[ale] OT: Router for sale

[Mike Panetta]

On Sat, 2003-01-25 at 16:14, Marvin Dickens wrote:
> On Sun, 2003-01-26 at 02:24, Mike Panetta wrote:
> > That would work except for 2 problems... 
> > 
> > 1. The current produced by using a multimeter in "Continuity" mode (its
> > really a real low ohm setting, with a beep) may very well be enough to
> > kill the IO lines of todays 3.3V (or lower) processors.
> 
> Who made the Multimeter that your using and how many decades old is
> it...?... No multimeter I use is gonna put out anywhere near the
> amperage necessary to smoke a chip. Voltage is harmless when amperage is
> low (Basic physics...). All modern multimeters use extremely low
> amperage with very long wave forms.

What do wave forms have to do with anything?  The output of the
multimeter should be DC when its in continuity (resistance) mode anyway.
When a chips IO pin is only spec-ed to accept 3.3V and you apply more
then that to it, it has a chance to get damaged.  And the current is not
too limited when your in continuity mode (because its a low resistance
setting) so that it can actually measure the resistance.  I have no
empirical evidence as to what it is, but I am sure it could easily be
measured, and if its over 20mA it has a chance of killing the IO pin.  

> 
> On as side note, if the amperage is high enough, less than .5V can kill
> a person or even an elephant. Electricity can kill if the amperage and
> the voltage is low, but the current is at the right frequency.

That is irrelevant to what I was discussing.  I was talking about
damaging an IC not a person...  

> 
> 
> > and...
> > 
> > 2. The chip is more then likely a BGA package.  Have fun finding the
> > pins on that one...  Not all boards have one VIA per pin for BGA
> > packages, it may not be necessary for the particular layout of the
> > board.
> 
> Back when those things were made, BGA packaging (As far as the number of
> lines that could pick/place BGA) was limited. At that time, BGA was used
> when thermal was an issue. With this processor,thermal is not an issue.
> Look at the specs to the chip. Further, the chances are it's not a BGA
> unless is was manufactured before 24 months ago. The facts are that less
> than 5% of all silicon produced before about 24 months ago was packaging
> other than BGA. Even today, less than 9% of all silicon produced is in
> BGA packaging. 

If its a Motorola PPC chip there is a 100% chance of it being a BGA.
Just take a look at their web page.  There is also a pretty high chance
of it being a BGA if its an ARM chip as well.  They are all going to BGA
packages because they are smaller, and have a larger number of pins in a
smaller package to give you higher IO counts.  Almost every high pin
count device on a motherboard these days is a BGA. Just take a look for
yourself.  I do not care for statistics, I only care about what I
observe.  And I am observing more and more chips going to the BGA type
package.  Hell you can even get resistor networks in BGA packages now. 
I do not know where you got your numbers from, but as far as I am
concerned more then 9% of all the chips I care about (not all the chips,
but only a subset of the "all silicon" number you quoted above) are
BGA's now.  Almost every 32bit processor Motorola makes is in a BGA, and
even a large portion of Intel's embedded processors are BGA.  This is
making it harder and harder for the hobbyist to reverse engineer or
otherwise develop things using these chips.  I should know, I am one.  I
of course also use these chips for a living (I can even say I design PC
Boards for a living now, but only using 8 bit processors, so its not
relevant to this discussion...), so its not like I am discussing this
from a hobbyist perspective.

> 
> 
> This is the sector of the business where I make my living. I would never
> give out advice like I did if I even remotely thought it would harm
> someone else's property.

I was not trying to imply you were knowingly giving out information that
could possibly harm someones property, I am just saying you may have not
known.

> 
> 
> Best regards
> 
> 
> Marvin Dickens

Mike

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