NanoBoard 3000 - SD Card Reader (Host FPGA)

Frozen Content

The Secure Digital (SD) memory card is among a host of such cards available in today's world of storage-hungry devices, such as PDAs and digital cameras. The NanoBoard 3000 provides a reader for this type of memory card – for use by the NanoTalk Controller – by way of a KSDC012551 connector, from Konvee.

Secure Digital (SD) memory card
reader for use by the NanoTalk

The connector features a push-in/push-out ejection mechanism, locking the SD card firmly in place.

The connector provides Card Detection and Write Protection switches, to flag whether a card has been inserted, and the write status of that card. Both switches are commoned to the motherboard's GND and are normally open (i.e. when no card is inserted). When a card is inserted:

  • The Card Detection switch will close.
  • The Write Protection switch will close only if the SD card is enabled for writing to. If the card's write protect tab is in the 'Locked' position (typically down) the card is Read Only and the Write Protection switch will remain open.

Single inverter gate devices are used on the output lines from these switches (SN74LVC1G04, from Texas Instruments). While the switches are open, 4K7 pull-up resistors connected to the board's 3.3V power supply ensure logical '0' is sent to the NanoTalk Controller. Switch closure will result in a logical '1' being sent.

Location on Board

The SD card reader (designated J29) is located on the solder side of the board, above the SD card reader (J30) used by the User FPGA.

The two inverter gate devices (designated U65 and U66) are located to the right of the SD card reader (J29) used for the NanoTalk Controller.

Schematic Reference

The SD card reader circuitry can be found on Sheet 48 (CON_SD_KSDC012551.SchDoc, entitled SD-Card) of the motherboard schematics.

Further Device Information

For more information on the KSDC012551 connector, refer to the datasheet (KSDC012551.pdf) available at

For more information on the single inverter gate device, refer to the datasheet (sn74lvc1g04.pdf) available at

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