What is dro ???

remove_cell

report_power_domain

gui_set_layout_layer_visibility -toggle [get_layers -filter {mask_name == metal5} -quiet]

1. Is everyone reuired to use upf ??? No, some use upf and some don't.

2. Is the vcc_m1 strap useless if there is no power switch ? ( Yes or No, it made the top level power mesh stronger, it will be hooked up at the top level. )

Several questions answered by Ki-Tae

1. Power ring around your block: to fix the floating power issue, for the narrow channel between macro and the edge. you may have power but it is not hooked to the top power network.

2. Side power switch which is used to supply the power to the macros. ( Some other people build power rings around the macro, I guess Da used several rows of power switch cells to compensate this <- Ki Tae doesn't quite like this idea since the stacks of vias may block quite some routing tracks )

3. Ki-Tae doesn't have floating piece of power which is quite clean. This should become my practice also.

4. Da had two pieces of metals shorted together, one labeled with vcc_m1, and the other vcc_gc. vcc_gc piece is not connected other vcc_gc, this is dirty which is not a problem for calibre, but it is a problem for icc_lvs.

5. Metal7 usage, this is from the top. Which may not be consistent.

So overall good practices:

1. add a ring to your block for potential stdcell power supply and avoid floating power nets.

2. reserve some space from macro to side boundary to have enough room to insert a column of power switch cells. Then you will have reasonably good power supply to the macro.

3. make sure no floating piece of power metals in your block, even if you connect them up with a thin metal.

4. use upf to set the correct voltage area, then place the power switch accordingly.

5. place the macros carefully to make sure there is room for power switch cell in between macros.