Re: LVDS output pins of Altera Cyclone II

Hi Rob,

I know that I have to use the assigment editor to change the output type from LVTTL 
(default) to LVDS.

But when using LVTTL I always have access to the "output enable" of the output pin to tri-
state the pin. But this does not work when using LVDS output. 

The output register is always enabled (OE set to '1') when I look at the design with the 
RTL viewer.

This is a little bit strange because actually the Cyclone II parts do not have any "real" 
LVDS outputs. It is standard LVTTL and the LVDS voltage levels are generated by a specific 
set of resitors on the PCB.


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Why do you want to tri-state the LVDS outputs?


"tentacle" <onlyspam@online.ms> wrote in message 
news:3ebd3$45708bb0$54964b97$1398@nf16.news-service.com...
> Hi Rob,
>
> I know that I have to use the assigment editor to change the output type 
> from LVTTL
> (default) to LVDS.
>
> But when using LVTTL I always have access to the "output enable" of the 
> output pin to tri-
> state the pin. But this does not work when using LVDS output.
>
> The output register is always enabled (OE set to '1') when I look at the 
> design with the
> RTL viewer.
>
> This is a little bit strange because actually the Cyclone II parts do not 
> have any "real"
> LVDS outputs. It is standard LVTTL and the LVDS voltage levels are 
> generated by a specific
> set of resitors on the PCB.
>
>
> --
> --------------------------------- --- -- -
> Posted with NewsLeecher v3.7 Final
> Web @ http://www.newsleecher.com/?usenet
> ------------------- ----- ---- -- -
>