It is the time difference between the selected data edges and the immediately succeeding
selected clock edges.
| Active Clock Edge |
Active Data Edge |
Measures Setup Time Between ... |
| Falling* |
Falling | Falling data edges & falling clock edges |
| Rising | Rising data edges & falling clock edges |
| Both | All data edges & falling clock edges |
| Rising* |
Falling | Falling data edges & rising clock edges |
| Rising | Rising data edges & rising clock edges |
| Both | All data edges & rising clock edges |
| Both** |
Falling | Falling data edges & all clock edges |
| Rising | Rising data edges & all clock edges |
| Both | All data edges & all clock edges |
* Usable both for SDR (1 data edge/clock) & DDR (2 data edges/clock) systems.
** Meaningfull only for DDR systems.