Patent Publication Number: US-2004059860-A1

Title: Double-interface adaptor for memory cards

Description:
BACKGROUND OF THE INVENTION  
       [0001] In order to facilitate the portability and access of storage media, manufacturers developed many types of small and light memory cards and corresponding card drives. Currently, the mainstream memory card products in the market include: Multimedia Card (MMC), Smart Media Card (SM), Secure Digital Card (SD), Memory Stick Card (MS), and Compact Flash Card (CF). Because those memory cards have different specifications and sizes, corresponding card drive products or adapters have to be used, resulting in inconvenience and increased cost.  
       [0002] To solve above problem, some manufacturers developed a technology that utilize a single interface or drive to support different memory cards. Such an interface is a standard PCMCIA interface or a Compact Flash Card (CF) adapter, and usually is used in portable information appliances or consumer appliances; while card drives are usually used in PCs/system end. The existing card access approaches (interface or drive) are mainly because PCs don&#39;t support PCMCIA or CF interface and PCMCIA/CF interface doesn&#39;t support USB interface. In general, when the user wants to access the information stored in a memory card on a PC, a card drive is necessary, which impairs the portability of memory card products. On the other hand, PCMCIA/CF interface is not compatible with USB interface. Therefore it is necessary to integrate above two technologies.  
       [0003] Hence the inventor provides an innovative double-interface adapter for memory cards, which comprises of a double-interface adapter that can access the information stored in a memory card and a USB interface assembly that can be connected to the double-interface adapter. The double-interface adapter has a PCMCIA/CF and a USB interface, and it utilize an interface detection and selection circuit and a controller to automatically switch to the correct system interface selected (i.e., switch a PCMCIA interface to a USB interface, or vice versa).  
       [0004] In addition, the USB interface assembly in the double-interface adapter has no active electronic element, thus its size can be minimized. Compared to legacy card drives, it is more convenient.  
       [0005] Moreover, this invention utilizes a standard PCMCIA interface (or CF adapter) and embedded a USB interface and necessary control circuits in it. Thus it is not necessary to alter the original size and specification. Such a device is more competitive in price in the market.  
       [0006] This invention is further detailed in the following embodiments and illustrations.  
     
    
    
     BRIEF DISCRIPTION OF THE DRAWINGS  
     [0007]FIG. 1 is a structure diagram of this invention.  
     [0008]FIG. 2 is a block diagram of the circuit in this invention.  
     [0009]FIG. 3 is a block diagram of the circuit of a PCMCIA/CF adapter in this invention.  
     [0010]FIG. 4 is the flow diagram of this invention.  
                                                      Memory Card   10           Double-Interface Adapter   20           Controller   21           USB Bus Interface Circuit   211           PCMCIA/CF Bus Interface Circuit   212           Data Cache   213           Microprocessor   214           Memory Card Connector   22           Interface Detection and Selection Circuit   23           Power Transformation &amp; Protection Circuit   24           PCMCIA/CF Interface   25           USB Interface Assembly   30           PCMCIA/CF Connector   31           USB Interface   32                      
 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS  
     [0011] Please see the embodiment of this invention in FIG. 1, the double-interface device comprises of:  
     [0012] a double-interface adapter  20  that can access the information stored in a memory card  10  and a USB interface assembly  30  that can be connected to the double-interface adapter  20 . The double-interface adapter  20  delivers both a PCMCIA/CF interface and a USB interface (in FIG. 1, a PCMCIA/CF interface is shown). Please see FIG. 2 and FIG. 3, the double-interface adapter  20  comprises of:  
     [0013] a controller  21  with a standard USB Bus interface circuit  211  and a standard PCMCIA/CF Bus interface  212  embedded, a cache  213  for data transfer to cache data in the data transfer process between the memory card and the standard USB interface, a microprocessor  214  with a ROM, a cache, and an access control interface embedded to perform detection, switching, and control, a connector  22  to host a memory card  10 , through which the data are transferred to the memory card  10  under the control of the microprocessor  214 , and an interface detection and selection circuit  23  to deliver detection and switching functions, a power transformation and protection circuit  24  to convert the voltage applied on the USB Bus interface or PCMCIA/CF Bus interface into the internal voltage on the double-interface adapter  20  with over current and surge protection functions, a PCMCIA/CF interface  25  to support a PCMCIA/Compact Flash storage device.  
     [0014] The USB interface assembly  30  comprises:  
     [0015] a USB interface;  
     [0016] a PCMCIA/CF connector  31  to connect to the double-interface adapter  20  to switch to the said standard PCMCIA/CF interface (at the same time, the controller  21  in the double-interface adapter  20  supports and control the circuit for the standard USB interface to determine whether to select the USB interface to perform data transfer);  
     [0017] a convert circuit to connect the circuit for the USB interface to the predefined position on the PCMCIA/CF connector.  
     [0018] From above description we can see that the double-interface device supports both system interfaces. A program for processing above two system interfaces is hosted in the internal controller  21  of the double-interface adapter  20  to support instructions and communication protocols generated from different interfaces. As shown in FIG. 4, after the system is launched and the double-interface adapter  20  is powered, the double-interface adapter  20  will switch to the correct working mode and activate an appropriate system interface according to the system detected by the interface detection and selection circuit  23 . After the system interface is activated, the microprocessor  214  will accept the instructions from the system end and process them according to the specification for the system interface and generate appropriate response.  
     [0019] The above embodiment shall not constitute any limitation to the invention. It is stated that any implementation result from any equivalent replacement or modification to the invention should fall into the category of this invention.