there are many situations where shorted outputs are appropriate (open
collector, unpopulated chips and more), I don't always make them passive
I just try to minimize the overhead and put an emphasis on open inputs
Dennis Saputelli
Brad Velander wrote:
>
> Dennis,
> I am curious, why do you make outputs passive? That would undo any
> checking for shorted outputs which I do see from time to time. Especially
> when designers are using new devices, particularly with large pin counts and
> complex functions.
> I use outputs for outputs, open collector, HIZ, etc. depending on
> the exact pin type, IO for bi-directional or multipurpose pins. This way I
> can use the ERC matrix to it's full capabilities for each job. When I get
> the common listing of IO pins possibly conflicting with other outputs, etc.,
> I take it to the firmware guys and have them sign-off on it to assure they
> have properly configured those IO pins to avoid any collisions. This also
> gives the firmware guys an opportunity to review that they have configured
> all their IO pins correctly during initialization, you would be amazed at
> the number of times I have found that they haven't.
>
> Sincerely,
>
> Brad Velander
> Lead PCB Design
> Norsat International Inc.
> #100 - 4401 Still Creek Dr.,
> Burnaby, B.C., Canada.
> V5C6G9.
> voice: (604) 292-9089 (direct line)
> fax: (604) 292-9010
> email: [EMAIL PROTECTED]
> www: www.norsat.com
>
> -----Original Message-----
> From: Dennis Saputelli [mailto:[EMAIL PROTECTED]]
> Sent: Tuesday, February 27, 2001 6:10 PM
> To: Multiple recipients of list proteledausers
> Subject: Re: [PROTEL EDA USERS]: newbie can't get power and groundplanes
> to connect up
>
> I think that in schem if the pin number is null (blank) then the pin
> name will be used in the netlist, no?
> If both are filled out then the pin number is used.
>
> I agree the ERC is useful, but as you point out there is a lot of
> potential hassles with the pin types (input, output, etc.), namely
> outputs shorted together that you do want shorted, likewise powers.
> Since I am most often looking for hanging inputs or open power pins to
> simply things (and consequently perhaps reducing the potential
> effectiveness of the ERC) I generally make power 'input', inputs
> 'input', outputs often passive.
> not perfect, but it has sped me up without problems (yet....)
>
--
___________________________________________________________________________
www.integratedcontrolsinc.com Integrated Controls, Inc.
tel: 415-647-0480 2851 21st Street
fax: 415-647-3003 San Francisco, CA 94110
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