xD-Picture Card is a flash memory card format, used mainly in digital cameras. NAND Flash, with additional ID commands.
xD cards are used in a select number Olympus and Fujifilm digital cameras and Olympus digital voice recorders but are now being phased out by both companies.
The memory format used by xD cards is not well-documented. It is difficult to study it directly, since most camera devices and most USB card readers do not provide direct access to the flash memory. Since the cards are controller-less, cameras and card readers must perform wear leveling and error detection themselves, and they normally hide the portion of the memory which stores this information (among other things) from higher-level access.
Because of its higher cost and limited usage in products other than digital cameras, xD has lost ground to SD, which is broadly used by PDAs, personal computers, cellular phones, digital audio players and most other digital camera manufacturers.
1 mm pin pitch.
3.3V power.
Standard NAND-Flash command set, plus additional
| 18-pin Flash Card Pin | Name | Direction | Description |
|---|---|---|---|
| 18 | GND |  | Ground (+Presence detect) |
| 17 | R/-B |  | Ready/-Busy (Open-drain) |
| 16 | -RE |  | Read Enable |
| 15 | -CE | | Card Enable |
| 14 | CLE | | Command Latch Enable |
| 13 | ALE | | Address Latch Enable |
| 12 | -WE | | Write Enable |
| 11 | -WP | | Write Protect |
| 10 | GND | | Ground |
| 9 | D0 |  | Data0 |
| 8 | D1 | | Data1 |
| 7 | D2 | | Data2 |
| 6 | D3 | | Data3 |
| 5 | D4 | | Data4 |
| 4 | D5 | | Data5 |
| 3 | D6 | | Data6 |
| 2 | D7 | | Data7 |
| 1 | Vcc | | Power |
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