US 20090321530 A1
A mother/daughter card non-volatile memory system includes a daughter card containing the memory and a mother card containing the memory controller and host interface circuits. The daughter memory card contains as little more than the memory cell array as is practical, in order to minimize its cost, and has an interface for connecting with a variety of mother controller cards having physical attributes and host interfaces according to a number of different published or proprietary memory card standards. Different types of memory cards may be used when the operating parameters of the memory are stored within it in a protected location, the mother card controller then reading these parameters and adapting its operation accordingly. A radio frequency antenna may be included on a surface of the card along with its electrical contacts, in order to provide a radio frequency identification function.
25. A method of obtaining and using a nonvolatile memory card, comprising:
obtaining at least one of the memory cards in a form attached to a larger storage card,
removing said memory card from the storage card and placing it in a device that generates data desired to be stored on the memory card,
storing such data on the memory card,
thereafter removing said at least one memory card from the device and re-attaching said memory card to the storage card, and
providing an appropriate surface on said storage card for noting the contents of the data stored on the memory card on a surface of the storage card.
26. The method according to
27. A hand-held substrate card, comprising:
a first area on a surface of the substrate card to which one or more electronic cards smaller than the substrate surface and each containing a non-volatile memory is attached,
a second area on the surface of the substrate that is treated to allow writing by pen or pencil, thereby enabling a user to note the data contents of said one or more memory cards attached thereto.
28. The substrate card of
29. The substrate card of
58. The substrate card of
59. The substrate card of
This invention relates generally to the use and structure of removable electronic circuit cards having different mechanical and/or electrical interfaces, particularly those including mass non-volatile integrated circuit memory.
Electronic circuit cards, including non-volatile memory cards, have been commercially implemented according to a number of well-known standards. Memory cards are used with personal computers, cellular telephones, personal digital assistants, digital cameras, portable audio players and other host electronic devices for the storage of large amounts of data. Such cards usually contain a non-volatile semiconductor memory cell array along with a controller that controls operation of the memory cell array and interfaces with a host to which the card connected. Several of the same type of card may be interchanged in a host card slot designed to accept that type of card. However, the development of the many electronic card standards has created different types of cards that are incompatible with each other in various degrees. A card made according to one standard is usually not useable with a host designed to operate with a card of another standard.
One such standard, the PC Card Standard, provides specifications for three types of PC Cards. Originally released in 1990, the PC Card Standard now contemplates three forms of a rectangular card measuring 85.6 mm. by 54.0 mm., having thicknesses of 3.3 mm. (Type I), 5.0 mm. (Type II) and 10.5 mm. (Type III). An electrical connector, which engages pins of a slot in which the card is removably inserted, is provided along a narrow edge of the card. PC Card slots are included in current notebook personal computers, as well as in other host equipment, particularly portable devices. The PC Card Standard is a product of the Personal Computer Memory Card International Association (PCMCIA). The latest release of the PC Card Standard from the PCMCIA is dated February 1995, which standard is incorporated herein by this reference.
In 1994, SanDisk Corporation introduced the CompactFlash™ card (CF™ card) that is functionally compatible with the PC Card but is much smaller. The CF™ card is rectangularly shaped with dimensions of 43 mm. by 36 mm. and a thickness of 3.3 mm., and has a female pin connector along one edge. The CF™ card is widely used with cameras for the storage of video data. A passive adapter card is available, in which the CF™ card fits, that then can be inserted into a PC Card slot of a host computer or other device. The controller within the CF™ card operates with the card's flash memory to provide an ATA interface at its connector. That is, a host with which a CF™ card is connected interfaces with the card as if it is a disk drive. Specifications for the card have been developed by the CompactFlash Association, a current version of these specifications being 1.4, which standard is incorporated herein by this reference.
The SmartMedia™ card is about one-third the size of a PC Card, having dimensions of 45.0 mm. by 37.0 mm. and is very thin at only 0.76 mm. thick. Contacts are provided in a defined pattern as areas on a surface of the card. Its specifications have been defined by the Solid State Floppy Disk Card (SSFDC) Forum, which began in 1996. It contains flash memory, particularly of the NAND type. The SmartMedia™ card is intended for use with portable electronic devices, particularly cameras and audio devices, for storing large amounts of data. A memory controller is included either in the host device or in an adapter card in another format such as one according to the PC Card standard. Physical and electrical specifications for the SmartMedia™ card have been issued by the SSFDC Forum, a current version of this standard being 1.0, which standard is incorporated herein by this reference.
Another non-volatile memory card is the MultiMediaCard (MMC™). The physical and electrical specifications for the MMC™ are given in “The MultiMediaCard System Specification” that is updated and published from time-to-time by the MultiMediaCard Association (MMCA). Version 3.1 of that Specification, dated June 2001, is expressly incorporated herein by this reference. MMC™ products having varying storage capacity up to 128 megabytes in a single card are currently available from SanDisk Corporation. The MMC™ card is rectangularly shaped with a size similar to that of a postage stamp. The card's dimensions are 32.0 mm. by 24.0 mm. and 1.4 mm. thick, with a row of electrical contacts on a surface of the card along a narrow edge that also contains a cut-off corner. These products are described in a “MultiMediaCard Product Manual,” Revision 2, dated April 2000, published by SanDisk Corporation, which Manual is expressly incorporated herein by this reference. Certain aspects of the electrical operation of the MMC™ products are also described in U.S. Pat. No. 6,279,114 and in patent application Ser. No. 09/186,064, filed Nov. 4, 1998, both by applicants Thomas N. Toombs and Micky Holtzman, and assigned to SanDisk Corporation. The physical card structure and a method of manufacturing it are described in U.S. Pat. No. 6,040,622, assigned to SanDisk Corporation. Both of these patents and patent application are expressly incorporated herein by this reference.
A modified version of the MMC™ card is the later Secure Digital (SD) card. The SD Card has the same rectangular size as the MMC™ card but with an increased thickness (2.1 mm.) in order to accommodate an additional memory chip when that is desired. A primary difference between these two cards is the inclusion in the SD card of security features for its use to store proprietary data such as that of music. Another difference between them is that the SD Card includes additional data contacts in order to enable faster data transfer between the card and a host. The other contacts of the SD Card are the same as those of the MMC™ card in order that sockets designed to accept the SD Card can also be made to accept the MMC™ card. This is described in patent application Ser. No. 09/641,023, filed by Cedar et al. on Aug. 17, 2000, which application is incorporated herein by this reference. The electrical interface with the SD card is further made to be, for the most part, backward compatible with the MMC™ card, in order that few changes to the operation of the host need be made in order to accommodate both types of cards. Specifications for the SD card are available to member companies from the SD Association (SDA).
Another type of memory card is the Subscriber Identity Module (SIM), the specifications of which are published by the European Telecommunications Standards Institute (ETSI). A portion of these specifications appear as GSM 11.11, a recent version being technical specification ETSI TS 100 977 V8.3.0 (2000-08), entitled “Digital Cellular Telecommunications System (Phase 2+); Specification of the Subscriber Identity Module-Mobile Equipment (SIM-ME) Interface,” (GSM 11.11 Version 8.3.0 Release 1999). This specification is hereby incorporated herein by this reference. Two types of SIM cards are specified: ID-1 SIM and Plug-in SIM.
The ID-1 SIM card has a format and layout according to the ISO/IEC 7810 and 7816 standards of the International Organization for Standardization (ISO) and the International Electrotechnical Commission (EC). The ISO/IEC 7810 standard is entitled “Identification cards—Physical characteristics,” second edition, August 1995. The ISO/IEC 7816 standard has the general title of “Identification cards—Integrated Circuit(s) Cards with Contacts,” and consists of parts 1-10 that carry individual dates from 1994 through 2000. These standards, copies of which are available from the ISO/IEC in Geneva, Switzerland, are expressly incorporated herein by this reference. The ID-1 SIM card is generally the size of a credit card, having dimensions of 85.60 mm. by 53.98 mm., with rounder corners, and a thickness of 0.76 mm. Such a card may have only memory or may also include a microprocessor, the latter often being referred to as a “Smart Card.” One application of a Smart Card is as a debit card where an initial credit balance is decreased every time it is used to purchase a product or a service.
The Plug-in SIM is a very small card, smaller than the MMC™ and SD cards. The GSM 11.11 specification referenced above calls for this card to be a rectangle 25 mm. by 15 mm., with one corner cut off for orientation, and with the same thickness as the ID-1 SIM card. A primary use of the Plug-in SIM card is in mobile telephones and other devices for security against the theft and/or unauthorized use of the devices, in which case the card stores a security code personal to the device's owner or user. In both types of SIM cards, eight electrical contacts (but with as few as five being used) are specified in the ISO/IEC 7816 standard to be arranged on a surface of the card for contact by a host receptacle.
Sony Corporation developed a non-volatile memory card, sold as the Memory Stick™, that has yet another set of specifications. Its shape is that of an elongated rectangle having electrical contacts on a surface adjacent one of its short sides. The electrical interface through these contacts with a host to which it is connected is unique.
As is apparent from the foregoing summary of the primary electronic card standards, there are many differences in their physical characteristics including size and shape, in the number, arrangement and structure of electrical contacts and in the electrical interface with a host system through those contacts when the card is inserted into the host card slot. Electronic devices that use electronic cards are usually made to work with only one type of card. Adaptors, both active and passive types, have been provided or proposed to allow some degree of interchangeability of electronic cards among such host devices. U.S. Pat. No. 6,266,724 of Harari et al. describes use of combinations of mother and daughter memory cards, which patent is incorporated herein in its entirety by this reference.
According to a primary aspect of the present invention, a very small (less than the size of a postage stamp) sub-card or daughter card containing non-volatile memory is removably connectable with one or more electronic cards or mother cards made according to different specifications, such as those of two or more of the above-described incompatible standards, while memory control and unique host interface functions remain on the mother cards. The mother cards individually interface, both mechanically and electrically, with host devices in the same manner as previously. But the non-volatile memory of each type of mother card has been removed and a standard memory interface substituted on the mother card. A universal memory daughter card is removably connectable with any of several different types of mother cards through the standard memory card interface. An advantage of the universal memory card is its reduced size and cost since the memory controller and host interface electronics reside on the mother cards. Since primarily only the memory storage cells are included on the memory card, its cost can be significantly lower than the memory cards described above that each also contain the memory controller and host interface. This standard memory interface between mother card and daughter card is to be distinguished from the host interface between the mother card and the host. While various adaptors may now be used to allow otherwise incompatible memory cards to communicate with a variety hosts, the subject of this aspect of the present invention is the mother/daughter card interface using a standardized universal interface.
According to another aspect of the present invention, such daughter memory cards may be removably carried by a larger substrate (such as one the size of a credit card) for distributing, handling and/or storing, and accessing the very small memory daughter cards. Because of their relatively low cost, the memory cards can be used for permanent storage of data. Video data, such as photographs, and audio data, such as music, are examples of the use of such memory cards by individuals. A storage card preferably carries one or more such memory cards and includes a surface area for the user to write by hand or otherwise uniquely identify or maintain a record of the data content of the memory card(s) attached to it. The memory cards may be distributed and sold through retail channels by selling the storage cards with one or more memory cards attached to each. The storage card may optionally include electrical contacts to which contacts of the attached memory card are connected through the storage card for the purpose of reading the data stored on the memory card, such as by inserting the storage card into a reader connected with a personal computer in the home or office, without having to remove the memory card from the storage card. Alternatively, the storage card may be sized according to the standards for a popular one of the cards described above, such as the Smart Card (ID-1 SE), with the memory card having a pattern of contacts and position on the storage card according to that same standard, thereby allowing the storage card with an attached memory card to be inserted into existing or suitably adapted card readers and read through the memory card contacts. Further contacts need not be provided on the storage card in order to access the memory card.
Additionally, the storage card for daughter memory cards may be provided with an intelligent controller capable of communicating with existing memory card readers using a variety of existing formats as outlined above for the mother cards. This controller may even communicate using the popular USB protocol in which case the storage card becomes functionally equivalent to the combination of a mother card and a reader and may plug into a passive adaptor meeting the mechanical standards for a USB connector.
In yet another variation, the identity of the daughter card(s) contained on the storage card may be read out using a contactless RF Identification mode. Suitable RF circuitry may be included either on the daughter card itself or on the storage card. In either case the power required to read out data contained in a predefined portion of the daughter card is provided by the incoming RF signal. The card then responds by modulating the incoming RF signal in such a way that the external RF receiver can interpret the code and thus uniquely identify the daughter card.
According to a further embodiment of the present invention, the daughter memory card is made in accordance with one of the existing card standards but with additional contacts added for connecting with the standard memory interface of the mother cards. This then allows the memory card to have a dual function: it can be used in the same manner as an existing card, directly with the host, or as a daughter card with one of the mother cards. As an illustration, contacts are added to the small Plug-in SIM card described above on the card's surface to surround the existing eight contacts that are provided as part of the ISO/IEC 7816 standard. The card may then be used in a host device in the same manner as the Plug-in SIM card, or as a memory daughter card when coupled with a mother card according to another one of the standards. For example, the contacts required for communication using ISO/IEC 7816 protocol may be used during powerup initialization to identify the card and allow authentication for access by the host or mother card to the data content of the card. This communication may then use the additional memory interface contacts at much higher speeds using the standardized communication protocol.
A patent application of Wallace et al., entitled “Use of Small Electronic Circuit Cards with Different Interfaces in an Electronic System” describes a combination of memories according to two different standards in a single memory card that shares a single set of card contacts. This application Ser. No. 09/633,089, filed Aug. 4, 2000, is hereby incorporated herein by this reference.
According to yet another aspect of the present invention, provision is made for accommodating future changes to the daughter card memory when such changes may affect the manner in which the mother card controller or a host controller needs to operate. A dedicated portion of the daughter card memory space accessible to the mother card controller (but preferably not to the user) contains data of specific operating parameters of the memory. Once the daughter card is detected, the mother card controller reads these parameters upon initialization, or whenever a new daughter memory card is inserted into the mother card receptacle, and then configures itself to operate the card and its memory accordingly. The memory system operating parameters that may be set in this way include algorithms for writing data into the memory, reading data from the memory, erasing blocks of the memory, correcting errors in read data, and the creation of a file system. Other parameters include levels of voltages required by the daughter memory card, the size of memory cell blocks that are the minimum number of cells erased together, the size of pages of memory cells within the blocks that are programmed together and other aspects of large memory cell block management. The parameters chosen to be stored for controlling operation of the memory are those expected to change in the future as the memory technology evolves. Other parameters may include information about the security features for content protection, the unique daughter card identification number, information on how the mother card should handle multi-bit per cell storage on the daughter card, as well as whether the daughter card is operable as a “cone time write”, multiple write, read only, or non-memory functions such as applications for optimized operation of the daughter card in specific hosts. The mother card controller, and in some cases the host system to which the mother and daughter cards are connected, then adapt to the parameters stored in a connected daughter memory card.
Additional features, aspects and advantages of the present invention are included in the following description of exemplary embodiments, which description should be taken in conjunction with the accompanying drawings.
The daughter memory card 11 is removeably received on each of the mother cards 13, 14 and 15 by some convenient electrical/mechanical arrangement thereon, shown to be in example positions 29, 30, and 31, respectively. Two rows of contacts 33 and 35 are shown on a surface of the memory card 11, as an example, for mating with a similarly arranged set of contacts within the mother cards 13, 14 and 15 when the memory card 11 is positioned thereon. Other contacting arrangements on the daughter card, such as a set of connecting surfaces on either or both flat surfaces, or contacts along one or more sides or edges, may be used. In the illustrated embodiment, each of the mother card 13, 14 and 15 substantially encloses the daughter card 11 but this is not required. A variety of methods to mate the cards may be used such as a slot, guide rail, or click-in-place mechanism. The daughter card may also include an indentation in a variety of shapes allowing removal with a narrow object such as a pencil point or nail, and it may also include a retention detent to ensure reliable contact. Alternatively, one or all of the mother cards 13, 14 and 15 may have provisions for retaining the memory card on its outside surface, such as by having a recessed surface region in the same shape as the memory card. In either of these examples, electrical contact is made with the memory card contacts 33 and 35 by appropriate electrical connectors within either the slot, recess or other physical memory card receptacle of each mother card. Many identical memory cards 11 will generally be used, one at a time, with any given mother card. Blank memory cards can be used in this way to store data from a host into which the mother card is inserted, or memory cards with data stored on them may be attached to a mother card for reading its data by a host into which the mother card is operably connected.
The mother card 13, in this example, has all the physical attributes and electrical host interface of a CompactFlash™ card, as well as a memory controller, but does not contain the mass non-volatile memory storage that is currently included in such a card. Rather, that mass memory is included in the daughter memory card 11 that is connectable with the mother card 13. Further, in this example, the mother card 14 corresponds to a MMC™/SD card with its mass memory removed and the receptacle 30 provided to receive the memory card 11 instead. Similarly, in this example, the mother card 15 corresponds to a Memory Stick™ card but with its mass memory removed and the receptacle 31 provided to receive the memory card 11 instead. Alternatively, other types of memory cards having the physical and electrical interface characteristics according to card standards other than CompactFlash™, MMC™/SD, and Memory Stick™, including those described above in the Background and others, may similarly be modified to remove their mass memory into the separate memory card 11.
The memory card 11 may have a capacity of 8, 16, 32, 64, 128 or more megabytes of non-volatile memory, for example of the flash EEPROM type, or of a one-time programmable memory that can be used for archival storage purposes. Indeed, memory cards of various capacities are expected to be sold to end users, so that only the amount of memory desired for a particular application need be purchased. The memory card is preferably plastic encased with electrical contacts of some convenient pattern across one or both surfaces of the card. The memory card 11 is preferably rectangular in shape with dimensions less than those of the present MMC™ or SD cards, an example being a card having substantially the same dimensions as the existing Plug-in SIM card.
The mother/daughter card combinations may be used with a variety of hosts. A host typically accepts one or perhaps two types of memory cards. Use of the memory card 11 separate from the mother cards that interface directly with various hosts therefore adds the convenience of being able to easily transfer data between two hosts that accept incompatible cards. For example, the card 11 can work with two cameras that are designed to save data of photographs into respective CompactFlash™ and Memory Stick™ cards that are accepted by the hosts' card slots. The daughter memory card 11 can then be moved between the two cameras. If the data format of individual photograph files saved by each camera is the same, for which an existing standard is predominate, a file stored on the memory card 11 by one camera may be read and processed by the other camera. The same easy transfer is also made possible when only one of two hosts is a camera and the other a utilization device, such as a personal computer, that processes or simply views photographs, but where the two do not have the same format card slot. In another example, the two hosts may be two types of audio devices with incompatible card slots. Other examples of uses of the daughter memory card 11 with multiple hosts that accept incompatible cards, as illustrated in
The separation of the memory card 11 from an existing card has uses beyond the transfer of data between incompatible mother cards. Even when only one host device is being used, or when two or more host devices have card slots according to a single standard, use of the separate memory card reduces the cost of storage for the user. A single mother card containing the host interface circuits and memory controller allows storage in a large number of less expensive memory cards 11. These memory cards may even be considered expendable and may be discarded after one or more uses, much like a consumable razor blade where the controller and host interface unit function analogous to a razor. The controller and host interface unit needs to be purchased only once for a given host device, in the form of a mother card, rather than having to purchase the unit as part of every memory card, as is currently the case with the memory cards discussed in the Background above.
The electronic functions of the host and cards are generally illustrated in
The mother card 49 also includes circuits 61 connected to the connector 51 to interface data and commands with the host. A programmable memory controller 63 is also included, often with a general-purpose microprocessor/microcontroller 65, to manage the memory within the card 55. The memory is provided within the card 55 by one or more integrated circuit memory chips 67. In order to minimize the cost of the daughter memory card 55, each such chip includes as few circuits as possible in addition to an array of memory storage cells. The physical and electrical interface at connector 57 is the same for all the different types of mother cards, so the programmable controller 63 is much the same. The physical and electrical interface at the mother card connector 51, on the other hand, is likely different for each type of mother card, as are the host interface circuits 61. The mother card interface follows a standard such as one of the existing standards described above in the Background. A number of such mother cards that satisfy different ones of the standards are contemplated.
As much of the memory control, addressing, programming, and reading circuits as practical are included within the mother card 49, rather than in the daughter memory card 55, in order to minimize the size and cost of the daughter memory card. Preferably, any circuits that work with the mother card microprocessor/microcontroller 65 to carry out memory controlling functions are included within the mother card 49. If a commercially available flash EEPROM integrated circuit chip 67 is used, some controlling functions are likely included in the memory chip such as state machine controlled programming, reading and erasing sequences. But the initiation and general control of such sequences are typically handled by the microprocessor/microcontroller 65 that executes firmware stored in a small code store (that can be ROM, SRAM, flash memory, or other code storing memory not shown) on the mother card. The daughter card may also contain all or part of this firmware (typically in a write protected area) and the microprocessor/microcontroller 65 may execute directly from this address space, or the firmware may be transferred from the daughter card 55 to a region of the code store on the mother card 49. Further, the microprocessor/microcontroller 65 preferably performs conversions of logical addresses received from the host into physical addresses within the memory chip 67, reassigns memory blocks such as may become necessary to avoid defective or overused blocks, performs background operations such as re-programming to restore margins between memory states (scrubbing) and compaction of data pages stored in large blocks (garbage collection), and similar types of functions where some level of intelligence is required.
A suitable memory chip 67 is commercially available from SanDisk Corporation or other companies. An example is a 512 mega-bit flash memory chip such as described in the “512 Mbit NAND Flash Product Manual,” revision 1.5, August 2001, available from SanDisk Corporation, which Manual is hereby incorporated herein by this reference. More than one such chip may be included in the daughter card 55. This memory chip is of a type allowing a large number of re-programming cycles in order to serve as computer mass storage in place of a conventional magnetic disk drive system. However, a less expensive flash EEPROM integrated circuit chip or other programmable memory chip such as mask ROM, one time programmable ROM, Ferroelectric RAM, Ovonic RAM, Polymeric RAM, Magnetoelectronic RAM, fuse RAM, or other forms of memory may be used instead if intended for an application requiring programming only once or just a few times. Such applications include the personal storage for archival or playback only of audio data, such as music, and video data, such as still photographs. If the daughter memory cards are made to be inexpensive enough, consumers can record such data once and then store the card away. The cost of a memory chip can be reduced when a large number of program/erase cycles are unnecessary. Such alternative memory chips can utilize either standard floating gates, dielectric layers, or programmable fuses as storage elements of its memory cells. It should be clear to the reader that the broad usage of different memory technologies and architectures in the daughter card inevitably will require different program/erase/read/file management/security algorithms and different voltage/power conditions for each of these different cards. Consequently the mother card must be able to supply such algorithms and operating conditions for the various daughter cards, and thus each daughter card must contain its specific and unique operating conditions and communicate these to the mother card upon request. This will advantageously be performed during initialization (boot-up) of the daughter card after it is inserted into and detected by the mother card.
It is also desirable to provide for the ability to use different forms of the memory chip 67 that may require the mother programmable controller card 49 to operate differently to control operation of the memory. Among the memory chip differences that may exist are binary (two-state) vs. multi-state (more than two state) cell operation, the memory cell erase block size, the amount of data that is programmed at one time, operating voltage(s) and algorithms for programming data, reading data, erasing blocks and performing error correction. If data stored on the daughter card are to be protected from copying, then specific algorithms for encryption or data protection may also be included together with their requirements for reserved blocks of memory. Data of such operating parameters may be stored in a portion of the memory chip(s) 67 that is not accessible to a host system but which is accessible by the memory controller 63. The memory controller of the mother card 49 then reads this operating parameter data from the memory chip(s) 67 upon initialization of the memory system and/or when a new memory card 55 is connected with the mother card 49. The read data then causes the memory controller to adapt to the operating parameters of the memory chip(s). This feature is also useful for allowing use of future improved or changed memory chips that may have such parameters changed.
During initialization it is a requirement that the memory controller 63 be able to communicate with the memory IC chip 67 at least to determine its operating parameters (voltage and communication protocol). Thus a standardized method of initial communication is defined, such as requiring all memory chips to communicate using at least one fixed voltage supplied by the power chip 53 and with a common signal format. For example, if all memory chips are required to communicate at 1.8 volts and subsequently identify that they need for example 3.0 volts (or 0.9 volt) for full operation, the mother controller card can then instruct its power unit to supply such voltage to facilitate further communication. Alternately, one or more dedicated pins may be included on the memory sub-card which the controller can interrogate to determine the required communication voltage range. After establishing initial communication, the other parameters required to transfer data may be determined. The MMC™ specification referenced previously describes one approach toward meeting these requirements.
A simplified approach for initialization is described in the following procedure. Upon application of power, the microprocessor or microcontroller on the mother card initializes itself and begins to monitor the card detect function described in detail below. Once a daughter card is detected, the mother card communicates with it using standardized protocol, timing, and voltage levels described above (for example, 1 MHz clock rates and 1.8 volt operation). A reserved sector located in a predefined location of the daughter card is then read which contains various other parameters needed for full operation of the daughter card. Such information includes the data format of the stored data (sector size and how to find the next sector), perhaps a file allocation table, maximum clock rates, unique card identification data (including security features), and information on required externally supplied voltages and timings and algorithms for write or erase. After the reserved sector is read and processed by the mother card, data communication between the mother and daughter cards can occur.
As mentioned earlier, some applications require restricted access to the content stored on the daughter memory card. This may be accomplished in a variety of ways. One approach using the ISO/IEC 7816 protocol is described below in conjunction with various embodiments in which the daughter memory card includes contacts to communicate using at least this protocol. Alternately, the daughter memory card may be designed to prevent transmission of data stored in certain predefined memory regions unless the mother memory card (or memory controller embedded in a host system) completes an authentication procedure to identify itself as authorized to access such data. Such protected data may include, for example, keys needed to decrypt content data stored in an otherwise accessible region of the memory card, or the ability to overwrite a lock protection feature restricting the ability of the memory card to accept new data or overwrite existing data.
As an example, the storage card 71 is rectangular in shape, with a length between 5 and 12 cm. and a width between 3 and 9 cm. It is preferable that the card be made thin but thick enough so that it is reasonably rigid, such as between 0.6 and 3 mm. in thickness. Exposed contacts 75 may optionally be included on a surface of the storage card 71 and connected to contacts 33 and 35 of memory cards 11-1 to 11-5 attached to it by conductors and connectors (not shown) that are formed as part of the storage card but this necessarily results in the card having a thickness sufficient to accommodate the conductive lines and additional insulation layers, as well as the respective connecting pins to each of the contacts on the daughter cards 11-1 to 11-5. A decoding integrated circuit (not shown) may also be included on storage card 71 to reduce the number of conductors while uniquely selecting one of several daughter cards 11-1 through 11-5. This allows data to be accessed on the several memory cards 11 without having to detach them from the storage card 71. A card reader 77, having a receptacle 79 for receiving the storage card 71, also includes the functions of the mother card 49 of
Alternately the storage card 71 may have embedded into it a controller chip that may provide the functionality of the mother card controller 49 of
In the case where an embedded controller chip supports a suitable protocol for connecting to the utilization device 83, the storage card is acting as both a memory card controller and a reader. Although any one of a variety of communication protocols may be chosen, the USB protocol or IEEE 1394 (“Firewire”) are particularly attractive for communication to a personal computer (PC). Other protocols such as ISO/IEC 7816, contactless, radio frequency wireless (such as BlueTooth or 802.11) may also be embedded in the storage card 71. In this case, the card reader 77 may be simply a mechanical adaptor and contain minimal or no active circuitry.
A more detailed example of a daughter memory card is shown in
Referring to the cross-sectional view of
Another example daughter card receptacle is shown in
The uniqueness of this leadframe design is that bonding pads on one or more sides of the memory die can be routed through the leadframe pattern to one or more different sides of the package, similar to a printed circuit board pattern. However, for this application the advantages of a leadframe over a printed circuit board include lower cost and reduced card thickness. The only wiring restriction is the inability to cross traces using only one level of leadframe interconnection, although this restriction is identical to that in common use today in matching any integrated circuit die into a suitable package; in practice die pad locations and package pin locations are considered together during the design phase of an integrated circuit. In prior art technology die are attached to a solid paddle region on the leadframe which prevents this wiring flexibility, but this embodiment allows more freedom in routing die interconnections from existing die to different package locations; specifically pads on two sides of a memory die may be routed to one edge of the daughter card. This routing flexibility occurs because the area under the memory die can be used for routing interconnections. The die is attached directly to and supported by (but electrically insulated from) the routing interconnections rather than a paddle area as is usually used. The leadframe 190 may then be formed using standard techniques to bring the daughter card interconnection pad locations 193 to a different vertical level than the bottom die surface (as shown in
Another example card structure is shown in
In a practical implementation of a removable card there are certain mechanical details that become important such as ease of proper card insertion, detection of a properly seated card, securely retaining the card while inserted, and ease of card removal. These are addressed in the designs shown in
Detection of a properly inserted card is typically accomplished by the mother card using a variety of techniques. One approach is for the physical presence of a card to move a mechanical switch, opening a dedicated circuit causing an interrupt of the microprocessor or microcontroller on the mother card. Another approach to card detection is for the daughter card to contain a short between two otherwise insulating pins on the mother card interface connector such that current flows upon insertion. The card detection process then causes the mother card to initiate an initiation process to determine how to communicate with the daughter card.
An alternative to the storage card 71 of
The memory card 153 can then be easily accessed while attached to the storage card 151. A card reader, such as that shown in
The analog circuit receives its operating energy through the antenna 161 from a nearby external radio frequency (r.f.) source, typically one that is from 10 cm to 10 meters away, depending on the frequency used. A small amount of non-volatile memory within the analog circuit, typically for 128 bits of data, stores a user's unique key, a unique manufacturer's card number, or some other code. This data is read when the circuit is powered up by the external r.f. source, and then transmitted back through the antenna 161. An external r.f. receiver, which can be integrated with the r.f. transmitter, then reads the transmitted code. The flash memory and security chips within the memory package are not activated during this operation since the required voltage supply is not connected with the external contacts of the memory card.
One application of providing the RFID tag within a memory card is for theft protection. In a retail store, for example, a cashier can activate operation of this memory after payment for the memory card has been received from the customer, by storing a unique code or otherwise. Any inactivated card will trip an alarm when passing through a store exit equipped with the r.f. transmitter and receiver.
The analog circuit can also be used to enable operation of the flash memory within the same card only when the code memory is activated. Thus, a memory card not activated by the sales clerk at the point of sale will not operate. Further, the RFID tag feature can also be used as a limited form of protected storage for a user key as an alternative to use of the security chip 89 (
Another application is for inventory control of the memory cards. A unique code stored by the manufacturer can be used for this. Cards being received into inventory are passed by the r.f. transmitter and receiver to read this code, which is then stored in an inventory control database. When a card is removed from inventory, the code is again read and so noted in the inventory database.
Alternately, the RFID function may be incorporated into the storage card 71 of
Although the present invention has been described through exemplary embodiments thereof, it will be understood that the invention is entitled to protection within the full scope of the appended claims.