At the top level of the chip, special padcells are use to connect signals to the external package. Additional commands are provided to specify the placement of padcells, bondpads and bumps
The definition of the padring is split into three separate parts:
- A library definition which contains additional required information about the IO cells being used
- A package description which details the location of IO cells around the periphery of the design
- A signal mapping file that associates signals in the design with the IO cells placed around the periphery
The separation of the package description from the signal mapping file allows the same IO padring to be reused for different designs, reducing the amount of rework needed.
For more details refer to doc/README.md