The SD Memory Card has a
mechanical write-protect switch so that vital data will not be lost accidently.
The SD Memory Card has a
mechanical write-protect switch so that vital data will not be lost accidently.
Rails on both sides of the card prevent it from being inserted inversely, and a notch prevents the card coming out of its socket if the appliance is dropped or bumped.
The metallic contacts are protected by ribs
that decrease the chances of damage by static electricity, or by contact damage
such as scratching.
For upward compatibility with the Multimedia Card, 1.4 mm rails enable sockets
to be provided that will accept an SD Memory Card or a Multimedia Card.
| Pin No. | Name | Description |
| 1 | CD/DAT3 | Card detect/Data I/O |
| 2 | CMD | Command |
| 3 | VSS1 | Ground |
| 4 | VDD | Power |
| 5 | CLK | Clock |
| 6 | VSS2 | Ground |
| 7 | DAT0 | Data I/O |
| 8 | DAT1 | Data I/O |
| 9 | DAT2 | Data I/O |
| Resister | Bit Width |
Definition Outline |
| OCR | 32 |
Operation Conditions Register Operation power supply voltage |
| CID | 128 |
Card Identification Register Manufacture ID, product name, serial No. |
| CSD | 128 |
Card-Specific Data Register Specification values of card |
| RCA | 16 |
Relative Card Address Register Card address between host and card |
| DSR | 16 |
Driver Stage Register Output drive capability |
| SDR | 64 | Sd
Card Configuration Register Special specification of SD Memory Card |
The SD Memory Card communicates with three signal lines - CLK, CMD and DAT.
CLK: CMD and DAT are synchronized to this CLK signal for input and
output.
CMD: The host issues a command to the card and the card returns the
response to the host.
DAT: DAT is a bi-directional I/O terminal.
An I/F driver, card I/F controller, flash memory
I/F, each register, and flash memory are inside the card. Reading the
information in the various registers enables the application to exercise optimum
control of the card and enables the performance of the application to be
improved. This allows the application products to be compatible with
cards of a broader range of generations and performance.