[PEDA] use prepared 'layout modules' on PCB

[Abd ul-Rahman Lomax]

At 03:37 AM 7/13/2006, news at a-38.de wrote:
>I would like to use some pre-layouted modules on my PCBs.

normal.

>I thought I can draw a blackbox in my SCH-lib with all required 
>signals connected to transfer points and then do the layout in my 
>PCB-lib, that ends up into the same transfer points. But as it 
>seems, the PCB-lib editor can't handle net-names and components 
>(resisitors, BGAs, etc.).
>
>It's hard for me to explain it in english. I hope you understand 
>what I mean!? Is there anyone who did this before? Or does anyone 
>know a workaround?

the behavior you are seeing is how Protel is designed to work. Nets 
are not assigned in symbol and footprint libraries (except for power 
nets with hidden power pins). So there is no workaround.

Instead, use the program the way it was designed.

Do *not* save this block as a library. Absolutely, that is not what 
you want. You have a collection of components there. If you save it 
in a library, it will become one component. (If that is what you 
want, i.e., a single component with an array of pads that are later 
used to load more than one component, you can do that, but usually 
this would be a bad idea, outside certain special applications.)

Instead take your block and save it as a PCB file. Do similar with 
the schematic of your block. Then, when you are creating a new 
schematic, you can place (copy and paste) the schematic block and 
wire it up. The schematic is what assigns nets. Then you load the net 
list into the PCB (or synchronize the PCB or update it, this process 
has been called by different names at different times).

(You can also assign nets with a net list. If you have your PCB block 
separated into its own file, and it has nets assigned, you could 
generate a net list from it. But this is not usually a good idea. It 
is *much* safer to create the net list from the schematic.)

(If it happens that you are designing boards without first creating a 
schematic, which people do from time to time, change your errant 
ways! This may seem to save some work, but it does not really save 
much under the best of conditions, and you will not be using the 
checking tools and a whole host of facilities that the schematic/pcb 
combination will give you. I create schematics even for very small boards.)