Secure Digital
SD=Secure Digital 
MMC with added DRM like functions.
Physical size
| Width: | 24 mm |
|---|---|
| Length: | 32 mm |
| Thickness: | 2.1 mm |
| Card Volume: | 1596 mm3 |
| Weight: | ~2 g |
| Operating Voltage | 2.7 - 3.6V |
Version
| Version: | Name: |
|---|---|
| 1.0/1.1 | SD |
| 2.0 | SD-HC (HC=High capacity) |
History
- SD 1.0 (October 2001)
- Complete Standard NDA & $$$
- Simplified Standard released 2005
- Based on MMC Standard
- One device on bus
- 4bit 25MHz bus (12.5MB/ s)
- Alternative SPI bus interface
- 16MB- 2GB (4GB available)
- SD 2.0 (April 2006)
- SDHC (4GB- 32GB)
- Optional 8- bit bus
- 3 speed classes(2MB/ s, 4MB/ s, 6MB/ s)
Speeds
| 4x: | 600 KB/s |
|---|---|
| 16x: | 2.4 MB/s |
| 40x: | 6.0 MB/s |
| 66x: | 10 MB/s |
| 133x: | 20 MB/s |
Pinout
Pin Layout
/ ||||||||| | ||1 8 | |9 |
SD Mode
| Pin | Name | Dir | Description |
|---|---|---|---|
| 1 | CD/DAT3 | ↔ PP) | Card Detect/Data Line 3 |
| 2 | CMD | ↔ PP) | Command Line |
| 3 | VSS1 | ─ | Ground |
| 4 | Vdd | ← | Voltage Supply [2.7v or 3.6v] |
| 5 | Clock | ← | Clock |
| 6 | Vss2 | ─ | Ground |
| 7 | DAT0 | ↔ PP) | Data Line 0 |
| 8 | DAT1 | ↔ PP) | Data Line 1 |
| 9 | DAT2 | ↔ PP) | Data Line 2 |
Note: Direction is memory card relative to host
PP) Output is Push-pull.
SPI Mode
| Pin | Name | Dir | Description |
|---|---|---|---|
| 1 | /CS | ← | Chip Select/Slave Select (SS) |
| 2 | DI | ←PP) | Master Out/Slave In (MOSI) |
| 3 | VSS | ─ | Supply voltage ground |
| 4 | VDD | ← | Supply voltage |
| 5 | CLK | ← | Clock (SCK) |
| 6 | VSS | ─ | Supply voltage ground |
| 7 | DO | ↔PP) | Master In/Slave Out (MISO) |
| 8 | IRQ | not connected or IRQ | |
| 9 | NC | not connected |
Note: Direction is memory card relative to host
PP) Push-pull.
Related connectors
Additional information
Sources
- Presentation about FreeBSD's SD/MMC Implementation by Warner Losh