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valtih1978
Guest
Sun Oct 09, 2011 4:46 pm
I read on termination topics and they say that having Vtt equal to the
high-to-low transition level is a bad idea (tristated buses will
noise-switch all the readers and, thus, consume unnecessary power). Yet,
JEDEC prescribes using 1.25 Vtt for DDR, based on 2.5 volt SSTL_2
signaling. Why?
krw@att.bizzzzzzzzzzzz
Guest
Sun Oct 09, 2011 4:54 pm
On Sun, 09 Oct 2011 19:46:50 +0300, valtih1978 <do_at_not.email.me> wrote:
Quote:
I read on termination topics and they say that having Vtt equal to the
high-to-low transition level is a bad idea (tristated buses will
noise-switch all the readers and, thus, consume unnecessary power). Yet,
JEDEC prescribes using 1.25 Vtt for DDR, based on 2.5 volt SSTL_2
signaling. Why?
Minimum terminator power? P=V^2/R
valtih1978
Guest
Sun Oct 09, 2011 6:40 pm
Quote:
Minimum terminator power? P=V^2/R
consume more to save more!
krw@att.bizzzzzzzzzzzz
Guest
Sun Oct 09, 2011 9:03 pm
On Sun, 09 Oct 2011 21:40:37 +0300, valtih1978 <do_at_not.email.me> wrote:
Quote:
Minimum terminator power? P=V^2/R
consume more to save more!
Huh? With the terminator in the middle, you save half the power (twice as
many lines, on average, 1/4 power each). The I/O obviously can't have an
issue being "hung up" in the middle.
valtih1978
Guest
Mon Oct 10, 2011 10:12 am
http://web.cecs.pdx.edu/~greenwd/xmsnLine_notes.pdf explains the "issue":
"For three-state buses, the Théven in equivalent voltage, VThev, may be
chosen to yield a valid logic level when the bus is not being driven. It
is especi ally important in this case to choose a voltage that is not
close to the switching threshold of the receivers, lest they draw
excessive current or oscillate."
krw@att.bizzzzzzzzzzzz
Guest
Mon Oct 10, 2011 3:03 pm
On Mon, 10 Oct 2011 13:12:33 +0300, valtih1978 <do_at_not.email.me> wrote:
Quote:
http://web.cecs.pdx.edu/~greenwd/xmsnLine_notes.pdf explains the "issue":
"For three-state buses, the Théven in equivalent voltage, VThev, may be
chosen to yield a valid logic level when the bus is not being driven. It
is especi ally important in this case to choose a voltage that is not
close to the switching threshold of the receivers, lest they draw
excessive current or oscillate."
....or are disabled when in the tristate condition. You know more than the
memory (bus) developers?
krw@att.bizzzzzzzzzzzz
Guest
Mon Oct 10, 2011 3:04 pm
On Mon, 10 Oct 2011 13:12:33 +0300, valtih1978 <do_at_not.email.me> wrote:
Quote:
http://web.cecs.pdx.edu/~greenwd/xmsnLine_notes.pdf explains the "issue":
"For three-state buses, the Théven in equivalent voltage, VThev, may be
chosen to yield a valid logic level when the bus is not being driven. It
is especi ally important in this case to choose a voltage that is not
close to the switching threshold of the receivers, lest they draw
excessive current or oscillate."
BTW, if you know everything, why are you here?
valtih1978
Guest
Tue Oct 11, 2011 8:24 am
Only those who do not understand experts ask questions. Those, who ask
to explain the reason behind expert decisions, should not ask the questions.
Rich Grise
Guest
Tue Oct 11, 2011 9:53 am
valtih1978 wrote:
Quote:
Only those who do not understand experts ask questions. Those, who ask
to explain the reason behind expert decisions, should not ask the
questions.
Have you ever gone outside and played "hide and go fuck yourself?"
The only stupid question is the one you don't ask.
And the most important thing anyone can learn in life is to question
authority.
Hope This Helps!
Rich
valtih1978
Guest
Tue Oct 11, 2011 10:42 am
It seems that giving answers to asked questions I make people crazy.
krw@att.bizzzzzzzzzzzz
Guest
Tue Oct 11, 2011 1:09 pm
On Tue, 11 Oct 2011 13:42:52 +0300, valtih1978 <do_at_not.email.me> wrote:
Quote:
It seems that giving answers to asked questions I make people crazy.
You asked the question, moron. If you think you know everything (you know
nothing), asking a question and arguing that your answer is correct (it's not)
is moronic.
Now, go away.
krw@att.bizzzzzzzzzzzz
Guest
Tue Oct 11, 2011 1:10 pm
On Tue, 11 Oct 2011 11:24:04 +0300, valtih1978 <do_at_not.email.me> wrote:
Quote:
Only those who do not understand experts ask questions.
....and then argue the answer? Moron.
Quote:
Those, who ask to explain the reason behind expert decisions,
should not ask the questions.
What a loon.
Rich Grise
Guest
Tue Oct 11, 2011 2:50 pm
valtih1978 wrote:
Quote:
It seems that giving answers to asked questions I make people crazy.
I am a mirror.
Michael A. Terrell
Guest
Tue Oct 11, 2011 3:44 pm
valtih1978 wrote:
Quote:
Only those who do not understand experts ask questions. Those, who ask
to explain the reason behind expert decisions, should not ask the questions.
Plonk
--
You can't have a sense of humor, if you have no sense.
valtih1978
Guest
Tue Oct 11, 2011 6:01 pm
Quote:
Those, who ask to explain the reason behind expert decisions,
should not ask the questions.
What a loon.
Stupid thing? But, this is what you taught me. BTW, next time you hear
anybody asking a question, do not tell him that he knows everything.
Only morons and loons may come to such conclusion.
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