On Thu, 15 Mar 2001 12:41:43 +0100, Gisbert wrote:

>sorry, but I do not at all agree with you.

>>As for showing no connect pins - it is about as useful as adding a few
>>ficticious components to the schematic and marking them as not fitted and
>>nothing to do with the design?
>
>These pins are not fictitious and have everything to do with the design.
>May be it is not absolutely necessary to show them in all cases, but it is
>helpful for checks. For example I defined some weeks ago in a library a
>northbridge which exists in 2 versions: with and without an additional PCI
>bus connection. Some 60 pins of the 480 pin BGA are defined as NC in one
>version, as signal pins in the other. I find it explicitly useful to show
>them as unconnects in the version without second PCI bus.

Hmm, An old example - what about those 14 pin DIL reed relays some of which
have all 14 pins on the package and some of which have the 3 middle pins on
each side physically removed? Should I show pins which have been physically
chopped off by the manufacturer? Would it make any difference on other
parts if the NC pins were physically chopped off or not? 

>>This is quite telling, and actually exactly wrong - macros and hidden code
>>make it easy to figure out what is going on - that is the whole point of
>>using them and the founding principle of all Object Oriented Languages.

>I am just a hardware designer, so I would never dare judging the founding
>principle of Object Oriented Languages. But I spend hours with a logic
>analyzer searching for strange effects happening with microcontroller port
>pins, just because my software colleague swears he never touched that pin
>setting in his code, but it changes state when it should not. He was right,
>the code he had written himself was clean, but the macros written by
>someone else touched it. Macros and hidden code make it easy to figure out
>what is going on? I doubt it, as far as hardware-related software is
>concerned.

The guy who wrote the macro or the guy using it did a bad job. The macro
was doing more than it was supposed to, or it was insufficiently documented
or the guy using it didn't check what it was supposed to do. The sharp
knife/blunt knife argument - when someone cuts themselves with a sharp
knife the answer is not to only use blunt knives. 


Cheers, Terry.

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