JP2010039975A - Usb host system, data transfer method and video and sound processing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accelerate a data transfer speed with a USB device. <P>SOLUTION: A USB host system 100 is provided with a temporary transfer interrupt processing part 102. When data transfer is performed between a USB host controller 103 and the USB device 108, the temporary transfer interrupt processing part 102 temporarily interrupts the data transfer between the USB host controller 103 and the USB device 108, waits until prescribed processing to data stored in a USB host transfer memory 105 is completed to make the USB host transfer memory 105 usable, and restarts the data transfer between the USB host controller 103 and the USB device 108 each time transfer data of a prescribed size of the memory size of the USB host transfer memory 105 or below is transferred between the USB host controller 103 and the USB device 108. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a USB host system equipped with a USB host, such as a video / audio device (hereinafter referred to as AV device), a data transfer method between the USB host system and the USB device, and the USB host system. The present invention relates to a video / audio processing system using the.

  There is a standard "Universal Serial Bus" (hereinafter referred to as USB) as one of the external buses connecting personal computers (hereinafter referred to as PCs) and their peripheral devices. The USB host function is provided on the PC side and the peripheral devices side. This is realized by installing a USB device function.

As means for improving the transfer speed of data transfer between a PC and a peripheral device, there are a method for improving the transfer capability on the USB host side and a method for improving the transfer capability on the USB device side. Is incorporated in a system equipped with a high-speed CPU and a large-capacity memory called a PC, and therefore does not focus on efforts to improve speed. Rather, efforts have been made to improve the transfer speed of USB devices incorporated in a system equipped with a powerless CPU and a small amount of memory (see, for example, Patent Document 1).
JP 2001-337913 A

  However, in recent years, a USB host has been incorporated into an AV system other than a PC, such as an AV component or a digital video recorder, and the use of connecting the AV system and a USB storage device has begun to spread. For data transfer between the AV system and the USB storage device, a standard generally referred to as a USB mass storage class is used. The standard includes a data request phase, a data transfer phase, and a status confirmation phase.

  The AV system has a lower processing capacity of the CPU and a smaller amount of installed memory than the PC. Therefore, the transfer size at which data can be requested at one time is limited by the usable memory size. For example, if a memory of 100 Kbytes can be used for transfer, the data request phase in the USB mass storage class requires a transfer of 100 Kbytes or less. In other words, even if you want to transfer data that is larger than the available memory size, you need to request transfer for each available memory size, and for each request, the data request phase and status of the USB mass storage class Since the confirmation phase is necessary, there is a problem that the transfer speed becomes slow. That is, when the memory size that can be used by the USB host controller is small, a data request phase and a status confirmation phase are required for each transfer of the memory size, and the transfer speed becomes slow.

  The present invention solves the above-mentioned problem, a USB host system capable of high-speed USB transfer, a data transfer method for performing high-speed transfer between a USB host system and a USB device, and high-speed USB transfer An object is to provide a video / audio processing system.

  In order to solve the above problems, a USB host system according to the present invention is accessed by a central processing unit, a USB host controller having a USB host function, and the central processing unit and the USB host controller. Main memory including a USB host transfer memory that can be used for temporary storage of transfer data transferred between a USB device and a USB device connected to the USB host controller via a USB bus, and a USB host controller and a USB device When data transfer is performed between the USB host controller and the USB device, the transfer between the USB host controller and the USB device is performed between the USB host controller and the USB device every time transfer data of a predetermined size less than the memory size of the transfer memory is executed. The data transfer of And a and temporary transfer suspension processing unit to resume the data transfer between the USB host controller and the USB device waiting to transfer memory and predetermined processing is completed becomes available for storing data in the directory.

  When a USB host system and a USB device are connected and data transfer is performed via USB, the data to be transferred needs to pass through a transfer memory. Therefore, if you want to transfer more than the size of the available transfer memory, request the USB device for the data size you want to transfer, and set the transfer settings for the available transfer memory size to the USB host controller. And perform the transfer. When the data transfer of the size set in the USB host controller is completed, the upper software such as an application processes the transferred data. The USB transfer waits until the data processing by the upper software is completed and the transfer memory becomes usable. When the transfer memory becomes usable, transfer settings corresponding to the size of the usable transfer memory among the remaining data to be transferred are set to the USB host controller, and USB data transfer is performed. The above processing is repeatedly executed, and when all data to be transferred is completed, a status confirmation request is made to the USB device. According to the above method, even when data transfer larger than the size of the usable transfer memory is performed, the data request and status confirmation performed for the USB device only need to be performed once, and the transfer speed can be improved. That is, in the data request phase, a transfer request larger than the memory size usable by the USB host controller is made to the USB device, and a transfer request for each usable memory size is set to the USB host controller. Transfer of the data request phase and status confirmation phase required for each transfer of the size can be reduced, and the transfer speed is improved.

  The intermittent USB transfer process control is realized by a temporary transfer interruption processing unit.

  In the above USB host system of the present invention, the USB host controller conforms to the EHCI (enhanced host controller interface) standard, the OHCI (open host controller interface) standard, and the UHCI (universal host controller interface) standard. It is preferable to comply with either.

  In the above configuration, it is preferable that a command used for USB transfer conforms to the USB mass storage standard.

  The data transfer method of the present invention is a data transfer method for transferring data between a USB host system and a USB device, and the USB host system requests the USB device to transfer data larger than the memory size of the transfer memory. A second step in which the USB device makes a transfer setting to the USB host controller that is less than or equal to the memory size of the transfer memory, and the USB device has data for the transfer size set in the USB host controller. A third step of performing transfer, and a fourth step of determining whether or not the transfer of the data requested to be transferred in the first step has been completed. In the fourth step, the transfer of data is completed If it is determined that it has not been performed, the second to fourth steps are repeated.

  According to this method, even when data transfer exceeding the size of the usable transfer memory is performed, the data request and status confirmation performed for the USB device only need to be performed once, and the transfer speed can be improved. .

  In the above data transfer method, when the USB device is compatible with the USB mass storage standard, a data transfer request made by the USB device before the first step in the transfer between the USB device and the USB host system. Is preferably performed by a CBW (Command Block Wrapper).

  The video / audio processing system of the present invention includes a USB host system and a USB device that is connected to the USB host system and inputs / outputs video / audio signals to / from the USB host system. The USB host system is accessed from a central processing unit, a USB host controller having a USB host function, a central processing unit and a USB host controller, and the USB host controller and the USB host controller are connected via a USB bus. A main memory including a USB host transfer memory that can be used for temporary storage of transfer data consisting of video and audio signals transferred to and from the connected USB device, and a video and audio signal stored in the USB host transfer memory. When transferring data between the USB host controller and the USB device, and when the data is transferred between the USB host controller and the USB device, a transfer data having a predetermined size less than the memory size of the transfer memory is decoded. USB every time a transfer is executed The USB host controller and the USB device wait for the transfer memory to be usable after the predetermined processing by the decoding unit for the stored data in the transfer memory is completed after the data transfer between the controller and the USB device is temporarily suspended And a temporary transfer interruption processing unit for resuming data transfer to and from.

  According to this configuration, the same effects as those of the USB host system can be obtained in transmitting the audio / video signal.

  According to the present invention, in the transfer between the USB device and the USB host system, the data transfer request process and the status confirmation process are reduced, so that the transfer speed in the USB transfer can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Embodiment 1]
FIG. 1 is a block diagram showing a schematic configuration of the USB host system according to the first embodiment of the present invention. In FIG. 1, 100 is a USB host system, 101 is a CPU (central processing unit), 102 is a temporary transfer interruption processing block for performing temporary transfer interruption processing, 103 is a USB host controller having a USB host function, and 104 is central processing arithmetic. Main memory accessed from the device and the USB host controller, 105 a USB host transfer memory for temporarily storing data that the USB host controller 103 transfers to and from the USB device in the main memory 104, and 106 a USB A data processing block for processing the data transferred by, 107 is a USB bus, and 108 is a USB device connected to the USB host controller 103 via the USB bus 107.

  The temporary transfer interruption processing block 102 described above does not exceed the memory size of the USB host transfer memory 105 between the USB host controller 103 and the USB device 108 when transferring data between the USB host controller 103 and the USB device 108. Each time transfer of transfer data of a predetermined size is executed, the data transfer between the USB host controller 103 and the USB device 108 is temporarily interrupted, and the predetermined processing for the stored data in the USB host transfer memory 105 is completed. It has a function of resuming data transfer between the USB host controller 103 and the USB device 108 after waiting for the USB host transfer memory 105 to become usable.

  This temporary transfer interruption processing block 102 is implemented as software processing of the CPU 401, for example. In addition to this, a configuration in which dedicated hardware is constructed and the dedicated hardware directly controls the USB host controller 403, such as a hardware sequencer, is also conceivable.

  The above USB host controller conforms to any of the EHCI (Enhanced Host Controller Interface) standard, OHCI (Open Host Controller Interface) standard, and UHCI (Universal Host Controller Interface) standard. Yes. Commands used for USB transfer comply with the USB mass storage standard.

  FIG. 2 is a flowchart showing the operation of the first embodiment of the present invention. In the first embodiment, the USB host controller 103 is used, and the USB host transfer memory 105, which is a memory area that the USB host controller 103 of the main memory 104 can use to transfer data stored in the USB device 108. The case of transferring to will be described. In the description, the data size read by the data processing block 106 from the USB device 108 is assumed to be 1024 Kbytes, and the size of the USB host transfer memory 105 is assumed to be 256 Kbytes.

  Hereinafter, the flowchart of FIG. 2 will be described. When a data reading request of 1024 Kbytes to the USB device 108 is generated from the data processing block 106 (step S201), the temporary transfer interruption processing block (software operating on the CPU) 102 has a read request size for the USB device 108. A 1024 KB data read request is sent (step S202).

  Next, the USB host controller 103 is set to read data of 256 Kbytes, which is the size of the USB host transfer memory 105, from the USB device 108 to the USB host transfer memory 105. Transfer to the host transfer memory 105 is executed (step S203).

  Next, it waits for the transfer of 256 KB data from the USB device 108 to the USB host transfer memory 105 (step S204).

  When the transfer is completed, the data processing block 106 is notified that the 256 KByte data transfer is completed (step S205).

  The data processing block 106 performs necessary data processing using the data for 256 KBytes for which the transfer held in the USB host transfer memory 105 has been completed (step S206).

  When necessary data processing is completed, it is checked whether there is a subsequent transfer (step S207). If there is a subsequent transfer, the processing returns to step S203 and the same processing is performed.

  On the other hand, when the transfer for the requested size generated from the data processing block 106 is completed, the transfer is completed (step S208).

  By performing the transfer in this way, the transfer of the data read request (step S202) to the USB device 108, which was conventionally required for each size of the USB host transfer memory 105, that is, 256 KBytes in this case, is performed once. The transfer efficiency can be improved.

  If the transfer size set for the USB host controller 103 in step S203 is smaller than the USB host transfer memory 105, the same processing can be performed.

  The operation shown in the flowchart of FIG. 2 is basically controlled by the temporary transfer interruption processing block 102. However, since the temporary transfer interruption processing block 102 is assumed to be software operating on the CPU 101, the CPU 101 and the temporary transfer interruption processing block 102 in FIG. Is called.

[Embodiment 2]
The operation of the USB host system according to the second embodiment of the present invention will be described with reference to FIG. The schematic configuration of the USB host system of the second embodiment is the same as that of the first embodiment shown in FIG.

  FIG. 3 is an operation flowchart according to the second embodiment of the present invention. In the second embodiment, the USB host controller 103 is used, and data is written to the USB device 108 from the USB host transfer memory 105, which is a memory area that can be used for transfer by the USB host controller 103 in the main memory 104. Will be described. In the description, it is assumed that the data size that the data processing block 106 writes to the USB device 108 is 1024 Kbytes, and the size of the USB host transfer memory 105 is 256 Kbytes.

  When a data write request of 1024 Kbytes to the USB device 108 is generated from the data processing block 106 (step S301), a data write request of 1024 Kbytes that is the write request size is sent to the USB device 108 (step S302).

  Next, the data processing block 106 sets 256 KBytes of data to be written to the USB device 108 in the USB host transfer memory 105 (step S303).

  When the setting is completed, the USB host controller 103 is set to write data for 256 KBytes, which is the size of the USB host transfer memory 105, from the USB host transfer memory 105 to the USB device 108. Transfer from the host transfer memory 105 to the USB device 108 is executed (step S304).

  Next, it waits for the transfer of 256 KB data from the USB host transfer memory 105 to the USB device 108 (step S305).

  When the transfer is completed, the data processing block 106 is notified that the 256 KByte data transfer has been completed (step S306).

  The data processing block 106 confirms whether or not all writing to the USB device 108 has been completed (step S307). If there is remaining write data, the data processing block 106 writes to the USB device 108. Data for the next 256 Kbytes is prepared (step S308) and set in the USB host transfer memory 105 (step S303).

  On the other hand, when all writing to the USB device 108 is completed and no write data remains, the transfer is completed (step S309).

  By performing the transfer in this way, the transfer of the data write request to the USB device 108 that is conventionally required for each size of the USB host transfer memory 105, that is, 256 KBytes in this case can be realized by only one transfer ( Step S302) and transfer efficiency can be improved.

  If the transfer size set for the USB host controller 103 in step S303 is equal to or smaller than the USB host transfer memory 105, the same processing can be performed.

[Embodiment 3]
FIG. 4 is a block diagram showing a schematic configuration of the USB host system according to the third embodiment of the present invention. In FIG. 4, 400 is a USB host system, 401 is a CPU, 402 is USB host control software having a temporary transfer interruption process, 403 is a USB host controller having a USB host function, 404 is a central processing unit and a USB host controller. The main memory to be accessed, 405 is a USB host transfer memory for storing data that the USB host controller 403 transfers to and from the USB device in the main memory 404, and 406 is audio data and video transferred by USB. An AV processing block for processing data, 407 is a USB bus, and 408 is a USB device connected to the USB host controller 403 via the USB bus 407. The AV processing block 406 includes a decoding unit that decodes audio data and video data.

  In the temporary transfer interruption process of the USB host control software 402 described above, when data transfer is performed between the USB host controller 403 and the USB device 408, the USB host transfer memory 405 is transferred between the USB host controller 403 and the USB device 408. Data transfer between the USB host controller 403 and the USB device 408 is temporarily interrupted each time transfer of transfer data of a predetermined size equal to or smaller than the memory size is executed, and predetermined processing for stored data in the USB host transfer memory 405 is performed Is completed and the USB host transfer memory 405 becomes usable, and data transfer between the USB host controller 403 and the USB device 408 is resumed.

  In the third embodiment, for transferring data between the USB host system 400 and the USB device 408, the USB Mass Storage Class Bulk-Only Transport protocol (hereinafter referred to as the BOT protocol) standardized by the USB standard. An example of using will be described.

  FIG. 5 is a schematic diagram illustrating a transfer sequence when the USB host system 400 reads data from the USB device 408. In the description, the data size read from the USB device 408 by the AV processing block 406 is assumed to be 1024 Kbytes, and the size of the USB host transfer memory 405 is assumed to be 256 Kbytes.

  In the third embodiment, data transferred by USB is processed in the AV processing block 406. For example, audio data and video data are decoded.

  The AV processing block 406 requests the USB host control software 402 to transfer the data to be processed from the USB device 408 (step S501).

  Upon receiving the request, the USB host control software 402 is a command for issuing a transfer request to the USB device 408 to the USB host controller 403, and performs Command Block Wrapper (hereinafter referred to as CBW) transfer determined by the BOT protocol. Set (step S502: CBW transfer request). The CBW has a location for setting a data size to be read from the USB device 408, and sets a requested size from the AV processing block 406, which is 1024 KB.

  Next, the USB host controller 403 executes CBW transfer to the USB device 408 (step S503).

  When the CBW transfer is completed and a completion notification is received (step S504), the USB control software 402 makes a request to receive data of 256 KBytes, which is the size of the USB host transfer memory 405, from the USB device 408 in order to perform actual data transfer. The USB host controller 403 is set (step S505).

  Next, the USB host controller 403 receives 256 KByte data from the USB device 408 (step S506).

  When the reception is completed and a completion notification is received (step S507), the USB host control software 402 notifies the AV processing block 406 that the data transfer of 256 KBytes has been completed (step S508).

  Receiving the notification, the AV processing block 406 executes AV processing such as decryption using the received data (step S509).

  When the AV processing block 406 has processed 256 KBytes of data, a data re-request is made to perform subsequent data transfer (step S510). Receiving the data re-request, the USB host control software 402 sets a data reception request for the next 256 Kbytes in the USB host controller 403 (step S511), and performs transfer.

  The above transfer request processing and AV processing are repeatedly executed, and finally AV processing of data for 1024 Kbytes is executed. When the data transfer for 1024 Kbytes is completed and a completion notification is received (step S512), the USB host control software 402 is a command for receiving a series of transfer statuses from the USB device 408, and is determined by the BOT protocol. The command status wrapper (hereinafter referred to as CSW) transfer is set in the USB host controller 403 (step S513: CSW transfer request).

  The USB host controller 403 performs CSW transfer (step S514), and notifies the AV processing block of the result as a transfer status via the USB host control software 402 (step S515).

  By performing the above processing, transfer of CBW and CSW is required for each 256 Kbytes which is the size of the USB host transfer memory 405, whereas transfer memory is used for each CBW transfer and CSW transfer. Transfer of a size larger than 405 is possible, saving the time required for the transfer of CBW and CSW, and improving the transfer speed.

  In the third embodiment, the transfer size set in the USB host controller 403 has been described as 256 Kbytes, but the same effect can be obtained if the transfer size to be set is equal to or smaller than the size of the USB host transfer memory 405. Also, when data is written from the USB host system 400 to the USB device 408, the transfer can be performed by the same procedure.

  The USB host system according to the present invention has a high-speed transfer function by improving the efficiency of data transfer with a USB device, and is useful for audio equipment that reads and writes AV data from a USB device, a digital television, a digital video record, and the like. In addition, it can process AV data and can be applied to other AV systems using a USB host.

It is a block diagram which shows the USB host system schematic structure of Embodiment 1, 2 in this invention. 3 is a flowchart showing an operation in the first embodiment. 10 is a flowchart showing an operation in the second embodiment. It is a block diagram which shows the USB host system schematic structure of Embodiment 3 in this invention. FIG. 10 is a schematic diagram showing a transfer sequence in the third embodiment.

Explanation of symbols

100 USB host system 101 CPU
102 Temporary transfer interruption processing block 103 USB host controller 104 Main memory 105 USB host transfer memory 106 Data processing block for processing data transferred by USB 107 USB bus 108 USB device 400 USB host system 401 CPU
402 USB host control software having temporary transfer interruption process 403 USB host controller 404 Main memory 405 USB host transfer memory 406 AV processing block for processing AV data transferred by USB 407 USB bus 408 USB device

Claims (8)

  Access is made from a central processing unit, a USB host controller having a USB host function, the central processing unit and the USB host controller, and the USB host controller and the USB host controller are connected via a USB bus. When data transfer is performed between a main memory including a USB host transfer memory that can be used for temporary storage of transfer data transferred between connected USB devices, and the USB host controller and the USB device. The data transfer between the USB host controller and the USB device is temporarily performed each time transfer of transfer data having a predetermined size less than the memory size of the transfer memory is executed between the USB host controller and the USB device. The storage in the transfer memory A USB host system comprising a temporary transfer interruption processing unit that waits for completion of predetermined processing for data and the transfer memory becomes usable, and resumes data transfer between the USB host controller and the USB device .   The USB host system according to claim 1, wherein the USB host controller is compliant with an EHCI (Enhanced Host Controller Interface) standard.   The USB host system according to claim 1, wherein the USB host controller conforms to an OHCI (Open Host Controller Interface) standard.   The USB host system according to claim 1, wherein the USB host controller conforms to a UHCI (Universal Host Controller Interface) standard.   The USB host system according to any one of claims 1, 2, 3, and 4, wherein a command used for USB transfer conforms to a USB mass storage standard. A data transfer method for transferring data between a USB host system and a USB device,
A first step in which the USB host system requests the USB device to transfer data larger than the memory size of the transfer memory;
A second step in which the USB device makes a transfer setting to the USB host controller that is less than or equal to the memory size of the transfer memory;
A third step in which the USB device performs data transfer for a transfer size set in the USB host controller;
A fourth step of determining whether or not the transfer of the data requested to be transferred in the first step is completed,
In the fourth step, when it is determined that the data transfer is not completed, the second to fourth steps are repeated.   The USB device is compatible with the USB mass storage standard, and in the transfer between the USB device and the USB host system, a data transfer request made by the USB device before the first step is sent to the CBW (Command Block). The data transfer method according to claim 6, wherein the data transfer method is performed by a Wrapper. A video / audio processing system comprising a USB host system and a USB device connected to the USB host system and inputting / outputting video / audio signals to / from the USB host system,
The USB host system is accessed from a central processing unit, a USB host controller having a USB host function, the central processing unit and the USB host controller, and the USB host controller and the USB host controller are accessed. A main memory including a USB host transfer memory that can be used for temporary storage of transfer data including video and audio signals transferred to and from the USB device connected via the USB bus; and the USB host transfer memory A decoding unit that decodes the stored transfer data composed of the video and audio signals; and when performing data transfer between the USB host controller and the USB device, between the USB host controller and the USB device, Less than the memory size of the transfer memory Each time transfer of transfer data of a predetermined size is executed, data transfer between the USB host controller and the USB device is temporarily interrupted, and predetermined processing by the decoding unit for stored data in the transfer memory is completed. A video / audio processing system comprising a temporary transfer interruption processing unit that waits for the transfer memory to become usable and resumes data transfer between the USB host controller and the USB device.

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