The status of Read Per-Bit DQ Deskew can also be determined by decoding the CAL_ERROR result according to the table below. Execute the Tcl commands noted in the Manually Analyzing the XSDB Output section to generate the XSDB output containing the signal results.
| Error Code | Description | Recommended Debug Step |
|---|---|---|
| 12 | No valid data found for a given bit in the nibble by incrementing PQTR/NQTR IDELAY together using step size of 1 tap. | Check the dbg_rd_data, dbg_rd_data_cmp, and dbg_expected_data signals in the ILA. Check the pinout and look for any STUCK-AT-BITs, check vrp resistor, VREF resistor. Check BRAM_BISC_PQTR, BRAM_BISC_NQTR for starting offset between rising/falling clocks. |
| 13 | No valid data found for a given bit in the nibble by incrementing DQ IDELAY using step size of 1 tap. | Check the dbg_rd_data, dbg_rd_data_cmp, and dbg_expected_data signals in the ILA. Check the pinout and look for any STUCK-AT-BITs, check vrp resistor, VREF resistor. Check BRAM_BISC_PQTR, BRAM_BISC_NQTR for starting offset between rising/falling clocks. |
| 14 | Noise region not found for a given bit in the nibble by incrementing DQ IDELAY using step size of 10 taps. | Check for a mapping issue. This usually implies a delay is not moving when it should. Check the connections going to the XPHY and ensure the correct RIU is selected based on the byte being adjusted. |
| 15 | Noise region not found for a given bit in the nibble by incrementing DQ IDELAY using step size of 1 tap. | Check for a mapping issue. This usually implies a delay is not moving when it should. Check the connections going to the XPHY and ensure the correct RIU is selected based on the byte being adjusted. |