ZQ cablibration error

[rayxie]

I used a P1011NEX in my design,and I found a ZQ calibration Error(DDR_ERR_DETECT[24]) when initializing DDR3,Which problems would trigger this error?

[Bulat]

DDR_ERR_DETECT[24] means Automatic Calibration Error (ACE), I am not sure why you called it "ZQ calibration Error".

ACE bit can be set if

1) Automatic CPO calibration was enabled by setting TIMING_CFG_2[CPO] to 11111 and an error was reported.

2) Incorrect termination of MDICx signals.

3) Write leveling calibration was not able to complete. This relates to improper settings of the DDR_WRLVL_CNTL register or board-level issues.