JP4830397B2 - Memory card and control method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily carry out transfer of data written in a memory card from a digital camera not by operations on a host apparatus to which the digital camera is attached. <P>SOLUTION: An externally controllable communication control part is provided in the memory card such that contents of a memory in the memory card can be read by control from the outside. In a mobile apparatus such as the digital camera, radio transfer from the digital camera of image data written in the memory card can be realized without particular change such as installation of a driver. In other words, it can be applied to existing digital cameras. <P>COPYRIGHT: (C)2006,JPO&amp;NCIPI

Description

  The present invention relates to a memory card that is used by being detachably attached to an information device, a control method thereof, an access control method for the memory card, and a computer program, and more particularly, a wireless communication function that is stored in a memory. The present invention relates to a memory card that wirelessly transmits data to an external device, a control method thereof, an access control method for the memory card, and a computer program.

  More specifically, the present invention relates to a memory card for easily transferring data stored in a memory to an external device by wireless communication, regardless of an operation on the attached host device, a control method therefor, and a memory card. Access control method and computer program, and in particular, it is not necessary to install driver software for communication control in the installed host device (ie, by independent processing operation outside the control of the host device) and stored in the memory The present invention relates to a memory card that wirelessly transmits the data to an external device, a control method thereof, an access control method for the memory card, and a computer program.

  The present invention also relates to a memory card that performs wireless data transmission operation outside the control of the host device while receiving power from the mounted host device, a control method thereof, an access control method for the memory card, and a computer program. In particular, the present invention relates to a memory card that performs a wireless data transmission operation outside the control of the host device while avoiding power supply interruption from the installed host device, a control method thereof, an access control method for the memory card, and a computer program.

  Along with recent technological innovations, various types of computer files consisting of various media such as text, images, and audio, such as personal computers (PCs), PDAs (Personal Digital Assistants), digital cameras, and portable media players. Information equipment has been developed and marketed. Many of the main information devices have interfaces such as a card slot and a connector for detachably mounting a cartridge type memory device such as a memory card or a USB memory. The memory card has a plurality of standards such as “MEMORYSTICK (registered trademark)” and “SD (Secure Digital) card”. Hereinafter, the removable memory device will be collectively referred to as “memory card”. To.

  For example, in a digital camera, a captured image is encoded into a predetermined file format such as JPEG (Joint Picture Experts Group) or MPEG (Moving Picture Experts Group), and then stored in a memory card. In such a case, a large number of images that cannot be stored in a relatively small-capacity device built-in memory can be stored. Also, when the memory card is full of stored data, a new storage capacity for storing the captured image can be easily obtained by replacing the memory card with another memory card.

  In addition, image files captured on a digital camera are moved to other information devices such as personal computers for image processing such as image quality adjustment and re-encoding, and image management in the form of databases or albums. Can be. Alternatively, the image can be enjoyed as a photograph by transferring it to a television receiver and displaying the captured image in a large size, or by transferring the image file to a printer and printing it out.

  Here, as a method of moving an image or other data on a memory card between devices, it is common to take out the memory card and attach it to a destination device. Alternatively, data transmission can be performed via a wired or wireless transmission path using a wired interface or a wireless interface between a host device in which a memory card is mounted and an information device as a data transfer destination. In particular, when the latter wireless communication is used, there is no need to change the connector and route the cable every time data is transmitted, which is highly convenient.

  FIG. 9 shows an example of wireless image transmission. In the figure, a digital camera is assumed as a mobile device. The digital camera stores captured images as image data in an internal memory or an external memory card. When wireless transmission is performed, target image data is read from the built-in memory or an external memory card, and transferred to an image reproduction device such as a PC, a television, or a printer via a wireless interface. Of course, a wireless interface module is also provided as an adapter on the receiving device side such as a PC, television, or printer. After the image data is transferred through the wireless transmission path, the image data is displayed and stored on the PC, displayed on the screen on the television, and printed out on the printer.

  In order to perform wireless data transmission as shown in the figure, a wireless interface module must be provided on the digital camera side which is a data transmission source. In addition, when the transmission source is a device that does not have a built-in wireless interface, it is necessary to equip a wireless interface including, for example, an external adapter. In addition, as a wireless communication function used for data transmission, Bluetooth communication and wireless LAN such as IEEE802.11 are assumed.

  For example, proposals have been made for external memory media with a built-in wireless communication function (see, for example, Patent Document 1). In addition to wired communication means for transferring data to and from the attached host device via a physical connection means such as a connector, the external memory medium is externally connected via a short-range wireless communication network such as Bluetooth communication. Short-range wireless communication means for transmitting / receiving data to / from the communication network. Therefore, a host device such as a digital camera that is a data transmission source does not have a wireless interface, but is equipped with such an external memory medium, and a short-distance wireless communication means in the memory medium is installed. Data can be sent to and received from the communication network by driving.

  FIG. 10 shows a configuration example of a memory card with a wireless communication function. In the figure, reference numeral 10 is a memory card with a wireless communication function, reference numeral 11 is a host device such as a digital camera, reference numeral 2 is a data transfer destination printer, or an external device such as a data output destination TV monitor. It is.

  A memory card 10 with a wireless communication function includes a flash memory 6, a memory control unit 7, and an interface unit 8 with a host device 11 that are basic components as a memory card. For example, a wireless unit 4 such as Bluetooth communication and a communication control unit 5 are added to the memory card 11. The communication control unit 5 controls a communication protocol for wireless communication. The antenna is mounted as a reference number 3 on the memory card 10 side with the wireless communication function and as a reference number 9 on the external device 2 side.

  The host device 11 normally performs an access operation for storing and reading data in the flash memory 6 via the interface unit 8 and the memory control unit 7. When sending an image in the flash memory 6 to the external device 2, the host device 11 reads out target data from the flash memory 6 via the interface unit 8 and the memory control unit 7. Next, the host device 11 performs wireless transmission to the external device 2 that is a data transfer destination via the interface unit 8, the communication control unit 5, the wireless unit 4, and the antenna 3.

  Here, in order to realize wireless communication, it is necessary to control a wireless communication function according to a predetermined communication protocol such as Bluetooth communication or IEEE802.11. In the example shown in FIG. 10, on the host device side where the wireless interface module is mounted, driver software for operating the wireless communication function in the interface module according to the protocol (that is, controlling the communication control unit 5) is provided. It is cumbersome for the user because it needs to be installed.

  In addition, in some cases, such as a digital camera, other portable devices, and embedded devices, the driver software installation operation itself may not be possible. In this case, even when an external memory medium equipped with a wireless communication function as described above is used, the wireless communication function cannot be used, and eventually the data stored in the memory card is not stored. To move, traditional methods such as memory card replacement and wired connection must be used.

  Further, operations related to communication processing such as selection of a file to be transferred must be performed on the user interface of the attached digital camera, and the operation is complicated.

JP 2001-77878 A

  An object of the present invention is to provide an excellent memory card having a wireless communication function and capable of wirelessly transmitting data stored in a memory to an external device, a control method thereof, an access control method for the memory card, and a computer program Is to provide.

  A further object of the present invention is to provide an excellent memory card and a control method therefor, which can easily perform wireless transmission operation of data stored in a memory to an external device regardless of an operation on a mounted host device. An object is to provide an access control method for a memory card and a computer program.

  A further object of the present invention is that there is no need to install driver software for communication control in an installed host device (ie, by independent processing operation outside the control of the host device), and the data stored in the memory is transferred to the external device. An object of the present invention is to provide an excellent memory card and its control method capable of performing wireless transmission, an access control method for the memory card, and a computer program.

  A further object of the present invention is to provide an excellent memory card capable of performing wireless data transmission operation outside the control of the host device while receiving power from the attached host device, a control method therefor, and an access control method for the memory card. And providing a computer program.

  A further object of the present invention is to provide an excellent memory card, its control method, and memory card capable of performing wireless data transmission operation outside the control of the host device while avoiding power supply interruption from the installed host device. It is to provide an access control method and a computer program.

The present invention has been made in consideration of the above problems, and the first aspect of the present invention is a memory card used by being mounted on a host device,
Memory to store data,
Wired communication means detachably connected to the host device;
Wireless communication means for communicating with external devices via a wireless transmission path;
Controlling the access operation from the host device via the wired communication means to the memory, the access operation from the external device via the wireless communication means, and the wireless communication operation by the wireless communication means A memory and communication control means;
A memory card.

  Here, the wireless communication unit is configured to transmit an operation of transmitting data read from the memory to the external device via a wireless transmission path, independent of a communication operation from the host device connected to the wired communication unit. And do it. A specific example of such a wireless communication means is a reflection that receives an unmodulated carrier transmitted from a reflected wave reader and backscatters a reflected wave signal obtained by modulating the reflected wave according to transmission data. It is a vessel.

  According to the reflected wave transmission system, the reflected wave can be modulated only by a switching operation such as changing the load impedance of the antenna or giving a phase difference to the reflected wave signal path. It should be fully understood that a data transmission path with low power consumption can be realized.

  Many information devices include a connector or an interface for detachably mounting a cartridge type memory device such as a memory stick, a memory card, or a USB memory. This type of memory card is provided with short-range wireless communication means, so that it is not necessary to change the connector every time data is transmitted and to route the cable. However, it is troublesome because it is necessary to install driver software for operating the wireless communication function in the module according to the protocol in the information device.

  On the other hand, in the memory card according to the present invention, the memory and the communication control means perform an access operation to the memory via the wired communication means and the wireless communication means, and the wireless communication means communicates with an external device. The wireless communication operation is controlled. The wireless communication means transmits the data read from the memory to an external device via a wireless transmission path, independently of the host device having the memory card attached thereto via the wired communication means. Can be done. That is, since the memory and the communication control means can control the wireless communication operation by the wireless communication control means outside the control by the host device, a driver for wireless communication control on the host device side where the memory card is mounted is provided. Even without installing software, an external device can access the memory using wireless communication. When the wireless communication unit is configured as a reflector in the reflected wave transmission system, the memory and the communication control unit may perform backscatter transmission of the transmission data read from the memory, and the wireless data transmission operation is performed by a memory card. There is no particular need for control by the host device to which is installed.

  Here, the memory and the communication control unit control an access operation from the host device to the memory via the wired communication unit according to a connection state of the external device in the wireless communication unit. In other words, the memory and the communication control unit alternatively perform an access operation from the host device via the wired communication unit to the memory and an access operation from the external device via the wireless communication unit. Do. Specifically, the memory and the communication control unit may access the memory from the host device via the wired communication unit while the wireless communication unit is performing a wireless communication operation with the external device. Is prohibited.

  As a result, it is possible to avoid malfunctions due to contention of access to the memory from both the wired communication means and the wireless communication means, and to smoothly perform a memory access request from an external device via the wireless communication means. Can be guaranteed. Of course, the access operation from the wireless communication means to the memory is prohibited during the period in which the data transfer operation to the memory is performed by the host device via the wired communication means.

  On the other hand, unlike the communication operation via the wired communication means, the communication operation by the wireless communication means has a risk that the communication being processed is interrupted. Therefore, in order to prevent the memory from being destroyed, the memory and the communication control unit accept only the read request to the memory from the external device via the wireless communication unit and do not permit the write request. You may do it.

One or more files can be stored in the memory. In this case, before Symbol memory and the communication control means, wherein in response to a request from said external device via said wireless communication means, the requested file or file information on a file stored in the memory Wireless transmission to the external device via wireless communication means. On the external device side of the data request source that has received the file information, a file list can be displayed based on the file information to select a desired file. Then, a file request can be made again.

  In addition, the memory card according to the present invention can be connected via the wired communication means as an imaging device that acquires image data as a host device. For example, a memory card is inserted into a memory slot of a digital camera. In such a case, the memory and the communication control means write the image data acquired by the imaging device into the memory via the wired communication means and receive an image data request from the external device via the wireless communication means. In response, the corresponding image data can be read from the memory and wirelessly transmitted from the wireless communication means to the external device. That is, the memory card can pull-distribute the image data to the data request source device that requests the image data.

  The memory card according to the first aspect of the present invention may further include an address storage unit that stores address information in the memory that is last accessed from the host device via the wired communication unit. . In such a case, in response to a request from the external device via the wireless communication unit, the memory and the communication control unit obtain address information stored in the address storage unit from the wireless communication unit to the external device. Wireless transmission to the device is possible.

  The last accessed address can be assumed to be the file that the user wants to see most. This is because the user has a habit of transferring data after confirming (i.e., previewing) the file he / she wants to see most. Alternatively, the user may specify transfer data by accessing the file most desired to be viewed last at the time of data transfer. In such a case, the host device or external device that is the data transfer destination acquires address information from the address storage unit, and then specifies the file that was last accessed based on the acquired address information. Then, data constituting a desired file can be requested to the memory card via the wired communication means or wireless communication means.

  In general, the memory card is driven by power supplied from a host device in which the memory card is mounted. That is, the memory and the communication control means perform an access operation to the memory and a wireless communication operation by the wireless communication means by power supply from a host device attached via the wired communication means.

  On the other hand, many host devices have a power saving function for battery operation. Because of this power saving function, in response to the timer that counts the time elapsed since the last event occurred in the memory card connected via the wired communication means timed out, the wired communication The power supply from the means to the memory card is stopped.

  However, since the memory card according to the first aspect of the present invention can perform the wireless communication operation with the external device via the wireless communication means without the intervention of the host device, the wireless communication operation can be performed. During the period of effective execution, the host device has a problem that the timer times out, power supply to the memory card is stopped, and data communication to the external device is interrupted. If the power of the memory card in communication is cut off halfway, the communication is forced to be interrupted and cannot be restored thereafter.

  Accordingly, the memory card according to the first aspect of the present invention generates a predetermined event for the host device via the wired communication means before the timer on the host device side times out, so that the wired communication is performed. There may be further provided power supply stop avoiding means for avoiding stop of power supply to the memory card from the means.

  The wired communication means includes an insertion / removal detection signal for notifying the host device of insertion / removal of the memory card, and the host device stops power supply when detecting the removal state of the memory card on the insertion / removal detection signal. In addition, power feeding is started in the inserted state. In such a case, the power supply stop avoiding means includes a communication interruption means for temporarily interrupting a wireless communication operation with the external device via the wireless communication means before the timer times out, and a wireless communication operation. When temporarily interrupted, a power supply restart is performed in which a pseudo disconnection state is formed on the insertion / extraction detection signal, power supply from the host device is stopped, power supply from the host device is resumed after returning to the insertion state It can be configured by means.

The second aspect of the present invention is a memory card used by being mounted on a host device,
Memory to store data,
Wired communication means detachably connected to the host device;
The memory and communication control means for controlling an access operation from the host device to the memory via the wired communication means;
An address storage unit for storing address information in the memory accessed last via the wired communication means;
A memory card. The memory and the communication control means are configured to send address information stored in the address storage unit in response to a request via the wired communication means.

  The present invention assumes a data communication system that performs data transmission between a memory card and information equipment via wireless communication means, or data transmission between a memory card and external equipment via wired communication means. . Here, when data is transferred between two devices, generally, a file to be transmitted and a file transfer destination are designated in the data transfer source device, and then the file transfer is performed. For example, when an image photographing apparatus such as a digital camera transfers a photographed image to a PC, after the image photographing apparatus is connected to the PC, a file to be transferred is designated, and then a transfer process to the PC is performed. Here, when the image capturing apparatus and the PC are connected by the above-described reflected wave transmission path, the user needs to perform both an operation for adjusting the directivity between both apparatuses and an operation for designating a transfer file. There is.

  However, in such a case, every time a file is sent, the user needs to connect the image transmission apparatus to the image display apparatus, which is troublesome. For example, when data transmission is performed via wireless communication means using reflected wave transmission, it is very troublesome to adjust the directivity to the image display device after sequentially specifying the file to be transferred.

  On the other hand, the memory card according to the second aspect of the present invention includes an address storage unit for storing address information in the memory accessed last. The last accessed address can be assumed to be the file that the user wants to see most. This is because the user has a habit of transferring data after confirming (i.e., previewing) the file he / she wants to see most. Alternatively, the user may specify transfer data by accessing the file most desired to be viewed last at the time of data transfer.

  In such a case, the host device or external device that is the data transfer destination acquires address information from the address storage unit, and then specifies the file that was last accessed based on the acquired address information. Then, data constituting a desired file can be requested to the memory card via the communication means.

According to a third aspect of the present invention, a file transfer from the memory in the memory card according to the second aspect is easily performed regardless of a user operation such as file selection or file name designation. Access control method,
Obtaining address information from the address storage unit;
Identifying the last accessed file based on the obtained address information;
Requesting data constituting the identified file to the memory card via the communication means;
An access control method for a memory card. In this access control method, the memory card can be accessed via a wireless communication means such as a reflected wave transmission line or via a wired communication means.

  On the host device or external device side that is the data transfer destination, by applying such an access control method, the address information is obtained from the address storage unit in the memory card, and then, based on the obtained address information, By specifying the last accessed file, data constituting the desired file can be requested to the memory card via the communication means.

According to a fourth aspect of the present invention, there is provided a memory comprising a memory for data storage and an address storage unit for storing address information accessed last in the memory, which is accessible from the outside via a communication means. A computer program written in a computer-readable format to execute access control on a card on a computer system, the computer system
Obtaining address information stored in the address storage unit;
Based on the acquired address information, the procedure to identify the last accessed file,
A procedure for requesting data constituting the identified file to the memory card via the communication means;
Is a computer program characterized in that

  The computer program according to the fourth aspect of the present invention defines a computer program described in a computer-readable format so as to realize predetermined processing on a computer system. In other words, by installing the computer program according to the fourth aspect of the present invention in the computer system, a cooperative action is exerted on the computer system, and the memory according to the third aspect of the present invention. The same effect as the access control method for the card can be obtained.

  According to the present invention, an excellent memory card having a wireless communication function and capable of wirelessly transmitting data stored in a memory to an external device, a control method thereof, an access control method for the memory card, and a computer program Can be provided.

  In addition, according to the present invention, an excellent memory card that can easily perform a transfer operation of data stored in a memory to an external device by wireless communication, regardless of an operation on the attached host device, and its memory card A control method, a memory card access control method, and a computer program can be provided.

  In addition, according to the present invention, it is not necessary to install communication control driver software in the attached host device (that is, by independent processing operation outside the control of the host device), and the data stored in the memory is transferred to the external device. It is possible to provide an excellent memory card and its control method, an access control method for the memory card, and a computer program.

  The memory card according to the present invention has a wireless communication function. For example, the memory card can be controlled from the outside so that driver software for communication control is not required on the digital camera side. A communication control unit is provided so that the contents of the memory in the memory card can be read by external control. As a result, the following effects can be obtained.

(1) A mobile device such as a digital camera can achieve wireless transmission of image data written from a digital camera to a memory card without special changes such as driver installation. That is, it can be applied to an existing digital camera.
(2) Mobile device manufacturers do not have to develop a wireless communication function and can increase the development speed.

  In addition, by adopting a reflected wave transmission method that modulates the reflected wave with respect to the received radio wave as the wireless communication function of the memory card, the function is configured with a small and small module area, and the power consumption required for communication operation is greatly increased. Can be reduced.

  Further, according to the present invention, it is possible to perform wireless data transmission operation outside the control of the host device while receiving power from the attached host device, an excellent memory card, its control method, and access control to the memory card. Methods and computer programs can be provided.

  Further, according to the present invention, it is possible to perform wireless data transmission operation outside the control of the host device while avoiding the power supply stop from the installed host device, and an excellent memory card and its control method. An access control method for a card and a computer program can be provided.

  Other objects, features, and advantages of the present invention will become apparent from more detailed description based on embodiments of the present invention described later and the accompanying drawings.

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

A. System Configuration FIG. 1 schematically shows the configuration of a wireless transmission system according to the first embodiment of the present invention. This system includes a digital camera 101, a memory medium 110 with a wireless communication function, a wireless reader 102, a television 106, and an infrared remote controller 108.

  The memory medium 110 with the wireless communication function is accommodated in a dedicated memory slot or the like (not shown) of the digital camera 101 and connected via the connector unit 112. The connector unit 112 constitutes a wired communication interface between the memory medium 110 with a wireless communication function and the digital camera 101. For example, the standard interface specification such as MEMORYSTICK (registered trademark), PC card, or USB is used. It shall comply.

  The digital camera 101 corresponds to a host device, detachably accommodates a memory medium 110 with a wireless communication function, and stores captured image data in the memory medium 110 with a wireless communication function. From the digital camera 101 side, an access request to the flash memory 114 is made to the memory / communication control unit 113 in the memory medium 110 with the wireless communication function via the connector unit 112, and the flash memory of the captured image is It is possible to write data to 114 and read data such as images stored in the flash memory 114. In addition, the memory media 110 with a wireless communication function is supplied with driving power from the digital camera 101 via the connector unit 112.

  The memory medium 110 with a wireless communication function includes a wireless unit 115 as a wireless communication interface with the wireless reader 102. The wireless unit 115 includes a transmitting unit 116 and a receiving unit 117 and can perform wireless transmission with the wireless reading apparatus 102. For example, the control signal 103 is wirelessly transmitted from the wireless reader 102, and in response to this, the response signal 104 such as JPEG image data is wirelessly transmitted from the memory medium 110 with the wireless communication function in the digital camera 101. Is done.

  As a wireless communication interface applied to the wireless unit 115, for example, IEEE 802.11, which is a wireless LAN standard, Bluetooth communication, reflected wave transmission, or the like can be used. The reflected wave transmission referred to here is backscatter communication in which a reflected wave signal obtained by modulating a received radio wave based on transmission data is transmitted. The modulation process of the reflected wave can be performed by switching the antenna load impedance or applying a phase difference in the reflected signal path.

  The wireless reader 102 is connected to an external video input terminal of the television 106 via a video cable 105, and the wireless reader 102 and the television 106 provide a function corresponding to an external device. That is, when the wireless reading device 102 acquires the image data stored in the memory medium 110 with the wireless communication function by wireless transmission, the wireless reading device 102 obtains the image data via the video cable 105 to the external video input terminal of the television 106. The video can be output and displayed on the screen of the television 106.

  In addition, the wireless reading device 102 includes a display unit 120 that displays the operation state of the device itself. For example, the display unit 120 indicates to the user that data is received from the memory medium 110 by wireless transmission.

  The television 106 and the wireless reading device 102 include infrared light receiving units 107 and 109, respectively, receive infrared commands and execute device operations in accordance with the commands. Further, the infrared remote controller 108 can give a control command for the television 106 or the wireless reader 102 to the infrared light receiving unit 107 as a control signal 118 made of infrared rays. In addition to general operation commands such as video channel switching control and volume adjustment, which are control commands for the television 106, the infrared remote control 108 is used to control wireless communication operations by the wireless reader 102, and further via the wireless reader 102. A control command for instructing access to the memory medium 110 with the wireless communication function in the digital camera 101 is included.

  For example, the user uses the infrared remote controller 108 to instruct the wireless reader 102 to read image data from the memory medium 110 with a wireless communication function in the digital camera 101 and output video to the television 106. At the same time, it is possible to instruct the television 106 to display and output the image data line-input from the cable 105.

  Next, the internal configuration of the memory medium 110 with a wireless communication function will be described in detail. As shown in FIG. 1, the memory medium 110 with a wireless communication function includes an antenna 111, a wireless unit 115, a flash memory 114, a memory / communication control unit 113, and a connector unit 112.

  The flash memory 114 is a substance of a memory space in the memory medium 110 with a wireless communication function, and is configured by a non-volatile semiconductor memory device that can be electrically erased and rewritten, such as an EPROM or an EEPROM. The access operation to the flash memory 114 is controlled by the memory / communication control unit 113.

  The memory medium 110 with a wireless communication function is wired to the digital camera 101 via the connector unit 112. The digital camera 101 as a host device makes an access request to the flash memory 114 to the memory / communication control unit 113 via the connector unit 112, and writes a captured image to the flash memory 114, or flash memory Data such as an image stored in 114 is read out.

  The conventional memory media does not have a wireless communication function. The memory / communication control unit 113 is also a simple memory control unit that performs a memory access operation to the flash memory 114 (see FIG. 10), and has a function of controlling the wireless communication function. Absent. In contrast, the memory medium 110 according to the present embodiment has a wireless communication function including the antenna 111 and the wireless unit 115, and the memory / communication control unit 113 includes the wireless unit 115 in addition to the memory access to the flash memory 114. The wireless communication operation is also controlled.

  Access operations such as data writing and reading to the flash memory 114 are controlled by the memory / communication control unit 113. The digital camera 101 and the memory medium 110 are wiredly connected via a connector unit 112, and the digital camera 101 as a host device receives a captured image through the memory access control by the memory / communication control unit 113. Writing to the flash memory 114 and reading of image data stored in the flash memory 114 are performed.

  In this embodiment, the wireless unit 115 can perform a wireless communication operation under the control of the memory / communication control unit 113 and can access the flash memory 114 through the memory / communication control unit 113. . Therefore, the wireless reading device 102 as an external device can make an access request to the memory / communication control unit 113 via the antenna 111 and the wireless unit 115 and access the flash memory 114 using wireless communication. it can. That is, since the memory medium 110 has a wireless communication function, it is not necessary to change the connector every time data is transmitted to an external device, and it is not necessary to route the cable.

  The memory medium 110 with the wireless communication function is supplied with driving power from the digital camera 101 via the connector unit 112. The supplied power is used to drive the flash memory and the flash memory by the memory / communication control unit 113. An access operation to the memory 114 and a wireless communication operation by the wireless unit 115 can be performed.

  The radio unit 115 includes a transmission unit 116 and a reception unit 117, and performs radio transmission using a 2.4 GHz band called, for example, an ISM (Industrial, Scientific and Medical (industrial scientific medical) band). The transmission unit 116 encodes and modulates transmission data, converts it to an analog signal, up-converts it to a radio signal, and sends it out from the antenna 111 to the radio transmission path. The receiving unit 117 converts the radio signal received by the antenna 111 into a down converter and a digital signal, and further performs decoding / demodulation processing to analyze the received data.

  When a communication protocol such as Bluetooth communication or IEEE 802.11 is applied to the wireless unit 115, driver software for realizing the protocol operation is installed in the information device on the host device side such as the digital camera 101 in which the memory medium 110 is mounted. Need to be and cumbersome. On the other hand, in the present embodiment, the memory / communication control unit 113 performs an access operation to the flash memory 114 performed through the wireless communication operation by the wireless unit 115 from the digital camera 101 loaded with the memory medium 110. Independently (ie, outside the control by the digital camera 101 as the host device), the control is performed by the wireless reader 102 connected wirelessly. Therefore, the data read from the flash memory 114 can be wirelessly transmitted between the memory medium 110 and the wireless reader 102 without mounting a device driver for communication control on the digital camera 101 side.

  For example, when wireless data is transmitted by applying a reflected wave transmission method in the wireless unit 115 (described later), a radio wave (unmodulated carrier) transmitted from the wireless reader 102 is received by the receiving unit 117 and received by the transmitting unit 116. A reflected wave signal obtained by modulating a reflected wave with respect to a radio wave based on transmission data is transmitted. In this case, the memory / communication control unit 113 may perform backscatter transmission by placing the data read from the flash memory 114 on the reflected wave, and such communication operation can be performed without the intervention of the host device.

  The memory medium 110 according to the present embodiment can access the flash memory 114 from both the wired communication path and the wireless communication path, and there is a problem that these access requests compete. Therefore, the memory / communication control unit 113 selectively performs any one of the access operations to ensure that the memory access request is smoothly performed. Specifically, while the wireless unit 115 performs a wireless communication operation with an external device, the memory / communication control unit 113 prohibits access to the flash memory 114 from the digital camera 101 as the host device. I am doing so. Further, during a period in which data transmission is performed from the digital camera 101 to the flash memory 114 via the connector 112, an access operation to the flash memory 114 via the wireless unit 115 is prohibited.

  In addition, the wireless transmission path in the wireless unit 115 is different from the wired interface, and there is a problem that communication during processing may be interrupted. Therefore, in this embodiment, in order to prevent memory destruction, the memory / communication control unit 113 accepts only a read request from the wireless unit 115 to the flash memory 114 and does not allow a write request. Yes.

  FIG. 2 schematically shows a functional configuration of the wireless reading apparatus 102 that receives image data such as JPEG or MPEG from the memory medium 110 with wireless communication function of FIG.

  The wireless reader 200 (102) transmits the control signal 103 to the memory medium 110 with a wireless communication function, and receives and demodulates the signal 104 transmitted from the memory medium 110 with a wireless communication function. If the received data is image data such as JPEG or MPEG, the decoding process is required. For this reason, the wireless reader 200 includes an antenna 201 in the 2.4 GHz band (described above), an antenna switch 202 that selectively connects the antenna 201 according to a transmission / reception operation, a reception unit 203, and a transmission unit 204. A communication control unit 205 and a JPEG decoder 206.

  In addition, an infrared light receiving unit 209 (107) for receiving a control signal 118 from the infrared remote controller 108 is added to the wireless reader 200, and the control signal from the infrared remote controller 108 is received and a communication control unit is received. An instruction is given to 205. For example, the user uses the infrared remote controller 108 to instruct the wireless reader 102 to read image data from the memory medium 110 with a wireless communication function in the digital camera 101 and output video to the television 106. be able to.

  In order to transmit a control signal from the wireless reading device 200, a primary-modulated baseband signal such as QPSK is given from the communication control unit 205 to the transmission unit 204. The transmission unit 204 up-converts and amplifies this modulated signal to the 2.4 GHz band, and transmits it from the antenna 201 via the antenna switch 202.

  On the other hand, in the memory medium 110 with the wireless communication function described above, the memory / communication control unit 113 reads the transmission data from the flash memory 114 and converts it into a QPSK modulated baseband signal. Then, the signal is converted into a 2.4 GHz band by the transmission unit 116 and transmitted from the antenna 111.

  On the wireless reading device 200 (102) side, when a transmission signal from the memory medium 110 is received by the antenna 201, it is passed to the receiving unit 203 via the antenna switch 202, and further demodulated to the original data by the communication control unit 205. Is done. The contact point of the antenna switch 202 is switched from the communication control unit 205 to the position a at the time of transmission and to the position b at the time of reception.

  The data demodulated by the communication control unit 205 is converted from JPEG data into an analog AV signal (for example, NTSC signal) by the JPEG decoder unit 206, and the image can be viewed on the connected television 106.

  The communication control unit 205 also performs communication control with the memory medium 110 with the wireless communication function, and transmits a control signal such as delivery confirmation information via the transmission unit 204. The communication control unit 205 can indicate the status of receiving data from the memory medium 110 by wireless transmission on the display unit 207 (120).

  FIG. 3 shows a control sequence in the wireless transmission system according to the present embodiment. The illustrated control sequence is between the digital camera 101 and the memory medium 110 with wireless communication function, the wireless reader 102, the television or other monitor display 106, and the infrared remote controller 108 operated by the user. Consists of communication operations.

  On the digital camera 101, the captured image is written into the flash memory 114 each time an image is captured. Further, when displaying a captured image on a viewer (not shown), data such as an image stored in the flash memory 114 is read out.

  Here, the user operates the infrared remote controller 108 when he / she wants to watch an image captured by the digital camera 101 on the television 106.

  The infrared remote controller 108 sends a video switching signal to the television 106. In response to the infrared command, the television 106 changes from the received image display mode to the external video input mode.

  Subsequently, the infrared remote controller 108 sends a display request signal to the wireless reader 102. In response to this, the wireless reader 102 sends a transfer request signal to the memory medium 110 with the wireless communication function.

  When receiving the transfer request signal, the memory medium 110 with the wireless communication function prohibits access from the digital camera 101 via the connector unit 112 in order to avoid contention for access to the flash memory 114. Then, the image data 104 is read from the internal flash memory 114 and sent to the wireless reader 102.

  When the wireless reader 102 receives the image data by wireless communication, the wireless reader 102 demodulates the received image data, further performs JPEG decoding and conversion into an analog video signal, and then outputs the video data to the television 106 via the cable 105.

  Alternatively, the infrared remote controller 108 sends not the display request signal but an information request signal requesting what kind of image file is stored to the wireless reader 102. In this case, the wireless reader 102 transfers an information request signal to the memory medium 110 with a wireless communication function, and an image information signal describing a list of image files is returned from the memory medium 110 with a wireless communication function. Then, a list of files is displayed on the television 106, and the user can make a display request again from the file list.

  The communication control unit 205 turns on the display unit 207 during data reception, and prompts the user to avoid operating the electronic device 101.

  In this way, the user can directly and concurrently operate a plurality of devices such as the operation of the television 106, the wireless reader 102, and the memory medium 110 with the wireless communication function in the digital camera 101 by using one infrared remote controller 108. Therefore, the operation can be simplified.

  In the sequence example shown in FIG. 3, one image is transferred. However, this content may of course be control of image processing such as list display, enlargement, reduction, and rotation. Further, the video switching signal can be omitted by using the video switching signal and the display start signal.

B. Data transmission using reflected wave communication between memory medium and external device As described above, the memory medium 110 has a built-in wireless communication function, and is wirelessly read independently of a host device such as the digital camera 101. A function of reading the flash memory 114 in the memory medium 110 from an external device such as the device 102 is provided. That is, the wireless communication operation in which the data read from the flash memory 114 is wirelessly transmitted by the memory / communication control unit 113 is wirelessly connected independently of the digital camera 101 loaded with the memory medium 110. This can be performed by a control operation by the apparatus 102. In such a case, data read from the flash memory 114 is wirelessly transmitted between the memory medium 110 and the wireless reader 102 without mounting a device driver for communication control on the digital camera 101 side. Can do.

  As a wireless communication interface for connecting the memory medium 110 with the wireless communication function and the wireless reader 102, for example, IEEE 802.11, which is a wireless LAN standard, Bluetooth communication, reflected wave transmission, or the like can be used.

  Here, the wireless LAN is originally designed and developed on the premise that it is used in a computer, and when it is installed in a mobile device, its power consumption becomes a problem. Many of the IEEE802.11b wireless LAN cards currently on the market have a power consumption of 800 mW or more when transmitting and 600 mW or more when receiving. This power consumption is a heavy burden for battery-powered portable devices. Even if the wireless LAN function is operated in a limited range and the transmission power is reduced, the power consumption cannot be significantly reduced. In particular, since transmission from an image input device such as a digital camera to the image display device is in a communication form in which the transmission ratio occupies the entire communication, wireless transmission means with low power consumption is still required. As for Bluetooth communication, the maximum transmission speed is as low as 720 kbps, and it is time-consuming and inconvenient for the recent high-quality image transmission.

  On the other hand, in the reflected wave communication system in which the reflector transmits the reflected wave signal obtained by modulating the received radio wave by backscatter transmission, particularly in the communication mode in which the transmission ratio from the reflector side occupies most of the communication. , Low power consumption can be realized.

  The reflected wave transmission system includes a reflector that modulates a reflected wave with respect to a received radio wave and transmits data, and a reflected wave reader that reads data from a reflected wave signal from the reflector. During data transmission, the reflected wave reader transmits an unmodulated carrier. On the other hand, the reflector transmits data by performing a modulation process corresponding to the transmission data on the unmodulated carrier by using a load impedance operation such as on / off of the end of the antenna, for example. The reflected wave reader side can receive the reflected wave, demodulate and decode it, and acquire transmission data.

  The reflector includes, for example, an antenna that reflects incident continuous wave radio waves, a transmission data generation circuit, and an impedance change circuit that changes the impedance of the antenna in accordance with the transmission data (for example, Japanese Patent Laid-Open No. 01-2001). No. 1822782).

  In the reflected wave transmission system, the antenna switch for changing the load impedance of the antenna (that is, modulating the reflected wave) is generally composed of a gallium arsenide IC, and its power consumption is several tens of μW or less. The average power when performing data transmission is 10 mW or less in the case of the delivery confirmation method, and data transmission is possible at several tens of μW in the one-way transmission. This is an overwhelming performance difference compared to the average power consumption of a general wireless LAN (see, for example, JP-A-2005-64822). Therefore, even when an information storage terminal device is mounted on a battery-driven mobile device such as a digital camera, the battery life can be greatly extended by reducing the power consumption during the data transfer operation.

  In addition, when reflected wave transmission is used for the wireless communication function between the memory medium 110 and the wireless reader 102, the wireless unit 115 in the memory medium 110 is configured as a reflector, and is transmitted from the wireless reader 102 in units of pages, for example. It simply performs a simple data transmission operation of returning the requested data as a modulated reflected wave with respect to the received radio wave.

  In this way, the data transmission operation in which the reflector modulates the reflected wave of the received radio wave based on the transmission data, that is, the data is backscattered, can be realized under the control of the wireless reader 102 side, Control of the digital camera 101 as a host device that accommodates the media 110 is not involved. In other words, the digital camera 101 with the memory medium 110 with the wireless unit 115 is completely free from problems such as device driver installation and update accompanying a communication protocol version change.

  Hereinafter, the configuration of the wireless unit 115 on the memory medium 110 with wireless communication function and the wireless reading device 200 (102) when the reflected wave transmission system is applied will be described in detail.

  FIG. 4 shows the configuration of the wireless unit 115 on the memory media 110 side with the wireless communication function. The illustrated wireless unit 115 includes an antenna 111, an antenna switch 410, an antenna load 411, a band pass filter 412, and an ASK detection unit 413. In the present embodiment, a 2.4 GHz band called ISM is used as the frequency of the radio wave.

  For example, when image data stored in the flash memory 114 is transferred, the transmission unit 116 of the wireless unit 115 operates as a reflector in the reflected wave transmission system. That is, when the image data read from the flash memory 114 is received by the memory / communication control unit 113, the antenna switch 410 connected to the antenna 111 is turned on / off according to the bit image of the data. For example, the antenna switch 410 is turned on when the data is 1, and is turned off when the data is 0.

  As illustrated, when the antenna switch 410 is on, the antenna 111 is terminated with an antenna load 411 of 50Ω, and when the antenna switch 410 is off, the antenna 111 is open. In this operation, the radio wave (unmodulated carrier) arriving from the wireless reader 102 (reflected wave reader) as the transfer destination behaves as a terminal when it is on and as a reflection when it is off. The image data can be read by detecting the reflection of the transmission radio wave. That is, the image data is basically transmitted as a reflected wave of the radio wave from the transfer destination caused by the fluctuation of the antenna load impedance accompanying the on / off operation of the antenna switch 410. The reflected wave signal from the wireless unit 115 is equivalent to an ASK modulated wave. However, in the reflected wave transmission system, it is also possible to apply a PSK or FSK modulation system in addition to ASK modulation (described later).

  The antenna switch 410 is generally composed of a gallium arsenide IC, and its power consumption is several tens of μW or less. Therefore, according to the communication method described above, wireless image transmission with ultra-low consumption can be realized.

  The band pass filter (BPF) 412 and the ASK detection unit 413 are used when receiving an ASK-modulated delivery confirmation signal from the transfer destination, but these two blocks are used for one-way transmission without confirming transmission. If there is, it becomes unnecessary. On the other hand, when delivery confirmation is performed, the control is performed by the memory / communication control unit 113.

  The band pass filter (BPF) 412 is used for the purpose of passing a frequency in the 2.4 GHz band and attenuating other frequency bands. The power consumption of the ASK detection unit 413 required when confirming delivery can be realized with 30 mW or less.

  Therefore, the average power when transmitting data such as image data in the wireless communication apparatus shown in FIG. 4 is 10 mW or less in the case of the delivery confirmation method, and data transmission is possible at several tens of μW in the one-way transmission. This is an overwhelming performance difference compared to the average power consumption of a general wireless LAN. Further, the module area constituting the wireless unit 115 can be extremely reduced as compared with the case where a wireless LAN is employed.

  FIG. 5 schematically illustrates a hardware configuration of the wireless reading apparatus 102 when reflected wave transmission is applied as a wireless communication interface.

  The wireless reader 102 is configured as a reflected wave reader for reading a reflected wave signal from the reflector. Since the image data from the memory module 110 with a wireless function is transmitted as a reflected wave, it is necessary to transmit an unmodulated carrier for generating a reflected wave from the wireless reader 102. The wireless reader 102 includes a 2.4 GHz band antenna 201, a circulator 502 instead of an antenna switch, a receiver 503 including a quadrature detector 504 and an AGC amplifier 505, and a transmitter including a mixer 508 and a power amplifier 507. 506 and a frequency synthesizer 509. The configurations and operations of the communication control unit 205, the JPEG decoder 206, the infrared light receiving unit 209, and the display unit 207 are the same as described above, and thus the description thereof is omitted here.

  Transmission of an unmodulated carrier from the transmission unit 506 is realized by applying a certain DC voltage from the communication control unit 205 to the mixer 508. The frequency of the unmodulated carrier to be transmitted is determined by the frequency of the frequency synthesizer controlled by the communication control unit 205. In the present embodiment, a 2.4 GHz band called ISM is used. The unmodulated carrier output from the mixer 508 is amplified to a predetermined level by the power amplifier 507 and is transmitted from the antenna 201 via the circulator 502.

  The reflected wave signal from the memory module 110 with the wireless communication function has the same frequency as that transmitted from the wireless reader 200. This reflected wave signal is received by the antenna 201 and input to the above-described receiving unit 503 via the circulator 502. That is, since the same local frequency as the transmission is input to the quadrature detection unit 504, the ASK modulated wave multiplied by the radio unit 115 appears in the output of the quadrature detection unit 504. However, since the received signal has a phase different from that of the local signal, a modulation signal corresponding to the phase difference appears in the I-axis signal and the Q-axis signal.

  In the AGC amplifier unit 505, the gain is controlled to an optimum value, and the output signal is passed to the communication control unit 205. The communication control unit 205 demodulates the digital data from the I-axis and Q-axis signals, and correct data is decoded by the coder 206 using JPEG. Thereafter, the decoded data is further converted into an analog video signal, for example, and is output to the television 106 via the cable 105. Alternatively, data obtained by rendering an image is output to a printer (not shown) and printed out on paper.

  When confirming delivery of data from the memory module 110 with the wireless communication function, the communication control unit 205 makes an acknowledgment ACK (Acknowledgement) if the received packet data is correct, and a negative NACK (acknowledgement) if it is wrong. (Negative Acknowledgment) digital data is transferred to the mixer 508 and subjected to ASK modulation. Whether the data is correct or not is determined by a CRC (Cyclic Redundancy Check) code added to the image data packet.

  FIG. 6 shows a control sequence for performing wireless data communication by reflected wave transmission between the wireless unit 115 of the memory module 110 with wireless communication function shown in FIG. 4 and the wireless reader 102 shown in FIG. Yes. However, in the illustrated example, it is assumed that delivery confirmation is performed between both devices. Hereinafter, this control sequence will be described.

(Step 1)
In the memory module 110 with the wireless communication function, the control signal 103 is received from the wireless reader 102 or the wired communication mode via the connector unit 112 is set to the wireless communication mode according to other procedures.

(Step 2)
Similarly, the wireless reader 102 is set to a data reception waiting mode in response to receiving an infrared command from the infrared remote controller 108 or according to other procedures.

(Step 3)
The wireless reader 102 transmits an unmodulated carrier so as to receive the reflected wave signal from the memory module 110 with the wireless communication function.

(Step 4)
The wireless unit 115 of the memory module 110 with the wireless communication function that has received the unmodulated carrier makes a data transmission request using the reflected wave.

(Step 5)
The wireless reader 102 that has received the data transmission request transmits a transmission permission by ASK modulation.

(Step 6)
The wireless reader 102 transmits a non-modulated carrier in order to receive data requested to be transmitted (for example, image data or transmission data / file list data).

(Step 7)
The wireless unit 115 of the memory module 110 with the wireless communication function that has received the unmodulated carrier transmits the packetized data by using the modulation of the reflected wave.

(Step 8)
If the received packet data is correct, the wireless reader 102 sends an acknowledgment ACK (Acknowledgement) by ASK modulation. If it is wrong, a negative acknowledgment NACK (Negative Acknowledgment) is transmitted. Here, whether the data is correct or incorrect can be determined by a CRC (Cyclic Redundancy Check) code added to the data packet.

  When the wireless reader 102 transmits an acknowledgment signal of ACK or NACK, a command for the memory module 110 with the wireless communication function can be included in the same signal.

  Thereafter, the processing of step 6 to step 8 is repeatedly executed until the end of data.

  In the communication sequence described above, since it is image transfer, bi-directional communication is used to confirm data delivery. However, when transferring streaming data such as a video camera, transmission in one direction may be performed. In this case, the ASK-modulated delivery confirmation signal from the wireless reader 102 is not required, so that reception by the wireless communication function-equipped memory module 110 is also unnecessary, and further reduction in power consumption can be realized.

  FIG. 7 shows an operation example of the reflected wave transmission system employing the TDD (Time Division Multiplexing) method. In this system, since reflection is used, the reflected wave reader (in this case, the wireless reader 102) repeats a state of transmitting a non-modulated carrier and receiving a reflected wave, and a state of transmitting data using a modulated wave by itself. On the reflector (in this case, memory module 110 with wireless communication function) side, backscatter transmission is performed as a reflected wave with data on an unmodulated carrier, and then a modulated wave is received from the reflected wave reader side. Repeat with the state.

  The reflected wave transmission system is an asymmetric transmission system in which the upward transmission rate from the reflector to the reflected wave reader is faster than the downward transmission rate from the reflected wave reader to the reflector. Therefore, as described above, in the communication mode in which the transmission ratio from the memory module 110 with the wireless communication function, that is, the reflector side occupies most of the communication, the transmission efficiency is increased and the low power consumption data transmission is realized. Can do.

C. Address storage function of memory media In an operation of searching for an image in a memory space in which a plurality of image files are stored, it is possible to estimate that the last accessed address is the file that the user wants to see most. This is because the user has a habit of transferring data after confirming (i.e., previewing) the file he / she wants to see most.

  Therefore, the memory medium 110 may further include an address storage unit that stores address information in the flash memory 114 accessed last. In such a case, the digital camera 101 or wireless reader 102 serving as the data transfer destination acquires address information from the address storage unit, and then specifies the last accessed file based on the acquired address information. By doing so, it is possible to request the memory medium 110 for data constituting a desired file. Alternatively, the user can designate data to be transferred to the wireless reading device 102 by browsing the file most desired to be viewed last when transferring data with the digital camera 101.

  FIG. 11 schematically shows the configuration of the wireless transmission system in this case. As in the embodiment shown in FIG. 1, this system includes a digital camera 101, a memory medium 110 with a wireless communication function, a wireless reader 102, a television 106, and an infrared remote controller 108.

  The memory medium 110 with the wireless communication function is accommodated in a dedicated memory slot or the like (not shown) of the digital camera 101 and connected to the connector unit 112. The connector unit 112 constitutes a wired communication interface between the memory medium 110 with a wireless communication function and the digital camera 101. For example, the standard interface specification such as MEMORYSTICK (registered trademark), PC card, or USB is used. It shall comply.

  From the digital camera 101 side, it is possible to access the flash memory 114 in the memory medium 110 with the wireless communication function via the connector unit 112, and to write the captured image into the flash memory 114, Data such as an image stored in the memory 114 can be read. The memory medium 110 with the wireless communication function is supplied with driving power from the digital camera 101 via the connector unit 112.

  The memory medium 110 with a wireless communication function includes a wireless unit 115 as a wireless communication interface with the wireless reader 102. The wireless unit 115 includes a transmission unit 116 and a reception unit 117, and can perform wireless transmission with the wireless reading apparatus 102 using reflected wave transmission. For example, the control signal 103 is wirelessly transmitted from the wireless reader 102. In response to this, a response signal 104 such as JPEG image data is wirelessly transmitted from the memory medium 110 with a wireless communication function in the digital camera 101.

  The wireless reader 102 is connected to an external video input terminal of the television 106 via a video cable 105. The wireless reader 102 can output the image data acquired from the digital camera 101 to the external video input terminal of the television 106 via the video cable 105.

  The television 106 and the wireless reading device 102 include infrared light receiving units 107 and 109, respectively, receive infrared commands and execute device operations in accordance with the commands. Further, the infrared remote controller 108 can give a control command for the television 106 or the wireless reader 102 to the infrared light receiving unit 107 as a control signal 118 made of infrared rays. The user uses the infrared remote controller 108 to instruct the wireless reader 102 to read image data from the memory medium 110 with a wireless communication function in the digital camera 101 and output video to the television 106. The television 106 can be instructed to display and output image data input from the cable 105 via a line.

  The memory medium 110 with wireless communication function includes a memory / communication control unit 113, a connector part 112, an antenna 111, in addition to the flash memory 114 that is the substance of the memory space in the memory medium 110 with wireless communication function, A wireless unit 115 is provided.

  The memory medium 110 with a wireless communication function is wired to the digital camera 101 via the connector unit 112. In addition to performing data transmission via the connector unit 112, driving power is supplied from the digital camera 101.

  The memory / communication control unit 113 controls the wireless communication operation in the wireless unit 115 in addition to the memory access to the flash memory 114. Specifically, the memory / communication control unit 113 controls an operation of transmitting data read from the flash memory 114 from the wireless unit 115. In addition, the memory / communication control unit 113 includes an address storage unit 113A that stores address information of the last access to the flash memory 114. The address information includes a physical block number and a page number to be accessed in the flash memory 114.

  The wireless communication operation for wirelessly transmitting data read from the flash memory 114 by the memory / communication control unit 113 is independent of the digital camera 101 loaded with the memory medium 110 and is wirelessly connected to the wireless reader 102. It can be performed by the control operation by. Therefore, the data read from the flash memory 114 can be wirelessly transmitted between the memory medium 110 and the wireless reader 102 without mounting a device driver for communication control on the digital camera 101 side.

  In the present invention, data communication is performed between the memory medium 110 and the wireless reader 102 via the wireless communication means, and between the memory medium 110 and the digital camera 101 via the wired communication means. Assume a system. Here, when data is transferred between two devices, generally, a file to be transmitted and a file transfer destination are designated in the data transfer source device, and then the file transfer is performed. For example, when an image captured by the digital camera 101 is transferred to a PC, a memory medium 110 that stores the captured image is connected to the PC, a file to be transferred is designated, and a transfer process to the PC is performed. When the memory medium 110 and the PC are connected by the above-described reflected wave transmission path, the user needs to perform both an operation for adjusting the directivity between both devices and an operation for designating a transfer file. .

  However, when a transfer file is designated by a user operation, every time the file is sent, the user needs to adjust the directivity of the wireless unit 115 in the memory medium 110 to the direction of the wireless reader of the PC that is the data transfer destination. To be annoying.

  On the other hand, in the embodiment shown in FIG. 11, the memory / communication control unit 113 that controls the access operation to the flash memory 114 and the transfer operation of the accessed data in the memory medium 110 is accessed last. An address storage unit 113A for storing address information in the flash memory 114 is provided. The last accessed address can be assumed to be the file that the user wants to see most. This is because the user has a habit of transferring data after confirming (i.e., previewing) the file he / she wants to see most. Alternatively, the user may designate the transfer file by accessing the file he / she wants to see most last during data transfer.

  A data transfer destination such as the wireless reader 102 or the digital camera 101 obtains address information from the address storage unit 113A, and then specifies the last accessed file based on the obtained address information. Data constituting the file to be processed can be requested to the memory medium 110 via the memory / communication control unit 113.

  The control sequence in the wireless transmission system according to the present embodiment is similar to the operation sequence shown in FIG.

  On the digital camera 101, the captured image is written into the flash memory 114 each time an image is captured. Further, when displaying a captured image on a viewer (not shown), data such as an image stored in the flash memory 114 is read out.

  Here, the user operates the infrared remote controller 108 when he / she wants to watch an image captured by the digital camera 101 on the television 106.

  The infrared remote controller 108 sends a video switching signal to the television 106. In response to the infrared command, the television 106 changes from the received image display mode to the external video input mode.

  Subsequently, the infrared remote controller 108 sends a display request signal to the wireless reader 102. In response to this, the wireless reader 102 sends a transfer request signal to the memory medium 110 with the wireless communication function.

  When the memory / communication control unit 113 in the memory medium 110 with the wireless communication function receives the transfer request signal, the memory / communication control unit 113 connects the connector unit 112 from the digital camera 101 side in order to avoid contention for access to the flash memory 114. Access to the flash memory 114 via is prohibited. Then, the memory / communication control unit 113 reads the image data 104 from the flash memory 114 and sends it to the wireless reader 102.

  When the wireless reader 102 receives the image data by wireless communication, the wireless reader 102 demodulates the received image data, further performs JPEG decoding and conversion into an analog video signal, and then outputs the video data to the television 106 via the cable 105.

  For example, the following two methods can be used to designate which of the files stored in the flash memory 114 should be transferred.

(1) A file name is designated from the wireless reader 102, the file structure in the flash memory 114 is recognized on the memory medium 110 side, and the designated file is transferred. That is, the memory medium 110 has a FAT (File Allocation Table) and manages files.
(2) The wireless reader 102 recognizes the file structure in the flash memory 114 in the memory medium 110, designates the block number and page number of the flash memory 114 in the memory medium 110, and transfers the file. . That is, the wireless reader 102 has a FAT and manages files.

  In any file designation method, when a transfer file is designated by a user operation, every time a file is sent, the user needs to adjust the directivity of the wireless unit 115 in the memory medium 110 to the direction of the wireless reader 102. It's very annoying. On the other hand, in the apparatus configuration shown in FIG. 11, the user can use the address information in the last accessed flash memory 114 held in the address storage unit 113 </ b> A in the memory / communication control unit 113. You can estimate the file you want to see the most. Alternatively, the user may designate the transfer data by accessing the most desired file at the end with the digital camera 101 during data transfer.

  The wireless reading device 102 or the memory / communication control unit 113 acquires the address information from the address storage unit 113A, and then specifies the last accessed file based on the acquired address information, and performs the designation operation by the user. File transfer can be performed without intervention.

  Of course, a desired file may not always be specified from the last accessed address stored in the address storage unit 113A. In such a case, as described above, the information request signal may be transferred to the memory medium 110 with the wireless communication function. An image information signal describing a list of image files is returned from the memory medium 110 with the wireless communication function. Then, a list of files is displayed on the television 106, and the user can make a display request again from the file list.

  Here, the latter file designation method, that is, a mechanism of wireless communication control in the case where the wireless reader 102 has a FAT and manages files will be described. In this case, the wireless reader 102 recognizes the file configuration in the flash memory 114 in the memory medium 110, designates the block number and page number of the flash memory 114 in the memory medium 110, and transfers the file. .

  FIG. 12 schematically shows a functional configuration of the communication control unit 205 in the wireless reading apparatus 102 (200). As illustrated, the communication control unit 205 is roughly divided into a communication control function unit and a host function unit.

  The communication control function unit includes a modulation function unit 1201 that performs modulation processing of a transmission signal in reflected wave transmission, a demodulation function unit 1202 that performs demodulation processing of a received signal, and connection and disconnection of reflected wave communication according to a predetermined communication protocol. The protocol control unit 1203 performs protocol control.

  The host function unit includes a data control unit 1205, a file control unit 1206, and a management unit 1207, in addition to the communication control unit 1204 that controls communication operations in the communication control function unit.

  The data control unit 1205 is a driver control unit that performs data read and write operations on the flash memory 114 with a minimum physical access unit (generally 512 bytes) called a sector or page. . The file control unit 1206 corresponds to a FAT file system, and performs reading and writing operations of file data, that is, data in units of files. The management unit 1207 provides a user interface in the host function unit such as command input from the user, and comprehensively manages the operation of the entire host function unit. The management unit 1207 basically handles data in file units.

  Data transmitted from the host function unit is modulated by the modulation function unit 1201. The modulated signal is then transmitted to the memory medium 110 on an unmodulated carrier. In general, ASK is used for the downlink from the host device in consideration of the ease of detection on the memory medium 110 side.

  FIG. 13 schematically shows a functional configuration of the memory / communication control unit 113 in the memory medium 110. As shown in the figure, the memory / communication control unit 113 is roughly divided into a communication control function unit and a memory access function unit.

  The communication control function unit includes a modulation function unit 1301 that performs transmission signal modulation processing in reflected wave transmission, a demodulation function unit 1302 that performs demodulation processing of a received signal, and connection and disconnection of reflected wave communication according to a predetermined communication protocol. The protocol control unit 1303 performs protocol control. The reception signal received by the reception unit 117 in the wireless unit 115 is demodulated by the demodulation function unit 1302 and received by the memory access function unit.

  The data read from the flash memory 114 by the memory access function unit 1304 is modulated by the modulation function unit 1301 of the communication control function unit. The modulated signal is placed on a reflected wave obtained by detecting a non-modulated carrier in the transmitting unit 116 in the wireless unit 115 and transmitted backscatter to the wireless reading apparatus 102. The wireless unit of the wireless reader 102 receives the reflected wave signal and obtains a demodulated signal. The demodulated signal is demodulated by the demodulation function unit 1202 and received by the host function unit.

  Although not shown in FIG. 13, the memory access function unit 1304 includes an address storage unit 113 </ b> A that stores the address accessed last in the flash memory 114.

  Between the data control unit 1205 on the wireless reader 102 (200) side and the memory access function unit 1304 on the memory medium 110 side, the read and write access operations for the physical data on the flash memory 114 are controlled. . The file control unit 1206 on the wireless reader 102 (200) side performs logical file system control for constructing the data read and written by the data control unit 1205 as file data.

  Next, file system control performed mainly by the host function unit on the wireless reading apparatus 102 side will be described. FIG. 14 shows a configuration example of the physical storage area 700 and the file data 800 of the flash memory 114 when a NAND flash memory is assumed as the flash memory 114.

  First, the physical address space will be described. The physical access unit of the storage area 700 is a 512-byte unit called “page”. However, when the storage device is constituted by a hard disk instead of a flash memory, the physical access unit is called a “sector”.

  In addition, the storage area 700 constitutes a unit called “block” in a group of a plurality of pages (generally 32 pages). The storage area 700 is physically divided into block units and is address-managed. However, when the storage device is constituted by a hard disk instead of a flash memory, a group of a predetermined number of sectors constitutes a “cluster”, and address management is performed in cluster units.

  Next, the logical address space will be described. The storage area 700 is logically divided into blocks by a boot block 71, a FAT block 72, a directory area 73, and a data area 74. The boot block 71 stores information related to the entire storage area. A FAT (File Allocation Table) block 72 stores address arrangement information for each block constituting the file data (for example, http://home.impress.co.jp/magazine/dosvpr/q-a/). 0007 / qa0007_2.htm /). The directory area 73 stores directory information of all file data and head address information of each file data. The data area 74 stores block data constituting file data.

  In the host function unit that makes an access request to file data, the file control unit 1206 acquires the boot block 71 from, for example, the address storage unit 113A, and obtains information in the directory area 73. Next, the head address information of the desired file data is obtained from the directory area 73. Next, the address information of the blocks constituting the file data is obtained from the FAT block 72. Then, the data control unit 132 sequentially obtains block data constituting the file data and concatenates them to obtain the file data 800.

  As described above, the wireless reader 102 (200) processes file data in units of block data.

  FIG. 15 shows a processing sequence for reading and accessing file data in block data units from the host function unit on the wireless reader 102 (200) side to the memory access function unit 1304 on the memory medium 110 side. ing.

  The management unit 1207 of the host function unit issues a connection request to the communication control unit 1204 (1501). The communication control unit 1204 is a reflected wave transmission path between the communication function units 1201 to 1203 and the wireless unit, and the memory access control unit 1304 via the wireless unit 115 and the communication function units 1301 to 1303 of the memory medium 110. Establish a connection in (1502). Then, a connection response is returned from the communication control unit 1204 to the management unit 1207 (1503).

  On the wireless reader 102 (200) side, in order to access a desired file stored in the memory medium 110 in page or sector units, logical block address information and physical block address are used. It is necessary to know the correspondence with information. Each page in the flash memory 114 includes logical address information related to data assigned to the page (described later). Accordingly, the wireless reader 102 (200) requests the memory medium 110 for logical address information regarding each page or sector, and based on the received logical address information, creates an address conversion table regarding blocks constituting each file. Can be generated.

  Subsequently, the management unit 1207 requests the file control unit 1206 to read the designated file data (file read). For example, the file can be specified based on the address information read from the address storage unit 113A on the memory medium 110 side, but the file can also be specified by other methods such as an instruction from the management unit 1207. .

  In response to the file designation, the file control unit 1206 performs a block data read operation from the memory medium 110 based on the file system control described above.

  Access to the flash memory 114 in the memory medium 110 is performed in units of pages (described above). In the present embodiment, the file control unit 1206 acquires data in units of pages, which are physical access units to the flash memory 114, in order to read out file data under the initiative of the wireless reader 102 (200). To do. For this purpose, the file control unit 1206 issues a page read request via the data control unit 1205 (1504), and obtains a page read response from the memory access function unit 1304 that has acquired the page data (1505). . The page number of the requested page can be obtained from the address conversion table described above. A transaction including a page read request 1504 and a page read response 1505 is repeatedly executed until page data for one file is acquired.

  In this way, when a data request occurs in units of files, the wireless reader 102 (200) does not request data from the memory medium 110 in units of files, but requests data for each page constituting the file. Then, the data request for the entire file is realized by sequentially transmitting data in units of pages to the flash memory 114 via the reflected wave transmission path. The data acquired in units of pages is reconstructed into the original file by the file control unit 1206. In this case, data control for the storage area in the memory medium 110 is performed by the memory / communication control unit 113 via the reflected wave transmission path, but from the wireless reader 102 (200) to the flash memory 114. This is equivalent to direct read / write control of file data, and control by the host device that accommodates the memory medium 110 is not involved.

  FIG. 16 shows a configuration example of a physical format and a logical format of the flash memory 114 as a storage device in the memory medium 110.

  Page data, which is a physical access unit of the flash memory 114, is composed of a total of 528 bytes including a 512-byte data area and a 16-byte extended data area. Therefore, the size of the page buffer used for accessing the flash memory 114 is 528 bytes.

  The data area corresponds to the payload. The extended data area includes an overwrite flag, a management flag, a logical address of a physical block, a format reserve, and ECC (Error Correction Code) for error detection / correction of page data. Among these, the logical address stores the logical address to which the corresponding physical page is allocated in the virtual space of the file system.

  When the wireless reader 102 (200) establishes a connection on the reflected wave transmission path with the memory medium 110 with the wireless unit 115 made of a reflector, the allocation information in the flash memory 114 is unknown. Therefore, the wireless reader 102 (200) makes a request to read the extended data area when establishing a connection, and acquires the logical address information of each page, thereby generating an address conversion table.

  On the flash memory 114, one block is formed for every 32 pages (= 16 kilobytes). Each block is assigned a block number. A page number is assigned to each page in the block. Therefore, a specific page can be requested from the storage area of the flash memory 114 by specifying a block number and a page number. Further, a segment is formed for every 512 blocks (= 8 megabytes), and a segment number is assigned to each segment.

  The wireless reader 102 (200) performs physical access control to the memory media 110 with a reflector. 512 bytes of page data and 16 bytes of extended data corresponding to the physical block number and page number added to the control command are read or written via the page buffer.

  In Japanese Patent Application No. 2004-334005 already assigned to the present applicant, recording data constituting a file is stored in a page unit via a reflected wave transmission path to a memory medium having a reflector. The communication system required in the above is described.

  As described above, since the memory medium 110 holds the last accessed address, for example, the wireless reader 102 displays an image that the user last played back on the digital camera 101 loaded with the memory medium 110. On the (200) side, it can be read without a file designation operation by the user.

  FIG. 17 shows a control sequence in the case of transferring an image viewed last by the digital camera 101. The address information (ie, the block number and page number of the last read file in the flash memory 114) relating to the file that was last played back is stored in the address storage unit 113A in the memory / communication control unit 113 of the memory medium 110. Is remembered. This address information is updated every time the user plays back and views the image.

  The illustrated control sequence is between the digital camera 101 and the memory medium 110 with wireless communication function, the wireless reader 102, the television or other monitor display 106, and the infrared remote controller 108 operated by the user. Consists of communication operations.

  On the digital camera 101, the captured image is written into the flash memory 114 each time an image is captured. Thereafter, the user performs playback display on the digital camera 101 of the captured image to be displayed on the television 106.

  At this time, the memory / communication control unit 113 of the memory medium 110 stores the address information (block number and page number) of the last read file of the flash memory 114 in the internal address storage unit 113A.

  Here, the user operates the infrared remote controller 108 to view the image displayed on the digital camera 101 on the television 106.

  The infrared remote controller 108 sends a video switching signal to the television 106. In response to the infrared command, the television 106 changes from the received image display mode to the external video input mode.

  Subsequently, the infrared remote controller 108 sends a display request signal to the wireless reader 102. In response to this, the wireless reader 102 sends a final read information request signal to the memory medium 110 with the wireless communication function.

  When the final read information request signal is received, the memory medium 110 with the wireless communication function prohibits access from the digital camera 101 via the connector unit 112 in order to avoid contention for access to the flash memory 114. . Then, the address information (that is, the block number and page number) of the last read file stored in the internal address storage unit 113A is read and sent to the wireless reading apparatus 102.

  The wireless reader 102 searches the address conversion table in the memory medium 110 based on the received final read information, and identifies the final read file. Then, a transfer request for the target file is made, and JPEG image data is read out. At this time, when an access operation from the wireless reader 102 to the flash memory 114 is performed in units of pages, a transaction including a page read request and a page read response is performed as many times as the number of pages corresponding to the requested image file. It will be executed repeatedly (see above and FIG. 15).

  When the wireless reading apparatus 102 receives the target image data by wireless communication, the wireless reading apparatus 102 demodulates the received image data, further performs JPEG decoding and conversion into an analog video signal, and then outputs the video to the television 106 via the cable 105.

  In this way, the image played back on the display unit of the digital camera 101 can be read out from the wireless reading device 102, and the operation of selecting an image on the wireless reading device 102 side becomes unnecessary, improving convenience. To do.

D. Corresponding to the power saving function on the host device side As described above, the memory medium 110 with the wireless communication function is supplied with the driving power from the digital camera 101 via the connector unit 112, and uses this supplied power. An access operation to the flash memory 114 by the memory / communication control unit 113 and a wireless communication operation by the wireless unit 115 are driven.

  On the other hand, the digital camera 101 as a host device has a power saving function for battery operation, and a timer for measuring the elapsed time since the last event occurred in the memory medium 110 accommodated in the memory slot. In response to the time-out, power supply via the connector unit 112 is stopped.

  Under such circumstances, there is a possibility that the timer will time out and power supply to the memory card will be stopped during the period during which wireless transmission is performed in the memory medium 110 outside the control of the digital camera 101. There is. If the power of the memory medium 110 in communication is cut off during the communication, the communication is forced to be interrupted and cannot be restored thereafter.

  Therefore, in the present embodiment, a predetermined event is generated on the connector unit 112 before the timer on the host device side times out to avoid stopping the power supply to the memory medium 110.

  For example, the connector unit 112 includes an insertion / removal detection signal for detecting the insertion / removal of the memory medium 110 from the host device side. The digital camera 101 as the host device is configured to stop power supply when detecting the removal state of the memory medium 110 on the insertion / removal detection signal, but to start power supply in the insertion state. In such a case, on the memory media 110 side, the wireless communication operation by the wireless unit 115 is temporarily interrupted before the power saving timer set in the digital camera 101 times out, and the wireless communication operation is When temporarily interrupted, a pseudo disconnection state is formed on the insertion / extraction detection signal to temporarily stop power supply from the digital camera 101, and then return to the insertion state to resume power supply from the digital camera 101. By doing so, it is possible to avoid stopping the power supply to the memory medium 110.

  FIG. 18 shows a mechanism for avoiding power supply interruption from the digital camera 101 to the memory medium 110.

In the figure, reference numeral 131 denotes a power supply line V _ccm that supplies driving power from the digital camera 101 to the memory medium 110 with a wireless communication function.

  Reference numeral 132 is an insertion / removal detection signal INS for detecting insertion / removal of the memory medium 110 into / from a memory slot.

  Reference numeral 133 is a ground line GND, and is connected to the ground inside the digital camera 101 and the memory medium 110.

The insertion / extraction detection signal INS is pulled up by the power supply line V _ccm through a pull-up resistor R1 (100 kΩ) indicated by reference numeral 134 in the digital camera 101. Further, the insertion / extraction detection signal INS is connected to the ground line GDN through a pull-down resistor R2 (1 kΩ) indicated by reference numeral 135 in the memory medium. Then, R1 >> R2 is selected.

In such a case, the signal level of the insertion / extraction detection signal INS is pulled up to the high level by the power supply line V _ccm when the memory medium 110 is not inserted, and becomes the ground line when the memory medium is inserted. Pulled down by GND and goes low. Therefore, on the digital camera 101 side, the insertion / extraction of the memory medium 110 can be detected by monitoring the signal level of the insertion / extraction detection signal INS.

On the digital camera 101 side, an event occurs at the end on the memory medium 110 side via the connector part 112 and an insertion / extraction detection function part that detects the insertion / extraction of the memory medium 110 based on the signal level of the insertion / extraction detection signal INS. And a power control function unit for stopping power supply to the memory medium 110 via the power supply line V _ccm in response to a timer timeout.

  In addition, the memory / communication control unit 113 in the memory medium 110 includes a timer function unit that measures the elapsed time from the start of wireless data communication in the wireless unit 115 without the digital camera 101, and the elapsed time. And an INS control function unit for operating the signal level of the insertion / extraction detection signal INS according to the above. The INS control function unit can form a pseudo removal state and insertion state for the digital camera 101 by manipulating the signal level of the insertion / removal detection signal INS.

Hereinafter, a processing operation by the memory / communication control unit 113 when wireless data communication is performed by the wireless unit 115 in a state where the memory medium 110 is inserted into the digital camera 101 and the power source V _ccm is supplied. This will be described with reference to FIG.

  When wireless data communication by the wireless unit 115 is started, the memory / communication control unit 113 activates its timer function unit and measures the elapsed time from the start. At this time, the INS output from the memory / communication control unit 113 is at a low level, and the digital camera 101 can correctly recognize the insertion state of the memory medium 110.

The timer function unit of the memory / communication control unit 113 is set to be shorter than the timer (for example, 3 minutes) for stopping the power supply to the memory medium 110 via the power supply line V _ccm on the digital camera 101 side. There are two timeout values t1 and t2 (where t1 <t2).

  First, when t1 expires, the memory / communication control unit 113 sends a communication interruption notification to the wireless reading apparatus 102 side, and temporarily interrupts the wireless communication operation.

Next, when t2 expires, the memory / communication control unit 113 changes the signal level of the insertion / extraction detection signal INS to high. In response to detecting the high level of the insertion / extraction detection signal INS, the digital camera 101 side recognizes that the memory medium 110 has been removed, and therefore the power supply line at time t3 when a predetermined time has elapsed. Turn V _ccm off.

When power is not supplied from the power supply line V _ccm , the memory / communication control unit 113 stops operating. As a result, since the insertion / extraction detection signal INS is connected to the grant via the pull-down resistor R2, its output is turned to a low level.

When the digital camera 101 detects that the signal level of the insertion / extraction detection signal INS has become low, the digital camera 101 artificially recognizes that the memory medium 110 has been inserted again, so that the memory medium 110 with a wireless communication function is provided at time t4. The power supply V _ccm is started to be supplied.

  Next, at time t5, the wireless reader 102 requests the memory / communication control unit 113 to reconnect communication, and in response, the memory medium 110 with wireless communication function resumes wireless communication operation. .

  By doing so, power to the memory medium 110 with the wireless communication function is temporarily turned off, but is turned on again, and communication can be temporarily interrupted and resumed.

E. Application of Multi-level Modulation Method to Reflected Wave Transmission Generally, a reflected wave transmission system employs a modulation method with a relatively low bit rate such as ASK (Amplitude Shift Keying). For example, signals 0 and 1 can be arranged in the signal space by manipulating load impedance such as on / off operation of the end of the directional antenna on the reflector side, and BPSK modulation can be easily realized. . However, these modulation methods have a problem in terms of transmission speed. On the other hand, for example, by providing multiple reflection paths with different phase differences and switching the reflection paths according to the transmission data, higher bit rate phase modulation methods such as BPSK, QPSK, and 8-phase PSK modulation are realized. can do.

  FIG. 8 shows a configuration example of a wireless unit that realizes the QPSK modulation method on the reflector side. The illustrated radio unit includes an antenna 1001, three phase shifters 1002, 1003, and 1004 connected in series to the antenna 1001, between the antenna 1001 and the phase shifter 1002, between the phase shifters 1002 and 1003, and the phase shifter 1003. And 1004, high-frequency switches 1005, 1006, and 1007, respectively.

The phase shifters 1002, 1003, and 1004 are constituted by lines such as strip lines that are λ / 8 with respect to the wavelength λ of the received radio wave 1008. At this time, the length L of the strip line is determined in consideration of the dielectric constant ε of the substrate and is given by the following equation. Where ε _eff is the effective dielectric constant of the substrate.

The signal transmission speed S on the substrate is expressed by the following equation. However, _C0 is the speed of light.

  The time required for the received radio wave to pass through each phase shifter is as shown in the following equation. Where T is the period of the received radio wave.

  Here, the received radio wave 1008 passes through each of the phase shifters 1002, 1003, and 1004 so that the phase is rotated by 360 / T × T / 8, and a difference of 45 degrees in one way and 90 degrees in a round trip is obtained. Each phase shifter 1002, 1003, 1004 is connected in series from the antenna 1001, and a short-circuit point is provided by a combination of on / off of the high-frequency switches 1005, 1006, 1007. Accordingly, the incoming received radio wave 1008 is reflected at the short-circuit point, but by providing a difference in the signal path that reciprocates according to the ON / OFF state of the switch, four kinds of phase differences are given to the reflected wave.

  When only the high frequency switch 1005 is turned on, reflection of the received radio wave occurs at point a in the figure. When only the high frequency switch 1006 is turned on, reflection of the received radio wave occurs at the point b in the figure, but compared with the phase of the reflected wave at the point a, the phase is 90 because it passes through the phase shifter 12. Will shift. When only the high frequency switch 17 is turned on, reflection occurs at the point c in the figure, but the phase is shifted by 180 degrees because it passes through the phase shifters 1002 and 1003 as compared with the phase of the reflected wave at the point a. Will do. In addition, when all the high frequency switches 1005 to 1007 are turned off, reflection occurs at the point d in the figure, but compared with the phase of the reflected wave at the point a, it passes through the phase shifters 1002, 1003 and 1004. The phase will shift 270 degrees. Therefore, by selectively turning on the high-frequency switches 1005, 1006, and 1007, reflected waves having four phases different from each other by 90 degrees can be created.

  When data transmission is performed, QPSK modulation is realized by dividing transmission data into two bits and assigning a phase corresponding to a combination of 0 and 1 of 2 bits. Specifically, the transmission data is divided into two bits. When 00, only the high frequency switch 15 is turned on. When 01, only the high frequency switch 1006 is turned on. When 11, the high frequency switch 1007 is turned on. When it is 10, it operates to turn off all the high frequency switches 15-17.

  In this way, it is possible to create reflected waves having four phases whose phases are different from each other by 90 degrees according to the value of data 2 bits, and (0,0), (0,1), Since four points (1, 0) and (1, 1) can be arranged, a QPSK-modulated reflected wave can be created.

  For example, WO 2005/36767, already assigned to the present applicant, discloses a backscatter communication system incorporating QPSK modulation processing.

  The present invention has been described in detail above with reference to specific embodiments. However, it is obvious that those skilled in the art can make modifications and substitutions of the embodiment without departing from the gist of the present invention.

  According to the present invention, driver software is installed on the digital camera side for communication control in order to transmit wirelessly from a memory card storing a photographed image of a digital camera or the like to a device such as a PC, a television, or a printer. You can do it.

  In addition, low power consumption can be realized by using reflected wave transmission as wireless transmission. In particular, low power consumption can be realized in a communication mode in which a transmission ratio occupies most of communication between devices that are relatively limited to a short distance. For example, compared with a wireless LAN, an extremely low-consumption image transmission can be realized with a mobile device. As a result, the battery life of the mobile device can be greatly increased.

  In addition, by using reflected wave transmission as the wireless transmission, the wireless transmission module of the mobile device on the data transmission side can easily realize cost reduction compared to the wireless LAN. In addition, since the wireless transmission module on the mobile side is not subject to a wireless station in the Radio Law, certification work such as conformity certification becomes unnecessary.

  In short, the present invention has been disclosed in the form of exemplification, and the description of the present specification should not be interpreted in a limited manner. In order to determine the gist of the present invention, the claims should be taken into consideration.

FIG. 1 is a diagram schematically showing a configuration of a wireless transmission system according to the first embodiment of the present invention. FIG. 2 is a diagram schematically showing a functional configuration of the wireless reader 102 that receives data from the memory medium 110 with the wireless communication function of FIG. FIG. 3 is a diagram showing a control sequence in the wireless transmission system according to the present invention. FIG. 4 is a diagram illustrating a configuration of the wireless unit 115 on the memory media 110 side with a wireless communication function using reflected wave transmission. FIG. 5 is a diagram schematically illustrating a hardware configuration of the wireless reading apparatus 102 using reflection for transmission. 6 is a diagram showing a control sequence for performing wireless transmission between the wireless unit 115 of the memory module 110 with the wireless communication function shown in FIG. 4 and the wireless reader 102 shown in FIG. FIG. 7 is a diagram illustrating an operation example of the reflected wave transmission system employing the TDD (Time Division Multiplexing) method. FIG. 8 is a diagram illustrating a configuration example of a radio unit that realizes the QPSK modulation method on the reflector side. FIG. 9 is a diagram illustrating an example of wireless image transmission. FIG. 10 is a diagram showing a configuration example of a memory card with a wireless communication function. FIG. 11 is a diagram schematically showing a configuration of a wireless transmission system according to the second embodiment of the present invention. FIG. 12 is a diagram schematically illustrating a functional configuration of the communication control unit 205 in the wireless reading apparatus 102. FIG. 13 is a diagram schematically showing a functional configuration of the memory / communication control unit 113 in the memory medium 110. FIG. 14 is a diagram showing a configuration example of the physical storage area 700 and the file data 800 of the flash memory 114. FIG. 15 shows a processing sequence for reading and accessing file data in block data units from the host function unit on the wireless reader 102 (200) side to the memory access function unit 1304 on the memory medium 110 side. FIG. FIG. 16 is a diagram showing a configuration example of the physical format and the logical format of the flash memory 114. FIG. 17 is a diagram illustrating a control sequence in the case of transferring an image viewed last by the digital camera 101. FIG. 18 is a diagram for explaining a mechanism for avoiding power supply interruption from the digital camera 101 to the memory medium 110. FIG. 19 shows processing operations performed by the memory / communication control unit 113 when wireless data communication is performed by the wireless unit 115 in a state where the memory medium 110 is inserted into the digital camera 101 and the power _Vccm is supplied. It is a figure for demonstrating.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 ... Digital camera 102,200 ... Wireless reader 105 ... Video cable 106 ... Television set 107, 109 ... Infrared light-receiving part 108 ... Infrared remote control 110 ... Memory media with a wireless communication function 111 ... Antenna 112 ... Connector part 113 ... Memory / Communication control unit 114 ... Flash memory 115 ... Radio unit 116 ... Transmission unit 117 ... Reception unit 120,207 ... Display unit 201 ... Antenna 202 ... Antenna switch 203 ... Reception unit 204 ... Transmission unit 205 ... Communication control unit 206 ... JPEG decoder 209 ... Infrared ray detector

Claims (2)

A memory card that is used in a host device,
Memory to store data,
Wired communication means detachably connected to the host device;
Wireless communication means for communicating with external devices via a wireless transmission path;
The power supply from the host device attached via the wired communication means performs an access operation from the external device via the wireless communication means to the memory, and according to the connection state of the external device in the wireless communication means. The memory and communication control means for controlling an access operation from the host device to the memory via the wired communication means ;
Comprising
In response to the time-out of a timer that counts the time elapsed since the last event occurred in the memory card connected via the wired communication means, the host device receives the time from the wired communication means. A power saving function for stopping power supply to the memory card;
During a period of performing wireless communication operation with the external device via the wireless communication means without intervention of the host device, a predetermined event is given to the host device via the wired communication means before the timer times out. Further comprising a power supply stop avoiding means for avoiding a power supply stop from the wired communication means to the memory card,
The wired communication means includes an insertion / removal detection signal for notifying the host device of insertion / removal of the memory card, and the host device stops power supply when detecting the removal state of the memory card on the insertion / removal detection signal. And is configured to start feeding in the inserted state,
The power supply stop avoiding means includes a communication interruption means for temporarily interrupting a wireless communication operation with the external device via the wireless communication means before the timer times out, and a wireless communication operation is temporarily interrupted. A power supply restarting unit that forms a pseudo disconnection state on the insertion / extraction detection signal to stop power supply from the host device and then returns to the insertion state and restarts power supply from the host device,
A memory card characterized by that. A memory that includes a memory for storing data, a wired communication unit that is detachably connected to the host device, and a wireless communication unit that performs a communication operation with an external device via a wireless transmission path, and is used by being attached to the host device A card control method,
Access operation to the memory from the external device via the wireless communication means, and access to the memory from the host device via the wired communication means according to a connection state of the external device in the wireless communication means A memory access control step for controlling the operation;
A wireless communication control step for controlling wireless communication operation by the wireless communication means;
Have
In the memory card, an access operation to the memory and a wireless communication operation by the wireless communication unit are performed by power supply from the host device mounted via the wired communication unit, and the host device is connected to the wired communication unit. The power supply to the memory card from the wired communication means is stopped in response to a timer that measures the elapsed time since the last event occurred in the memory card connected via It has a power function,
During a period of performing wireless communication operation with the external device via the wireless communication means without intervention of the host device, a predetermined event is given to the host device via the wired communication means before the timer times out. And a power supply stop avoidance step for avoiding a power supply stop from the wired communication means to the memory card,
The wired communication means includes an insertion / removal detection signal for notifying the host device of insertion / removal of the memory card, and the host device stops power supply when detecting the removal state of the memory card on the insertion / removal detection signal. And is configured to start feeding in the inserted state,
The power supply stop avoidance step includes:
A communication interruption step of temporarily interrupting a wireless communication operation with the external device via the wireless communication means before the timer times out;
When wireless communication operation is temporarily interrupted, a pseudo disconnection state is formed on the insertion / extraction detection signal to stop power supply from the host device, and then return to the insertion state to supply power from the host device. Having a step to resume,
A method for controlling a memory card.

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