Subject: V/I table checking (from Kellee Crisafulli)

From: Kellee Crisafulli <[email-masked]>
Date: 16 Mar 94 01:28:24 EST

To: Jon Powel, Arpad, IBIS commitee
From: Kellee Crisafulli
Re: method to determine if V/I table is valid

Good point Jon and Arpad.

I had negelected to considered noise from systems where the data is being
sampled with a data acquisition system.  (oops)

Several things make it difficult to test for the wrong sign:
  - The data can change direction and be valid.
  - Only 2 points are required to have a valid table.
  - No particular voltage points are required.
    (there may or may not be data points at VCC or ground).

I have a new simplified method based on Jon's suggestion that should also work
with Arpad's data:

For each V/I table:
  1) Find the minimum and maximum voltage points (Vmin, Vmax) in the table.

  2) IF:The TYPICAL current corresponding to Vmax is less than the TYPICAL
        current corresponding to Vmin than the table is assumed to have
        decreasing current.
     ELSE: The table is assumed to have increasing current.

  3) Verify that:
        - Pullup      V/I table has decreasing current
        - POWER_clamp V/I table has decreasing current
        - Pulldown    V/I table has increasing current
        - GND_clamp   V/I table has increasing current

  4) If any table moves in the wrong direction flag as an error

  5) Another test we could consider is if the currents at Vmin and Vmax are equal
     then assume the data is a single point and thus invalid.  (This may already be tested
     I don't recall).

I would still like to get agreement on this by Friday if possible.

Here's hoping this IBIS_CHK egg is not broken,scrambled, or stolen by the big bad wolf.
Have a great day... Kellee

---

From: Don A Telian <[email-masked]>
Date: Wed, 16 Mar 94 14:01:13 PST

Howdy,

I'm glad you guys are working this issue.  Please remember that it takes an 
accepted BIRD to change the parser.  I thought I read about someone editing the 
parser on Monday (!?).  That's not going to happen, right?

Donald Telian
___________________________________________________________

I have a new simplified method based on Jon's suggestion that should also
-work
with Arpad's data:

For each V/I table:

  3) Verify that:

  5) Another test we could consider is if the currents at Vmin and Vmax
-are equal
     then assume the data is a single point and thus invalid.  (This may
-already be tested
     I don't recall).

Here's hoping this IBIS_CHK egg is not broken,scrambled, or stolen by
-the big bad wolf.
Have a great day... Kellee

---

From: "Hobbs, Will" <[email-masked]>
Date: Wed, 16 Mar 94 16:25:05 PST

Don, et al,

This has been referred to as an emergency BIRD, which has to be ratified.  The 
BIRD hasn't been generated yet, and the change to the parser will have to be 
benign (i.e., warning, not error).  The issue is that this is a common pitfall, 
and several feel we need to do something about it quickly.

Will

Howdy,

Donald Telian

For each V/I table:

  3) Verify that:

---

From: Don A Telian <[email-masked]>
Date: Wed, 16 Mar 94 17:15:21 PST

Will and ?,

Will one of the "several who feel we need to do something about it quickly" 
please let me know what the rush is.  Give me a call if you like, (916)356-5029.
 The monotonicity discussion has been around for a long time with no quick 
solutions.  I do not believe any change to the parser is benign, particularly 
one that creates new warning messages.

Thanks,
Donald Telian

--------------------------------------------------------------------------

Don, et al,

This has been referred to as an emergency BIRD, which has to be ratified.
- The
BIRD hasn't been generated yet, and the change to the parser will have to be
benign (i.e., warning, not error).  The issue is that this is a common
-pitfall,
and several feel we need to do something about it quickly.

Will

Howdy,

I'm glad you guys are working this issue.  Please remember that it takes an
accepted BIRD to change the parser.  I thought I read about someone editing
-the
parser on Monday (!?).  That's not going to happen, right?

Donald Telian

For each V/I table:

  3) Verify that:

---

From: Arpad Muranyi <[email-masked]>
Date: Fri, 18 Mar 94 13:51:18 PST

---------------------------- Forwarded with Changes ---------------------------
From: Don A Telian at SWCAD
Date: 3/16/94 5:22PM
To: Don A Telian at FMCCM4
To: Arpad Muranyi at FMCCM4
*To: Tim A Schreyer at JFCCM7
*To: [email-masked] at Internet_Gateway
*To: [email-masked] at Internet_Gateway
*To: [email-masked] at Internet_Gateway
*To: [email-masked] at Internet_Gateway
*To: [email-masked] at Internet_Gateway
*To: Tim A Schreyer
Subject: Re[3]: V/I table checking (from Kellee Crisafulli)
-------------------------------------------------------------------------------
So what are we checking for anyways?

Sign errors or monotonicity?  They are completely two different issues.
Arpad

Will and ?,

please let me know what the rush is.  Give me a call if you like, (916)356-502
-9.
-

Thanks,
Donald Telian

---

From: "Hobbs, Will" <[email-masked]>
Date: Fri, 18 Mar 94 13:53:06 PST

This is not about montonicity but V/I sign.  Other mail has already cleared this
confusion up, I thought.

Will