Re: [model selector] keyword

Roland:

I do not think we intended that the reserved words be used with
[Model Selector]. As it stands, it looks like they could be
used. We will need to raise this question as a clarification
issue.

As an alternative, the same effect could be accomplished by
using a Terminator model to accomplish the same effect -
a low resistance to ground or power for GND or POWER, and
a high resistance for NC.

In your example below, the [Model Selector] does not undo
the differential association that may exist for the differential
driver. Either the pins 19 and 20 will always be differential
or be single ended based on the [Diff Pin] keyword.

Best Regards,
Bob Ross
Interconnectix

> From: Roland Chang <roland_chang@pmc-sierra.bc.ca>
> To: "'ibis-users@vhdl.org'" <ibis-users@vhdl.org>
> Subject: [model selector] keyword
> Date: Mon, 7 Jul 1997 15:25:57 -0700

> Hello all,

> I was wondering, in the use of the model selector keyword, can one list
> POWER, GND, and NC?
> The reason I ask, is that in the case of pins that are usable in various
> modes, it often involves grounding, or leaving certain other pins
> open(NC).

> thanx,

> roland
> ******************************************
> Roland Chang ext. 2647

> PMC-Sierra
> Applications Department
> 105-8555 Baxter Place
> Burnaby, BC
> V5A 4V7
> Tel: (604) 415-6000

> email: chang@pmc-sierra.bc.ca
> ******************************************

> eg:

> [Pin] signal_name model_name R_pin L_pin C_pin
> .
> .
> .
> 9 CLKI crystalbuf
> 10 CLKO crystalbuf
> .
> .
> .
> 19 IN(+) PECLbuf
> 20 IN(-) PECLbuf
> .
> .
> .
> [Model Selector] crystalbuf
> NC |default, CLKI, CLKO attached to a crystal
> pc5x03 |if CLKO left open (NC), feed external clock signal into CLKI

> [Model Selector] PECLbuf
> PECL_diff |default, IN(+), IN(-) function as PECL differential
> inputs
> PECL_single | IN(+) as single sided PECL, decouple IN(-) to ground.
> TTL_single | IN(+) as single sided TTL, IN(-) to ground.
> GND

 
Received on Mon Jul 7 18:07:37 1997