Details

The DDR PHY uses start, stop, and step-size values for write DQ VREF training. If the stop value is not equal to the start value + a multiple of the step-size, then the final VREF setting can go beyond the maximum VREF range, causing the training to hang.

Workaround

Program the stop value as follows:

PI_WDQLVL_VREF_INITIAL_STOP = (multiple of PI_WDQLVL_VREF_INITIAL_STEPSIZE) + PI_WDQLVL_VREF_INITIAL_START