On Saturday 09 February 2002 04:01, Jeff Newmiller wrote:
> The altered states to start to come into focus. :)
hehe, kind of scary, eh?
> This is a cmos logic device.. not a power driver. It will not burn
> out any resistor. You often see resistors inline to limit current
> (say, for LEDs or transients from off-board inputs), but these are
> NEVER zero ohm resistors.
I will have to agree with that, a real small diode would be more
standard there, I've never seen a "0 ohm" resistor?
> A zero ohm resistor is a piece of wire. It is not a fuse. I would
> recommend that you re-read Charles Steinkuehler's analysis for the
> most likely function of this (most likely not installed) piece of
> wire.
Yep, I did and what you are saying makes sense. Why would you
call a piece of wire (a jumper) a resistor? It seems that you would
call it "J8" or something or something along those lines. In any case,
what "R8" does, as Charles noted, takes the Wait# from the LD017_A0
to pin 30 (ground) on the controller. Mike said the tech told him that:
"They use a hardware solution shunting R8 to ground", which indicates
to me that R8 was designed to be a component besides a piece of wire.
A shunt is typically a resistor or an inductor coil. A piece of wire
would work, but probably not what the design team had in mind.
Now, what the design(ers) had in mind, I won't necessarily guess at.
> It seems to me that tying reset low would prevent the interface
> circuitry from working... that is, the device would be write
> protected, but it would also be read protected, so if it lost power
> you would have to physically be there to enable reboot. This would
> _not_ be ideal.
No, I proved that by simply trying it. Logically, you make sense, but
maybe that is why noone has gotten a typical ATA device to work
this way in the years that it has been attempted. I proved that setting
pin 1 to ground does _not_ disable read capabilities of the drive or
the ability to communicate the Low-level hardware (BIOS). As one
of my old high school math teachers kindly beat in my head,
"Sometimes 'PIAGO' is the only way to tell for sure"!
(PIAGO ---> Plug it IN and Grind it Out)
I'll try it with some other boards and ATA devices as soon as I get
around to Syslinux'ing any of them, if noone else feels the desire
to taking a chance on destroying some 7+ year old hardware.
I find much of it by trash cans or at a DAV store for under $10,
so I can afford to destroy one or two if it will benefit us.
--
~Lynn Avants
aka Guitarlynn
guitarlynn at users.sourceforge.net
http://leaf.sourceforge.net
If linux isn't the answer, you've probably got the wrong question!
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