[SI-LIST] Re: [SI-LIST]: Wired-AND VS Wired-OR logic

Good Morning,

In my experience wired logic is named using positive logic conventions.
The function of the wired signal is true when in the more positive voltage 
state.

For "Wired AND" signals, all of the driving signals must be in the state that
allows the output of the function to rise to the true state.  This is most 
commonly
achieved using NPN open collector outputs to drive a summing resistor junction. 
 
When all of the transistors are "off" the output becomes true.  Any transistor 
sinking current from the junction yields a false state.

"Wired OR" systems use either NPN open emitter drive for unsaturated logic such
as ECL or PNP open collector for saturated logic drive.

Hope this helps.

Regards,
dav0
David Lieby


Sunil Kumar wrote:
> 
> Hello Anand,
> 
> ECL family can be used in wired-OR fashion.
> Outputs of different gates can be tied together
> to one common resistor to VEE. The value of
> this resistor depends on the number of outputs
> connected.
> 
> Regards,
> 
> Sunil
> 
> On Wed, 24 Apr 2002 Anand.Kuriakose@xxxxxxxxxx wrote:
> 
> >
> >
> >
> > Hi all,
> >
> > We can introduce wired-AND logic by connecting 2 or more open-drain (also
> > open-collector) outputs together with a single pull-up resister. The logic 
> > of
> > AND logic results as follows: If one or more of the drivers asserts the 
> > output
> > to low state (electrically low ), the equivalent output is low, which is 
> > how an
> > AND gate functions. Also the connected signals have to be active-low 
> > signals.
> >
> > I have seen many documents refering to the above scenario as wired-OR 
> > logic. It
> > doesnt make sense. Also the PCI spec 2.2, sec2.1 refers to O/D signals (ex 
> > INTX#
> > and SERR#) as to be capable of introducing wired-OR logic.
> >
> > So what is wired-OR logic? How do we realise this logic? Does the active 
> > level
> > of the connected signals make the difference?
> >
> > Also one more question.  When it comes to wired-AND logic, only one device 
> > can
> > assert its output low. We cannot have more than one device asserting its 
> > output
> > low simultaneously. Am i right in saying so. If yes, is this allowed in 
> > wired-OR
> > logic.
> >
> > Thanx in advance for all the valuable inputs.
> >
> > Regards,
> > Anand Kuriakose.
> >
> >
> > ------------------------------------------------------------------
> > To unsubscribe from si-list:
> > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
> >
> > or to administer your membership from a web page, go to:
> > http://www.freelists.org/webpage/si-list
> >
> > For help:
> > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
> >
> > List archives are viewable at:
> >               http://www.freelists.org/archives/si-list
> > or at our remote archives:
> >               http://groups.yahoo.com/group/si-list/messages
> > Old (prior to June 6, 2001) list archives are viewable at:
> >               http://www.qsl.net/wb6tpu
> >
> >
> >
> 
> ------------------------------------------------------------------
> To unsubscribe from si-list:
> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
> 
> or to administer your membership from a web page, go to:
> http://www.freelists.org/webpage/si-list
> 
> For help:
> si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
> 
> List archives are viewable at:
>                 http://www.freelists.org/archives/si-list
> or at our remote archives:
>                 http://groups.yahoo.com/group/si-list/messages
> Old (prior to June 6, 2001) list archives are viewable at:
>                 http://www.qsl.net/wb6tpu
>
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field

or to administer your membership from a web page, go to:
http://www.freelists.org/webpage/si-list

For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field

List archives are viewable at:     
                http://www.freelists.org/archives/si-list
or at our remote archives:
                http://groups.yahoo.com/group/si-list/messages 
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu

Other related posts: