search

chipsalliance / fpga-interchange-schema

https://fpga-interchange-schema.readthedocs.io/
Apache License 2.0
51 stars 20 forks source link

interchange: Add sub-tiles, needed for Nexus FASM generation #57

Closed gatecat closed 3 years ago

gatecat commented 3 years ago

This is the easiest way to implement FASM generation for the Nexus, and other devices that have a similar problem of multiple tiles at the same grid location (ECP5, MachXO2, etc):

Screenshot from 2021-05-24 12-13-35

mithro commented 3 years ago

Do we already support tiles which cover multiple locations? Could we just times the grid by 2?

gatecat commented 3 years ago

Do we already support tiles which cover multiple locations?

No

Could we just times the grid by 2?

It'd have to be a lot bigger than two as there are a handful of places (4x or 5x I think), resulting in a tilegrid that was mainly gaps, which is likely to trigger pathological cases in algorithms that rightfully assume at least a vaguely contiguous grid

mithro commented 3 years ago

I'm not sure I like subtiles, but I can't think of a better solution so lets go ahead.