Re: gEDA-user: Ideas for fixing slotting, methodology discussion, NOT implementation details!

[Dave N6NZ <n6nz@xxxxxxxx>]

Steven Michalske wrote:
> Slotting is broke,  the thread that prompted this this mail proves that.
> 
> no change we make here is going to work with how our users use slots
> 
> The answer to this is simple.
> 1. Deprecate slots, leave its functionality as is.
> 2. Implement the method that we come up with, without regard to slots.
> 3. Users get something that works in both cases.
> 	- Old way still work
> 	- New ways work "Better" or at least consistent
Good strategy.  In addition to not upsetting users, you will know when 
the new feature is "done right" when people move to it without being forced.

> So on to the new way.
> 
> This thread is NOT for dicusson of we need to fix the backend frontend  
> use SCHEME blah blah blah
> This thread is for what we need the new slotting to do well
> 
> What do we need to define?
> I will logically split a symbol and a component now, but we shouldn't  
> make the assumption that the will be split in the final implementation.
> 
> In a symbol:
> Specify what part of a slot(s) this symbol represents/requires.
> Specify what parts of a particular slot can be interchanged, e.g. pin  
> swapping
> Specify what power domains are required for the part.
> 	- e.g. level shifters and pins to power domains
> 	- e.g. in a 3.3V and 5V system, which voltage is this symbol on
> Specify what clock domain a symbol is in
> 	- e.g.  you can't move some parts across clock domains in VLSI
Seems to me this is just a couple of specific cases of the general case 
of design rule satisfaction.  Better to put in a generalized declarative 
mechanism to define requirements and prohibitions.

> 
> In a component
> Specify what slots this component provides.
> Specify a base part number
I suspect for anyone other than a hobbyist, this is an in-house 
manufacturing part number from the manufacturing database that maps onto 
the vendor part numbers of approved parts that purchasing runs off of.

> 	- this maps to many manufacture part numbers
And hopefully you fill up that map with a simple SQL query against the 
manufacturing data base.

> 		- manufacture part numbers map to pins/ports to pin numbers
> 
> Decided to drop the message into the wild.  input please folks
You mentioned pin swapping earlier -- pin swapping and slot swapping 
should be well handled by the new mechanism.  Which implies that clean 
and consistent back-annotation is a requirement.  Both of these are 
knotty problems, but I think the plain truth is that they both need to 
be solved at the same time.

Ideally, I'd like to be able to use the same symbol for a through-hole 
20 pin part or the 24 pin SMD part and back-annotate the correct pin 
numbers onto the schematic when the part is assigned. (I do that now 
with two symbols that have identical pin out so that cut/paste sort of 
gets me by, minus losing some attributes).  Also, I'd like to do slot 
and pin swapping during PCB layout and back-annotate the "as fabbed" pin 
numbers back onto the schematic.

Even more ideally, I'd like to be able to keep multiple attribute sets 
around for the same schematic and join a schematic with an attribute set 
to get the effective prints.  I was using that 20 years ago.  It's a 
very powerful capability.

-dave

> 
> Steve
> 
> 
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