Each calibration stage has its own set of sub-stages. CAL_SUB_STAGE provides the information of the sub stage being run during a calibration stage. This location is valid only when the current calibration stage status is in-progress.
| Calibration Stage | Sub-Stage | Description |
|---|---|---|
| DQS Gate Calibration | 0 | Initializing internal variables |
| 1 | Finding third edge stage. Rank-wise. | |
| 2 | Stable 0 confirmation before the third rise edge. Rank-wise. | |
| 3 | Find left edge of the noise of the third edge using fine taps of step size bigger than 1. Ranks wise. | |
| 4 | Find noise width of the third edge using fine taps of step size 1. Rank wise. | |
| 5 | Align to the center of noise using fine taps. Rank-wise. | |
| 6 | Add extra read latency of 1 to allow gate logic to capture full burst of the dqs. Rank-wise. | |
| 7 | Multi-rank read latency and coarse adjustments. | |
| 8 | DQS gate calibration exiting | |
| Write Leveling | 0 | Finding the 0x1 edge detection. Rank-wise sequential. |
| 1 | Stage 0 confirmation. Rank-wise sequential. | |
| 2 | Align to the center of noise using fine taps. Rank-wise sequential. | |
| Write Latency | 0 | Finding required latency and adjustment. Rank-wise. |
| 1 | Multi rank write latency and coarse adjustment | |
| 2 | Sanity Check. Rank-wise. | |
| Write DQ Per-bit Deskew and Centering | 0 | Initializing internal variables |
| 1 | DDR initialization sequence | |
| 2 | Finding best DQS delay offset | |
| 3 | Finding valid to noise region | |
| 4 | Finding left edge of noise | |
| 5 | Centering phase | |
| Read DQ Per-bit Deskew and Centering | 0 | Initializing internal variables |
| 1 | Move PDQS and NDQS to valid region of their associated data bits | |
| 2 | Move all the DQ lines to valid region sampling of their associated PDQS | |
| 3 | Move all the DQ lines to get start of the noise region sampling of their associated PDQS | |
| 4 | Move all the DQS lines together to get the noise region sampling of their associated NDQS | |
| 5 | Move PDQS and NDQS using fine taps of step size of 1 to get noise to valid region crossing | |
| 6 | Move PDQS and NDQS using fine taps of step size of more than 1 to get valid to noise region crossing | |
| 7 | Move PDQS and NDQS backward by one step size to go back to last valid sampling region | |
| 8 | Move PDQS and NDQS using fine taps of step size of 1 to get valid to noise region crossing | |
| 9 | Move PDQS and NDQS to center of the detected valid window | |
| 10 | Check sanity of the read data calibration | |
| 11 | Read calibration exiting |