| | 345 | [=#sdio] |
| | 346 | === SDIO |
| | 347 | SDIO devices are covered by the SD protocol and are commonly used for WiFi modules. |
| | 348 | |
| | 349 | Device detection is done via two signals, CLK and CMD_RESP (open-drain). Once a device is detected by querying its operating modes data communication can occur using DATA[0-3] in 1-bit mode or 4-bit mode |
| | 350 | |
| | 351 | The following speeds are supported for SDIO devices: |
| | 352 | ||= Mode =||= Data Rate =||= Max Frequency =||= Max data rate at 4bit bus =||= Notes =|| |
| | 353 | || Default Speed (DS) || Single || 25MHz || 12.5MB/s || 3.3V / 1.8V || |
| | 354 | || High Speed (HS) || Single || 50MHz || 25MB/s || 3.3V / 1.8V || |
| | 355 | || SDR12/SDR25/SDR50 || Single || 100MHz || 50MB/s || 1.8V (up to 100MHz) || |
| | 356 | || SDR104 || Single || 208MHz || 104MB/s || 1.8V || |
| | 357 | || DDR50 || Dual || 50MHz || 50MB/s || 1.8V || |
| | 358 | * To support higher frequencies from 100MHz to 200MHz the driver and device-tree must support the ability to alter the pin control to increase drive-strength |
| | 359 | |
