Software can use the DLL presets to automatically switch the DLL output frequency. There are three DLL presets. They are programmed using the SDx_DLL_DIV_MAP0 register. Software programs the SD_DLL_REF_CLK output frequency to 1200 MHz.
| I/O Frequency | Preset | DIV_MAP register | Divide By | |
|---|---|---|---|---|
| Field | Value | |||
| 200 MHz | 0 |
[DIV_0] |
0Ch
|
6 |
| 1 | [DIV_1] |
18h
|
12 | |
| 2 | [DIV_2] |
30h
|
24 | |
| 100 MHz | 0 | [DIV_0] |
18h
|
12 |
| 1 | [DIV_1] |
30h
|
24 | |
| 50 MHz | 0 | [DIV_0] |
30h
|
24 |
| 30 MHz | 0 | [DIV_0] |
50h
|
40 |