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DDR3 calibration tool write leveling issue

Question asked by Leonardo Prates on Jan 29, 2015
Latest reply on Jan 30, 2015 by igorpadykov

I have a custom board similar to SabreSD using latest Linux release (Yocto dizzy). I use a standard notebook memory module (204 pin SODIMM 2GB 1333MHz/1600MHz) connected to IMX6Q processor. I have tested with a memory module manufactured by SMART Modules (2GB 1333MHz) and everything works well. I have used the calibration and stress tool (1.0.3) and I got calibration data necessary to complete memory configuration with success.



I have tested another module, manufactured by Avant that uses NANYA memory chip and this module works too, but write leveling calibration procedure with this module finishes so fast and result for the four related registers are 0x001F001F.



MMDC_MPWLDECTRL0 ch0 after write level cal: 0x001F001F

MMDC_MPWLDECTRL1 ch0 after write level cal: 0x001F001F

MMDC_MPWLDECTRL0 ch1 after write level cal: 0x001F001F

MMDC_MPWLDECTRL1 ch1 after write level cal: 0x001F001F



I have tried some times and always the result is the same. For DQS calibration  the results are as expected. For SMART M, the write leveling gives more realist result. I have made some tests and write leveling values that I get for SMART M works better in Avant memory than 0x001F001F result from write leveling calibration process for this module.



Someone knows the possible reason for this default value return?