Breakout Board for SD-MMC Cards

Replacement:BOB-11403. We've revised this board to fit a new SD card socket, it has stayed the same otherwise. This page is for reference only.

With SD and MMC memory prices dropping, the time is right for mass storage and datalogging. This breakout board will allow you to breakout the SD/MMC socket to a standard .1" 11-pin header. Perfect for breadboarding and the likes. Board comes fully assembled and tested as shown.

This is the new Push-Push type socket. The board has 11 pins:

  • COM : Common - Connects to the housing
  • WP : Write Protect Detect Switch
  • CD : Card Detect Switch
  • P9 : Not used in SPI Mode (Pin 9 on SD Card)
  • IRQ : Not used in SPI mode (Pin 8 on SD Card)
  • DO : Serial Data Out
  • GND : Ground - Connect this to COM to ground the housing
  • CLK : Serial Clock
  • VCC : 3.3V Power
  • DI : Serial Data In
  • CS : Chip Select

    It is recommended that you connect the COM pin to GND if you plan to use the CD or WP pins.

  • 1.3x1.5"


Looking for answers to technical questions?

We welcome your comments and suggestions below. However, if you are looking for solutions to technical questions please see our Technical Assistance page.

  • TheTrustedOne / about 15 years ago / 3

    If this is just the socket on a piece of board, no other electronics, dont you thinks that $22.45CAD is just a little expensive? considering the socket itself is $5.00 that mean $17.54 for less then 1 Sq In of circut board?

    • TheTrustedOne / about 15 years ago / 2

      $17.45 Sorry, It's early

    • Maxwellfire / about 12 years ago / 1

      now it's only $9.95!

    • Hopworks / about 14 years ago / 1

      Agreed. I think the price on this is way over inflated. I was going to add to my cart but had second thoughts. Now those thoughts are not only confirmed, but negative.

  • Member #330148 / about 12 years ago / 1

    When will the product be available?

  • linagee / about 12 years ago / 1

    "Simplified SD Specifications" is a bad link.

  • baum / about 12 years ago / 1

    mine is red.

  • CrazyCasta / about 12 years ago / 1

    Hmm, that didn't highlight specs have moved to: Simplified SD Specifications.

  • CrazyCasta / about 12 years ago / 1

    The Simplified SD Specification seems to have moved to:

  • Member #263043 / about 12 years ago / 1

    Is this compatible with PIC18F4550?

  • The new SD library included in Arduino 22 IDE works great with this card. No problems at all.

  • This has been asked before, but I have yet to find an answer.
    The SD-MMC package in the library has an SW pin, but it seems to be undocumented on when it would be connected.
    Does anyone know what the SW pin does?

  • Member #147549 / about 13 years ago / 1

    If that board was just a bit longer, and had some plated thru holes for some added circuitry, I could place a few essential parts close enough to avoid noise pickup...Otherwise on some development board systems, I cant get it to read any faster that about 1mhz, and won't write at all...even if throttled down to 12khz!
    Also, powerdown/powerup involves disconnecting/connecting all the logic pins for a proper reset..really need that breadboarding space to be there so it can be done right. At the very least, pullups have to be added in most cases.

  • scharkalvin / about 14 years ago / 1

    If you look carefully you will see that they are using the same socket as the SD sniffer board. The sniffer board does not bring out the CD and WP switches, nor the common connection, but they are there on the socket and you probably can solder wires at the right points to get at them. The SD sniffer would be $8 cheaper and just as useful, especially if you don't need the card detect and write protect signals.

  • mpechner / about 14 years ago / 1

    If I want to connect this break out to a 74hc4050E, will the schematic and the fat16 library for the micro sd shield work? I understand I'll connect to the same pins on the arduino.
    I want to put this on a proto area of another shield. Same the extra height.

  • forkyaf / about 14 years ago / 1

    Can someone tell me if this can be used in SD communiction mode and not SPI?

  • Dragon2 / about 14 years ago / 1

    Can anyone point me in the right direction to use this with an arduino thanks

    • baum / about 13 years ago / 1

      If you don't have a level shifter, 3 diodes will work.

    • SirionBV / about 13 years ago / 1

      Hi, Managed to get it working with an arduino.
      You should use an level converter to 3.3v , I used the 74HC4050N in between, very simpel circuit. After that you can use the new SDFat library for the arduino.
      Connections are CS to pin10, Mosi to pin11, CLK to pin13 and miso to pin12

  • Member #87485 / about 14 years ago / 1

    It's likely because they are using a more expensive socket, it has grounding, WP detection, and Card Detection switches, as well as having been broken out :P

  • bushing / about 14 years ago / 1

    The price on this really needs to be adjusted; the SD sniffer ( is $9.95 and does everything this does and more.

  • acqu1 / about 15 years ago / 1

    This seems very pricey.

  • Otedawg / about 15 years ago / 1

    Would someone post the Eagle files? I am trying to use this in a design. Thanks

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