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Top Level Drawing with no interconnections. Why do you do that?

Tom Yunghans , 09-22-2020, 09:46 AM
Hi Robert,

It seems that you create a hierarchical structure to your schematics by creating a top-level drawing with a sheet symbol for each sheet, but you don't include any sheet entries or interconnections between the sheets at that level (see attached image from your Advanced PCB layout course) . I understand that this will make Altium recognize this as a "hierarchical" structure which affects the scope of net interconnection. Can you explain why you do this?


Tom Yunghans
robertferanec , 09-26-2020, 12:07 AM
I like to use ports, because they can automatically show on what page signal continues. And in the old Altium, if I wanted to use ports, I had to create a hierarchical project. That is the reason why you see this top sheet in our projects.

PS: I have not tried, but I think in the latest Altium, it may not be necessary (however then the projects will not be compatible with old altiums)
Tom Yunghans , 09-26-2020, 01:36 AM
So without the hierarchical blocks, the schematic will be treated as flat. In the newer versions of Altium, my understanding is that in a flat schematic, either ports or off-sheet connectors are used to interconnect pages (nets without one of these stay local to the sheet). I did a few simple tests and I believe I verified that. It sounds like you are saying that in the older versions of Altium, ports could only connect between sheets if the schematic were hierarchical (not flat). Therefore you added the empty sheets at the top level to make it appear hierarchical (even though it wasn't really hierarchical since there are no sheet entries in the blocks). However, this was sufficient to "trick" Altium into allowing you to use ports to interconnect the pages? Did I summarize correctly?
robertferanec , 09-28-2020, 07:03 AM
Yes, that is correct.
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