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lnis-uofu / SOFA

SOFA (Skywater Opensource FPGAs) based on Skywater 130nm PDK and OpenFPGA
https://skywater-openfpga.readthedocs.io/en/latest/
MIT License
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Overlapping macro layouts #145

Closed mbaykenar closed 1 year ago

mbaykenar commented 1 year ago

Hi,

When I analyze gds outputs, I see that some macro block layouts are overlapping, such as grid_clb and sb_1_1:

image

Do you have a script/command to avoid of placement of any cell for those overlapping regions?

Regards,

Burak

ganeshgore commented 1 year ago

Hello Burak,

The lines you highlighted are just a bounding box of the cell (sb_1_1). As we used a rectilinear (+) shape, the boundary of the cell and the bounding box of the cell are different. All the standard cells are placed within the boundary of the cell, so the overlapping bounding box is not a problem.

mbaykenar commented 1 year ago

I didn't notice that. As you mentioned I checked gds of sb_0_1 and the shapes for switching blocks are not square.

image

I assume you chosed these rectiliniear shape to optimize floorplanning of tile-based architecture?

Regards,

ganeshgore commented 1 year ago

That's right, there are diagonal connections from CLB to SB modules. The rectilinear shape helps in that case.