JP2006023986A - Method for copying data and card reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for copying data between a plurality of memory cards without occupying a system bus and a main memory. <P>SOLUTION: A card reader which is an apparatus for copying data from a first memory card to a second memory card comprises: a multicard interface connected to the first memory card and the second memory card and capable of accessing data stored in the first and second memory cards; a bus controller connected to a system bus and receiving a copy instruction sent from the system through the system bus; and a direct memory access controller capable of directly copying data from the first memory card to the second memory card without occupying the system bus when the bus controller receives the copy instruction sent from the system. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method and an apparatus for directly copying data between a plurality of memory cards, and in particular, without using an internal direct memory access (DMA) controller in cooperation with a software driver without copying a memory or a system bus. The present invention relates to a method for transferring data between various types of memory cards.

  Flash memory cards are convenient and portable because of their small size. However, for example, standards between various memory cards such as memory stick (MS), safe digital (SD), smart media (SM), and xD picture (XD) are not interchangeable. For this reason, multi-card readers have become popular due to demand for convenience. Conventional multi-card readers typically use Universal Serial Bus (USB), Low Pin Count (LPC), or Peripheral Device Interconnect Interface (PCI) for data transfer.

  In a conventional multi-card reader using a PCI interface, when data is read in order to copy data from the first card reader to the second card reader, the following components are used: the first memory card, direct memory access (DMA). ) Controller, PCI bus, South Bridge, North Bridge and main memory are occupied in order. Similarly, when data is written from the main memory to the second memory card, the following components are occupied in sequence: main memory, north bridge, south bridge, PCI bus, DMA controller and finally the second memory card. The Therefore, the PCI bus resources are occupied twice, the central processing unit (CPU) is interrupted twice, and the main memory is accessed twice.

  As shown in FIG. 1, the data of the conventional externally connected PCI devices 20, 21, and 22 inevitably pass through the system bus 23, the north and south bridges 25, and the main memory 24 regardless of whether they are read or written. Occupy.

  FIG. 2 shows a process of copying from the memory card 16 to the memory card 17 when the multi-card reader 27 is inserted into the system bus 14. First, a copy command is issued from the operating system 10 to the card reader drivers 8 and 9. The card reader driver 8 corresponds to the card reader 3, and the card reader driver 9 corresponds to the card reader 4. The DMA controller 1 and the card readers 3 to 4 are subsequently initialized by a copy command received by the bus slave 7 in the bus controller 13. The operating system 10 then confirms with an interrupt request 11 sent through the bus master 6 and informs the start of the copy process.

  After the initialization is completed, the data is transferred from the card reader 3 to the DMA controller 1 via the system bus 14 controlled by the bus master 6 through the north and south bridges 25 and finally written in the main memory 24. .

  Therefore, data is read from the main memory 24, transferred to the DMA controller 1 again through the north and south bridges 25 via the system bus 14 controlled by the bus master 6. The copy process is completed when data is written to the memory card 17 of the card reader 4 by the DMA controller 1. When complete, an interrupt request is sent simultaneously to the operating system 10 by the bus master 6 to inform the system that the copy process is complete.

  In conventional methods, data is read and written by direct memory access techniques and components are occupied in the following order: Memory card 16, card reader 3, DMA controller 1, bus master 6, system bus 14, north and south bridge 25, main memory 24, north and south bridge 25, system bus 14, bus master 6, DMA controller 1, card reader 4 and 13 steps in total for the memory card 17. Thus, the system is interrupted twice. Conventional methods place a significant burden on the PCI bus, waste bandwidth, and create a transfer bottleneck between the main memory and the PCI bus.

An object of the present invention is to provide a method for copying data between a plurality of memory cards without occupying a system bus and a main memory.
The method provided by the present invention is referred to as a hidden direct memory access (hidden DMA) transfer, and a multi-card reader used in this method is also provided.

  The multi-card reader includes a multi-card interface, a bus controller, and a DMA (direct memory access) controller. The multi-card interface further includes a plurality of slots of various types, and supports memory cards of different standards. The bus controller includes a bus master and a bus slave, and each controls a specific operation. The DMA controller is the main processor for data transfer and operates all data flowing between the card reader and the system under the control of the system driver.

  When data is copied from the first memory card to the second memory card, the following steps are required. First, a copy command sent from the system by the system bus is received. The data is subsequently read from the first memory card by the first card reader after receiving a copy command. Finally, the data is written to the second memory card by the second card reader without occupying the system bus. Thus, the memory and system bus are not occupied by the data copying process, and can inform the system that the copying process has begun with only one interruption. The internal flag is activated when the system confirms the interruption, and the copy process is determined to be complete when the flag value is a specific value.

  Thus, using the hidden direct memory access transfer method according to the present invention, only the following components are occupied in order. The memory card 16, the card reader 3, the DMA controller 1, the card reader 4, and the memory card 17 are all required to make a single system interruption request in five steps. Compared to 13 steps and 2 interruptions of the conventional system, the method of the present invention is faster and more efficient.

  With the hidden DMA transfer method according to the present invention, data is transferred between memory cards directly by an internal DMA (direct memory access) controller without accessing the main memory or occupying the PCI bus. To do. Only a notification instructing the completion of the copy process is waited at the central processing unit.

  In order that the objects, features, and advantages of the present invention will be more clearly understood, embodiments will be described below in detail with reference to the drawings.

A detailed description of the present invention is provided below.
As shown in FIG. 3, the multicard reader 27 is plugged into the system bus 14 of the computer system and controlled by instructions issued from the operating system 10 through the card readers 8 and 9. The multi-card reader 27 includes a bus controller 13 and a DMA controller 1, and card readers 2 to 5 are installed therein. The bus controller 13 is a combination of a bus master 6 and a bus slave 7. The bus master 6 guides the system bus 14 during data transfer, and the bus slave 7 receives an instruction issued from the operating system 10 through the system bus 14 and responds to the operating system 10 using a flag value.

  The DMA controller 1 guides all the data flow of the multi-card reader 27 and can copy data between any driver under the direction of the driver 19. For example, card reader to card reader, card reader to system, or system to card reader.

  Memory cards 15 to 18 of any standard including a memory stick (MS), safe digital (SD), smart media (SM), and xD picture (XD) are inserted into corresponding card readers 2 to 5. The system bus 14 is compatible with Peripheral Device Interconnect Interface (PCI), ISA (Industrial Standard Architecture), or Low Pin Count (LPC).

  FIG. 3 illustrates a state where data is copied from the memory card 16 to the memory card 17. The multicard reader 27 includes a bus controller 13 connected to the system bus 14. The operating system 10 controls the multi-card reader 27 in cooperation with the card reader driver 8 or 9. The card reader 3 reads the card reader driver 8, and the card reader 4 reads the card reader driver 9. The copy command is issued from the card reader driver 8 under the direction of the operating system 10 and received by the slave 7 placed in the bus controller 13 via the system bus 14. And the card reader 4 is initialized.

  After initialization is complete, data is read from the card reader 3 by the DMA controller 1 and an interrupt request is sent to the operating system 10 through the bus master 6 located in the bus controller 13 at the same time, and the copy process begins. Let the system know that The card reader driver 9 is then instructed by the operating system 10 to monitor the flag value in the DMA controller 1.

  Data is written to the memory card 17 by the DMA controller 1 through the card reader 4. When complete, the flag is set to a specific value to inform the system 10 that the copy process is complete.

  In another embodiment, an interconnect mechanism is provided in the card reader drivers 8 and 9 to automate the initialization of the corresponding card reader without occupying the operating system 10. The operating system 10 is only required to issue instructions, and the card reader driver completes the remaining tasks and frees the operating system 10 from the burden of completing each complex component initialization step. .

  Thus, with the hidden DMA transfer method according to the present invention, data is directly stored in the internal DMA (direct memory access) controller without accessing the main memory or occupying the PCI bus. Transfer between cards. Only notifications that direct the completion of the copy process are expected at the central processing unit (CPU).

  Thus, data transfer occupies the following components in order: In other words, the memory card 16, the card reader 3, the DMA controller 1, the card reader 4, and the memory card 17 are all in five steps, and the system 10 is required to request only one system interruption. Conventionally, compared to 13 steps and 2 interruptions, the method of the present invention is more efficient and faster and can reduce the consumption of system resources.

  The preferred embodiments of the present invention have been described above, but this does not limit the present invention, and a few changes and modifications that can be made by those skilled in the art without departing from the spirit and scope of the present invention. It is possible to add. Accordingly, the scope of the protection claimed by the present invention is based on the scope of the claims.

6 is a flowchart illustrating data transfer based on related technology. 1 is a schematic diagram of a PCI DMA structure based on related technology. FIG. 1 is a schematic diagram of a hidden direct memory access (hidden DMA) structure according to the present invention. FIG.

Explanation of symbols

1 Direct memory access controller 2, 3, 4, 5 Card reader 6 Bus master 7 Bus slave 8, 9 Card reader driver 10 Operating system 11, 12 Interrupt request 13 Bus controller 14 System bus 15, 16, 17, 18 Memory card 19 Drivers 20, 22 Peripheral device interconnection interface 21 Peripheral device interconnection interface (master)
23 Peripheral Device Interconnect Interface Bus 24 Main Memory 25 North and South Bridge 26 Central Processing Unit (CPU)
27 Multi-card reader

Claims (10)

A card reader device for copying data from a first memory card to a second memory card,
A multi-card interface for connecting to the first memory card and the second memory card and accessing data stored therein;
A bus controller connected to the system bus and receiving a copy command sent from the system by the system bus;
A direct memory access controller for copying data directly from the first memory card to the second memory card without occupying the system bus when the copy command sent from the system is received by the bus controller;
Including card reader device. The apparatus according to claim 1, wherein a standard of the system bus is either PCI or ISA. The apparatus according to claim 1 or 2, wherein a standard of the first memory card and the second memory card is one of a memory stick, safe digital, smart media, and XD picture. The bus controller further includes a bus master, sends a bus control request to the system, and communicates with the system bus or a device in the system by the system bus. apparatus. The apparatus according to claim 1, wherein the bus controller further includes a bus slave, receives the copy command through the system bus, and sends a flag from the direct memory access controller to the system. Receiving a copy command sent from the system through the system bus;
After receiving the copy command, reading data from the first memory card through the first card reader;
Writing directly to the second memory card through the second card reader without occupying the system bus;
To copy data between multiple memory cards including The method of claim 6, further comprising initializing the direct memory access controller, the first card reader, and the second card reader after receiving the copy command. 8. The method according to claim 6 or 7, further comprising the step of sending an interrupt request to the system through a bus master in a bus controller after receiving the copy command to inform the system that the copy command has been executed. . The method according to any one of claims 6 to 8, further comprising the step of setting a flag in the direct memory access controller to a specific value after writing data to the second memory card. Receiving a copy command sent from the system through the system bus;
After receiving the copy command, initializing the direct memory access controller, the first card reader, and the second card reader;
After receiving the copy command, sending a suspension request to the system through a bus master in a bus controller to inform the system that the copy command has been executed;
After receiving the copy command, reading data from the first memory card through the first card reader;
Writing directly to the second memory card through the second card reader without occupying the system bus;
After writing data to the second memory card, setting a flag in the direct memory access controller to a specific value;
To copy data between multiple memory cards including

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