I want to know if this is correct, in my Core module I had multiple sub-modules, when I fill in the "FP_PDN_MACRO_HOOKS" I usually use the power pin connection" vccd1 vssd1 vccd1 vssd1". Usually that generates some LVS errors because some sub-modules are not connected to those pins, so I go to OpenROAD -GUI and just choose the power grid that passes over the module.
e.g. the "6__7_" module is connected to vccd1, and vssd1. but as u can see in the picture the power pin cannot be connected to the module "7__6_" so I used power pins vdda1 and vssa1.
My questions are: that is a correct connection? that could generate some error? How can I uses only vccd1 and vssd1?
04/21/2023, 10:56 PM
1. You could make your macros taller so that they will always connect to at least 1 vccd1, vssd1.
2. You could manually place your macros so that they will connect to vccd1, vssd1.
As vdda1 is usually 3.3V, you probably don’t want to use that.
04/21/2023, 11:48 PM
In these modules I can do it (change the size or place of the macro) but in other areas (like in the image) with more connections and sub-modules around I can't. is there another solution?
04/22/2023, 1:22 AM
There are 8 repeating power straps. Ideally, your macros should be tall enough to intersect with all of them so you don’t need to worry about placement. You can set the macro size when synthesizing.
vccd1 and vccd2 are both digital power supplies, nominally 1.8V, so you might be able to connect to either of those. Some designs short the digital power supplies: vccd1-vccd2 and vssd1-vssd2. I cannot comment on the merits or demerits of either of these suggestions.