Re: gEDA-user: Hierarchy question

[Bill Cox <bill@viasic.com>]

Mike Jarabek wrote:

> Hi,
>
>    I ran into a similar issue with the Verilog netlister.  I skirted 
> the issue by adding a symbol with a special attribute attached, 
> 'device', where the value was `IPAD', `OPAD' or `IOPAD'.  When the 
> netlister enumerates the instances on the schematic, it builds lists 
> of the ports, based on the type attribute, and then ignores those 
> special symbols when the actual netlist instances are written out.  
> The VHDL netlister uses a similar scheme. (Literally.. ;-) You can 
> look in gnetlist/scheme/gnet-verilog.scm for info.
>
>    AFAIK, no `standard' symbol was created to convey this information. 
> Perhaps the time has come for this?
>
> Mike
I think we need to settle on some attributes for hierarchy connection...

I like your scheme, but it has some duplication in attribute info.  The 
direction (in, out, inout) info is encoded on the pintype attribute of 
the pin.  I'd rather have a single device attributes for all flags, like 
"FLAG" or "IO".  That makes it simpler to search for flags.

Either way, the current IO library has no consistent use of the device 
attribute.

Bill