PS LPDDR4 settings?

We are trying to understand this option. My customer is using the exact same part number for LPDDR4 that is used on the Ultra96v2 board. For LPDDR4, the option for "address mirroring" is disabled. You can see the check box if you select DDR4 (not LPDDR4) as well as the dual rank check box in the PS DDR GUI. They copied everything exactly (or they thought they did), but we found some differences in the set, and we're trying to find out "why" and "how".

Ultra96v2 sets this option:

CONFIG.PSU__DDRC__ADDR_MIRROR {1}

But in our project this option is set as:

CONFIG.PSU__DDRC__ADDR_MIRROR {0}

When they forced this value to be "1" instead of "0" (overwriting the tcl), the LPDDR4 trained correctly without errors. How and where should they have made this change in the GUI? What exactly does it mean? It "appears" that the Ultra96v2 has address mirroring turned "on", but that's not even available in the GUI, and the default appears to be "0".

0 bhfletcher over 5 years ago

This was a recent change that we made directly in the BDF. I actually just blogged about this here -- FREE Xilinx Vitis 2019.2 Training for Ultra96-V2 (and update to the Ultra96-V2 BDF)

What GL Research found was that the Xilinx tools set the mirroring differently based on the version of Ubuntu that they were using. And Ubuntu 18.04 set it in such a way that it failed, which appears to be what you are finding. I'm not sure why the Ubuntu version causes that type of variability in the defaults from the Xilinx tools, but it can easily be corrected as you see in the latest Ultra96-V2 BDF.

Bryan
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