Use the Mentor Graphics Pads tool for viewing the BGA breakout and routing examples provided by Lattice.
Download the free Mentor Graphics Pads tool from
here.
OR
Use the Cadence Allegro Viewer after converting the .asc file to .brd file.
Follow these steps to convert the .asc file to .brd file:
1. From the Cadence Allegro Viewer, click Import -> CAD translators -> PADS.
2. Select the .asc file that is available in the BGA breakout and routing folder as input.
3. Provide a name for saving the .brd file.
This file can be opened with Cadence Allegro Viewer.