| # DRC errors in detailed routing - "Metal spacing violation" | |
| Tool: Detailed Routing | |
| Subcategory: DRC violation | |
| ## Conversation | |
| ### oharboe | |
| I think this is happening because two macros that need straight vertical wires between them don't have IO pins lined up and then the wires between the macros are criss-crossing. | |
| What is the difference and purpose of `MACRO_PLACE_HALO` vs `MACRO_PLACE_CHANNEL` and where do I use them, in the macro or where I'm using the macro from? | |
| Some thoughts on what I might do: | |
| - I could modify the halo macro to have a big enough "halo" (black area) where the wires can move horizontally to line up better with their destination pin in the other macro. | |
| - I could fix the io pin locations and floorplan so the router is able to use straight vertical wires instead of crisscrossing between two macros. This would reduce the need for a big halo. | |
|  | |
| ### vijayank88 | |
| @oharboe | |
| Variable description found here: https://openroad-flow-scripts.readthedocs.io/en/latest/user/FlowVariables.html#floorplan | |
| ### maliberty | |
| Note that mpl distinguished halo vs channel but mpl2 just uses halo. The distinction is that a channel is the space between two macros but the halo applies on all sides of the macro. | |
| I can't tell much from the picture. | |
| ### maliberty | |
| The setting are for x & y separately. Usually they are the same | |
| ### maliberty | |
| Imagine channel=10 and halo=5. Then macros must be 10 apart but standard cells must be 5 away from a macro. It is moot with mpl2. | |
| ### oharboe | |
| Updated docs in pull request based on the above: https://github.com/The-OpenROAD-Project/OpenROAD-flow-scripts/pull/1007 | |