Description:
The normal procedure to migrate a design to Lattice Diamond is by using the \u201CImport ispLEVER Project..\u201D option in the Lattice Design software. While importing, when you check \u201CCopy design source to Implementation's Source Directory\u201D, all RTL and schematic (*.SCH) files are copied to the Lattice Diamond generated source directory. However, any of the *.sym files, which are the custom symbol files generated by the user, do not get copied to the source directory.
Solution:
The symbol files and other RTL/Schematic files must be in the source directory.
To overcome this the user needs to manually copy all *.sym files to the Lattice Diamond generated source directory.
Note: If they are not using any custom-generated symbols this is not an issue.
An example of the error which is displayed in the diamond console is :
@E: Unable to load symbol My_CUSTOM_SYMBOL_1
@E: Unable to load symbol My_CUSTOM_SYMBOL_2
@E: Unable to load symbol My_CUSTOM_SYMBOL_3
@E: Unable to load symbols for <Drive>:/<My Project Directory>/My_Schematic.sch