If you are using multiple external memory interfaces in a single column, you might encounter the following error message when sharing RZQ pins:
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:
- Open all instances of the file
- Locate the instantiation of
- Comment out or delete the line that connects the port
s2ploadof this module to the signal
- 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.