| 33 | |
| 34 | === eMMC bus |
| 35 | The initial bus speed is started with 25MHz SDR mode and depending on the capabilities of the host and device can negotiate to higher rates: |
| 36 | ||= Mode =||= Data Rate =||= IO voltage =||= Bus width =||= Frequency =||= Max data rate at 8bit bus =|| |
| 37 | || Legacy || Single || 3/1.8/1.2V || 1,4,8 || 0 - 26MHz || 26MB/s || |
| 38 | || High Speed SDR || Single || 3/1.8/1.2V || 1,4,8 || 0 - 52MHz || 52MB/s || |
| 39 | || High Speed DDR || Dual || 3/1.8/1.2V || 1,4,8 || 0 - 52MHz || 104MB/s || |
| 40 | || HS400 || Single || 1.8/1.2V || 4,8 || 0 - 200MHz || 200MB/s || |
| 41 | || HS400 || Dual || 1.8/1.2V || 4,8 || 0 - 200MHz || 400MB/s || |
| 326 | === MicroSD bus |
| 327 | The initial SD bus speed of 12.5MB/s is the default mode defined by SD1.0. Later a 25MB/s High Speed Mode (HS) was defined by SD1.1. As higher performance levels were needed to support new and faster devices the SD association introduced faster bus interfaces: UHS-I, UHS-II, UHS-III, and SD Express. The bus speed is started with 25MHz SDR mode and depending on the capabilities of the host and device can negotiate to higher rates: |
| 328 | ||= Mode =||= Data Rate =||= Max Frequency =||= Max data rate at 8bit bus =|| |
| 329 | || Default Speed (DS) || Single || 25MHz || 12.5MB/s || |
| 330 | || High Speed (HS) || Single || 50MHz || 25MB/s || |
| 331 | || UHS-I DDR50 || Dual || 50MHz || 50MB/s || |
| 332 | || UHS-I SDR50 || Single || 100MHz || 50MB/s || |
| 333 | || UHS-I SDR104 || Single || 208MHz || 104MB/s || |
| 334 | * Note that UHS-I requires support for voltage switching I/O rail from 3.3V to 1.8V |
| 335 | * All modes start at DS and negotiate up if supported on both host and card |