Read Centering (Complex) - 1.0 English

Versal ACAP Programmable Network on Chip and Integrated Memory Controller LogiCORE IP Product Guide (PG313)

Document ID
PG313
Release Date
2022-12-14
Version
1.0 English
The final stage of DQS read centering that is completed before normal operation repeats the steps performed during MPR DQS read centering but with a difficult/complex data pattern. The purpose of using a complex pattern is to stress the system for SI effects such as ISI and noise while calculating the read DQS center position. This ensures that the read center position can reliably capture data with margin in a true system.

This is accomplished as follows:

  1. Reset PQTR and NQTR delays to 0 and verify that data is being properly read.
  2. Delay the DQ/DBI until the noise region is found. Use short read bursts until noise region is found, then use long reads for accurate edge detection.
  3. Delay the clock strobe to return to the valid region, continue until the noise region on the other side is found. Use short read bursts until noise region is found, then use long reads for accurate edge detection.
  4. Center the strobe in the valid region.
Table 1. Read Centering (Complex) Registers
Register Name Quantity Description
Fx_RDCMPLX_IDELAY_OFFSET Nibble Idelay at left edge. (in noise region)
Fx_RDCMPLX_PQTR_LEFT_SHORT Nibble Tap value for left side of window with short complex pattern, rising edge (noise to valid)
Fx_RDCMPLX_NQTR_LEFT_SHORT Nibble Tap value for left side of window with short complex pattern, falling edge (noise to valid)
Fx_RDCMPLX_PQTR_LEFT Nibble Tap value for left side of window with long complex pattern, rising edge (noise to valid)
Fx_RDCMPLX_NQTR_LEFT Nibble Tap value for left side of window with long complex pattern, falling edge (noise to valid)
Fx_RDCMPLX_PQTR_RIGHT_SHORT_FCRSE Nibble Short pattern with 10-increment steps for right edge, rising edge (valid to noise)
Fx_RDCMPLX_NQTR_RIGHT_SHORT_FCRSE Nibble Short pattern with 10-increment steps for right edge, falling edge (valid to noise)
Fx_RDCMPLX_PQTR_RIGHT_SHORT Nibble Tap value for right side of window with short complex pattern, rising edge (valid to noise)
Fx_RDCMPLX_NQTR_RIGHT_SHORT Nibble Tap value for right side of window with short complex pattern, falling edge (valid to noise)
Fx_RDCMPLX_PQTR_RIGHT Nibble Tap value for right side of window with long complex pattern, rising edge (valid to noise)
Fx_RDCMPLX_NQTR_RIGHT Nibble Tap value for right side of window with long complex pattern, falling edge (valid to noise)
Fx_RDCMPLX_PQTR_FINAL Nibble Final centered tap value for PQTR
Fx_RDCMPLX_NQTR_FINAL Nibble Final centered tap value for NQTR