NB2DSK01 - SD Card Reader

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 NB2DSK01 provides a reader for this type of memory card, by way of a DM1B-DSF-PEJ connector (HRS6090003-5), from Hirose.

Figure 1. Secure Digital (SD) memory card reader.

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 NB2DSK01's 3.3V power supply. Both switches are normally open (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.

Switch closure will result in a logical '1' being sent to the NanoTalk Controller. The NanoTalk Controller provides clock and command signals to the SD card, as well as reading/writing data.

From a user perspective, an SD card inserted into the motherboard's reader can be used to effectively 'boot' the daughter board FPGA device with a programming file stored on the card. Navigation of card contents and selection/download of a programming file is carried out through interaction with the TFT LCD panel. For more information, see Interacting with the Desktop NanoBoard NB2DSK01.

Location on Board

The SD card reader, labeled 'SD/Multimedia Card' and designated J8 is located on the solder side of the board, next to the DC volume control for the board's audio system.

Schematic Reference

The SD card reader circuitry can be found on Sheet 42 (CON_SD_HIROSE_609_0003_5.SchDoc, entitled SD-CARD HIROSE 609_0003_5) of the motherboard schematics.

Further Device Information

For more information on the DM1B-DSF-PEJ connector, refer to the datasheet (e60900048.pdf) available at www.hirose-connectors.com.