separately.
[0099]
15A, 15B, and 15C, the RAM 501 (corresponding to the data buffer) is provided outside the data transfer control device 500, but the RAM 501 may be built in the data transfer control device 500. Good.
[0100]
If the data transfer control device of this embodiment is used in an electronic device, even if the data transfer is interrupted for reasons such as head cleaning, the data transfer can be properly resumed after the reason is resolved.
[0101]
Further, if the data transfer control device of this embodiment is used in an electronic device, high-speed data transfer can be performed. Therefore, when the user gives a printout instruction using a personal computer or the like, printing can be completed with a small time lag. In addition, the user can view the read image with a small time lag after the image capture instruction to the scanner. In addition, data can be read from the CD-RW and data can be written to the CD-RW at high speed.
[0102]
Further, by using the data transfer control device of this embodiment in an electronic device, the processing load of firmware operating on the CPU can be reduced, and an inexpensive CPU or a low-speed bus can be used. Furthermore, since the cost and scale of the data transfer control device can be reduced, the cost and scale of the electronic device can be reduced.
[0103]
In addition to the above, the electronic apparatus to which the data transfer control device of this embodiment can be applied includes, for example, various optical disk drives (CD-ROM, DVD), magneto-optical disk drives (MO), hard disk drives, TVs, VTRs, Various things, such as a video camera, an audio equipment, a telephone, a projector, a personal computer, an electronic notebook, a word processor, can be considered.
[0104]
In addition, this invention is not limited to this embodiment, A various deformation | transformation implementation is possible within the range of the summary of this invention.
[0105]
For example, the configuration of the data transfer control device of the present invention is particularly preferably the configuration shown in FIG. 7, but is not limited thereto.
[0106]
The command comparison method, the address comparison method, and the data transfer restart method are particularly preferably the methods described in this embodiment, but are not limited thereto.
[0107]
The present invention is particularly effective in solving the problem of interruption of data transfer during head cleaning, but is not limited to this. For example, the present invention is effective in solving various problems such as a problem of interruption of data transfer when a disk is formatted in a CD-RW drive.
[0108]
The present invention is particularly preferably applied to data transfer according to the IEEE 1394 standard, but is not limited to this. For example, the present invention can also be applied to data transfer in a standard based on the same idea as IEEE 1394 or a standard developed from IEEE 1394.
[Brief description of the drawings]
FIG. 1 is a diagram showing a layer structure of IEEE1394.
FIG. 2 is a diagram for explaining SBP-2.
FIG. 3 is a diagram for explaining an outline of SBP-2 data transfer processing;
FIG. 4 is a diagram for explaining command processing when data is transferred from an initiator to a target.
FIG. 5 is a diagram for explaining command processing when data is transferred from a target to an initiator;
6A, 6B, and 6C are diagrams for explaining a page table. FIG.
FIG. 7 is a diagram illustrating a configuration example of a data transfer control device of the present embodiment.
FIG. 8 is a flowchart showing an outline of processing on the target side (firmware).
FIG. 9 is a flowchart showing an overview of processing on the initiator side (device driver).
FIG. 10 is a diagram for explaining a problem of interruption of data transfer during head cleaning.
FIG. 11 is a diagram for describing a technique for transferring an error status to an initiator when a timeout time T2 shorter than the timeout time T1 on the initiator side has elapsed.
FIGS. 12A, 12B, and 12C are diagrams for explaining the problem of double printing. FIG.
FIG. 13 is a diagram for explaining a technique for continuing and restarting data transfer when the ORB contents and the start address of transfer data are the same before and after the occurrence of head cleaning.
FIG. 14 is a diagram for explaining comparison of contents of an ORB.
FIGS. 15A, 15B, and 15C are examples of internal block diagrams of various electronic devices.
16A, 16B, and 16C are examples of external views of various electronic devices.
[Explanation of symbols]
10 Data transfer control device
12 PHY devices
14 Link device
16 CPU
18 Data buffer
20 Firmware (F / W)
30 Communication Department (COM)
40 Management Department (MNG)
50 Print Task (PRT)
60 Fetch part (FCH)
61 Data transfer processor
62 Status transfer section
66 Command comparison part
70 Address comparison part
72 Data transfer resumption part
100 Personal computer
102 Device driver
104 Data buffer
110 Information storage medium

Claims (8)

A data transfer control device for transferring data between a plurality of nodes connected to a bus,
Data transfer processing means for performing data transfer processing based on the first data transfer request transferred from the counterpart node;
Status transfer means for transferring the status of the data transfer process to the partner node,
The status transfer means is
When a reset request is transmitted from the counterpart node when a counterpart node waits for the status for the first data transfer request to return from the data transfer control device, a timeout time T1 is exceeded,
When the first data transfer request is a DMA transfer request and the DMA transfer based on the DMA transfer request is completed within the timeout time T2 shorter than the timeout time T1, the transfer completion status is transferred to the partner node,
When the first data transfer request is a DMA transfer request and a timeout time T2 shorter than the timeout time T1 has elapsed during the DMA transfer processing based on the DMA transfer request, a dummy error status is sent to the partner node. Forward,
The data transfer processing means is
When the dummy error status is transferred to the counterpart node by the status transfer means , it waits for the DMA transfer request to be transferred again from the counterpart node,
If the status for the first data transfer request cannot be transferred to the counterpart node before the timeout time T1 elapses, the first data transfer is performed based on a reset request transmitted from the counterpart node. A data transfer control device characterized by clearing internal information about a request. In claim 1,
The status transfer means is
When the data transfer with the application layer device is not completed, the dummy error status is transferred to the partner node on condition that the timeout time T2 has passed, and A data transfer control device characterized by transferring a transfer completion status to a counterpart node when data transfer between them is completed. In claim 2,
The application layer device is a print processing device;
The status transfer means is
Data transfer characterized in that the dummy error status is transferred to the partner node when the timeout time T2 has elapsed in order to wait for at least the head cleaning time of the print processing device longer than the timeout time T1. Control device. In any one of Claims 1 thru | or 3,
Resuming means for continuing and resuming data transfer when a second data transfer request having the same contents as the first data transfer request is transferred from the counterpart node receiving the dummy error status; A data transfer control device. In any one of Claims 1 thru | or 4,
A data transfer control device that performs data transfer conforming to the IEEE 1394 standard. A computer-readable information storage medium storing a program for controlling data transfer with the data transfer control device according to any one of claims 1 to 5,
If the status for the first data transfer request is not returned from the data transfer control device before the time-out time T1 elapses, the data transfer control device is reset, and before the time-out time T1 elapses. When the dummy error status is returned from the data transfer control device, the computer is caused to function as a means for making a second data transfer request having the same content as the first data transfer request to the data transfer control device. An information storage medium comprising a program. A data transfer control device according to any one of claims 1 to 5,
A device that performs a given process on data received from a partner node via the data transfer control device and the bus; and
And an apparatus for outputting or storing processed data. A data transfer control device according to any one of claims 1 to 5,
An apparatus for performing a given process on the data transferred to the counterpart node via the data transfer control device and the bus;
An electronic apparatus comprising: a device for capturing data to be processed.

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