Error Can Occur When Using Multiple EMIFs in a Single Column and Sharing RZQ Pins

If you are using multiple external memory interfaces in a single column, you might encounter the following error message when sharing RZQ pins:

Error:

Internal Error: Sub-system: AMM,

Fkile: /quartus/db/amm/amm_atom_mod_util_impl.cpp, Line: 4623

Cannot merge atoms - incompatible sources.

The workaround for this problem is to modify an RTL file deployed by the EMIF IP. Proceed as follows:

1. Open all instances of the file altera_emif_arch_nf_oct.sv.
2. Locate the instantiation of twentynm_termination_logic.
3. Comment out or delete the line that connects the port s2pload of this module to the signal oct_s2pload.
4. Recompile your design.

You should use a separate RZQ resistor for each external memory interface going forward, because doing so will improve the accuracy of calibrated termination settings.

This problem will be fixed in a future version.