Patent Publication Number: US-2009240884-A1

Title: Playback apparatus for multiple memory cards of the same type

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a playback apparatus for multiple memory cards of the same type, especially a playback apparatus for multiple memory cards of the same type that user selects multiple memory cards of the same type for playing. 
     2. Description of Prior Art 
     With the progress of the semiconductor technology, the capacity and security of memory cards, for example SD card, Mini SD card, MMC card and memory stick, increase a lot. User tends to buy multiple of memory cards of the same type for digital camera and cellular phone to store data. For example, user brings several SD cards to backup the photo taken by a digital camera during his trip. 
     In addition, multimedia devices for home or automobile equip with a card reader to read the MP3 or MP4 files stored in the memory card. However, these devices usually use only one memory card slot (or USB plug) to read the memory card and an adapter to select multimedia data from different sources, like cassette, CD, VCD and FM/AM, to play. Also these devices may equip with a multiple-in-1 (for example, 6-in-1) card reader for memory cards of different types (for example, SD/MMC/MS/MS Pro/SM/XD to PCMCIA.) 
     Unfortunately, customers tend to use multiple memory cards of the same type, like SD or MS cards, to prevent from compatible issue comes from different memory card type. Therefore, a playback apparatus for multiple memory cards of the same type can efficiently utilize the customers&#39; memory cards. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to provide a playback apparatus for user to select from multiple of memory cards of the same type for playing. 
     The present invention provides a playback apparatus for multiple memory cards of the same type. The apparatus reads at least one memory card and comprises of a plurality of memory card slots of the same type, a memory card selecting unit, a processor unit and a multimedia processor. The processor unit electronically connects to the memory card selecting unit, receiving a memory card detecting signal from the memory card selecting unit and sending a memory card selecting signal to the memory card selecting unit. The multimedia processor electronically connects to the processor unit and the memory card selecting unit, reading the data from one memory card through the memory card selecting unit under the control of the processor unit. Hence the playback apparatus for multiple memory cards of the same type selects one of the multiple memory cards of the same type, playing audio/video signals stored in the memory card. User therefore can select multiple memory cards of the same type for playing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram showing a playback apparatus for multiple memory cards of the same type according to a first embodiment of the invention. 
         FIG. 2A  is a block diagram showing a playback apparatus for multiple memory cards of the same type according to a first embodiment of the invention. 
         FIG. 2B  is a block diagram showing a playback apparatus for multiple memory cards of the same type according to a second embodiment of the invention. 
         FIG. 3A  is a diagram showing the host reading multiple of SD cards under SD bus mode. 
         FIG. 3B  is a diagram showing the host reading multiple of SD cards under SPI bus mode. 
         FIG. 4  is a circuit diagram corresponding to the block diagram in  FIG. 2A , showing the operation under SD bus mode. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a diagram showing a playback apparatus for multiple memory cards of the same type  10  according to a first embodiment of the invention. The playback apparatus for multiple memory cards of the same type  10  can be mounted in a case  20  with a front cap  22  pivotally connected thereon and a front cap switch  24  sensing if the front cap  22  is closed. The case  20  comprises of a plurality of memory card slots  26  of the same type for user to insert multiple of memory cards of the same type  30 . The memory cards  30  of the same type shown in the figure are SD cards and the number of memory card slots  26  is six. The embodiment of this invention has been presented for purposes of illustration and description. Different type or different number of the memory cards are within the scope of the present invention. 
     The playback apparatus  10  for multiple memory cards of the same type selectively reads the memory cards of the same type  30  then sends data to multimedia devices through cables, requiring power, sending or receiving control signals therefrom. As shown in  FIG. 1 , these cables includes digital output line  42 , IR tranceiving line  44 , panel I/O line  43 , analog video/audio output lines  40 , power switch line  45 , power line  46  and ground line  47 . 
       FIG. 2A  is a block diagram showing a playback apparatus for multiple memory cards of the same type according to a first embodiment of the invention. The playback apparatus  10  for multiple memory cards of the same type is adopted in a multimedia device with multiple memory cards. The playback apparatus  10  comprising a microprocessor  100 , a memory card control unit  110 , a memory card processor  120 , a video/audio processor  130  and a memory card selecting unit  160 . The memory card selecting unit  160  contains a plurality of memory card selecting switches  162  (not shown) to selectively read the memory card  30  in a memory card slot  26 . The memory card control unit  110  includes a memory card sensor  112  and a memory card selecting controller  114 , where the memory card sensor  112  detects if there is any memory cards  30  in each memory card slot and the memory card selecting controller  114  selects a memory card  30  in one of the memory card slots  26  to read according to the commands from the microprocessor  100  set by a user operating the control switches  140 . The memory card controller  120  reads the data stored in the memory card  30  selected by the memory card selecting controller  114  and sends it to the video/audio processor  130 . The video/audio processor  130  sends the data in memory card  30  to a speaker (not shown) or a display monitor (not shown) as audio or video output and it is not described here. 
     The microprocessor  100  processes the user commands sending from the control switches  140  to control the memory card selecting controller  114  for selecting the memory card  30  from one of the memory card slots  26 . In addition, the microprocessor  100  reads the information of memory card  30  sending from memory card sensor  112  (ex. number of memory cards, the location of the slots being occupied) and track number/time information transmitted from the memory card controller  120  in order to display them on a display  142 . 
       FIG. 3A and 3B  takes SD cards as an example, demonstrating that the host reads multiple SD cards by SD bus mode and SPI bus mode. As shown in  FIG. 3A , under the SD bus mode there must be a plurality groups of data port (DAT 0 ˜DAT 3 ) and command/response port (CMD) at the host in order to read multiple SD cards. At SPI bus mode, multiple SD cards are placed in parallel and a chip select signal (CS) decides which SD card is being used. In present invention, memory card processor  120  has multiple groups of chip select signal (CS) pin; therefore, it is applicable to either SD bus mode or SPI bus mode. 
       FIG. 4  is a circuit diagram corresponding to the block diagram in  FIG. 2A , showing the operation under SD bus mode. In this circuit diagram, the memory card control unit  110  and the microprocessor  100  have been integrated in a microprocessor unit  100 ′ while the memory card processor  120  and the video/audio processor  130  are integrated into a multimedia processor  122  in order to simplify circuit layout. The playback apparatus for multiple memory cards of the same type in  FIG. 4  also includes a front cap open/close sensor switch  170  electrically connecting to the microprocessor unit  100 ′, telling the microprocessor unit  100 ′ whether the front cap is open or closed. The multimedia device further contains a power supply  200  to provide power to the whole system. The microprocessor unit  100 ′ has a plurality of I/O ports, including memory card detect input port  101 , memory card select output port  102 , front cap detect input port  103 , power control port  104 , ACC detect port  105 , IR input port  106 , control signal input port  107 A, control signal output port  107 B, control command I/O port  108  and detect output port  109 . 
     When the power is on and the microprocessor unit  100 ′ detects ACC switch is closed, the microprocessor unit  100 ′ will check if the front cap is closed. The microprocessor will send a “front cap not closed” information through control signal output port  107 B if the front cap is not closed, while the microprocessor unit  100 ′ checks how many memory cards are there in the memory card slots  26  through the memory card detect input port  101  if the front cap is closed. If the memory card installed is the same as that of last power-on, the microprocessor unit  100 ′ controls the panel to display “continue playing”, meaning continue playing the content from last power-off. User can select a memory card by operating the buttons/panel or a remote control through the control signal input port  107 A or IR input port  106 , and the microprocessor unit  100 ′ will select the specific card through the memory card select output  102  according to the user command. The memory card selecting unit  160  selects a memory card for reading, and then the data on the selected memory card will be sent to the multimedia processor  122  through the memory card data bus. The multimedia processor  122  will process the data from the memory card and send it to audio output, video output or digital output. 
       FIG. 4  is another circuit diagram corresponding to the block diagram in  FIG. 2A , showing the operation under SPI bus mode. 
       FIG. 2B  is a block diagram showing a playback apparatus for multiple memory cards of the same type according to a second embodiment of the invention. The playback apparatus for multiple memory cards of the same type  10  is adopted in a automobile multimedia device with multiple memory cards, comprising units similar to those in  FIG. 2A  without a display  142 . The display  142  is omitted since the operating panel and display of the automobile stereo system can be used for the playback apparatus for multiple memory cards of the same type for input command and video displaying. 
     Although the present invention has been described with reference to the preferred embodiment thereof, it will be understood that the invention is not limited to the details thereof Various substitutions and modifications have suggested in the foregoing description, and other will occur to those of ordinary skill in the art. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the invention as defined in the appended claims.