Is there a good digital designer out there

[craig-1]

Is there a good digital design engineer out there?????To help me solve some digital design problums

[Robert Reed]

A high is a logic 1, a low is a logic 0. Putting these together in the right sequence, you can build anything you want. Any other questions?

[Ron H]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by ROBERT REED:
A high is a logic 1, a low is a logic 0. <snip><hr></blockquote><p>In active high logic. <p>[ July 16, 2005: Message edited by: RonH ]</p>

[philba]

man, and I've been accused of being hard on people...<p>[ July 16, 2005: Message edited by: philba ]</p>

[Gorgon]

Hi Craig,
Email me your problem description, and I'll take a look.<p>Phil,
I agree with you in this.
A lot of hot air is blowing on the road to Ridicule!<p>TOK

[Robert Reed]

Sorry Craig
Reply was intended in good humor.Just could't resist the opening presented to me

[Robert Reed]

<p>[ July 17, 2005: Message edited by: ROBERT REED ]</p>

[philba]

even though I tweaked at you, I agree that postings like that are ripe for criticism and ridicule. Empty requests for help are but one kind.

[HighFrequency]

I'm not to shabby in the Digital Department either. If you need a third pair of eyes, give me a shout.

[Dean Huster]

"In active high logic."<p>I would prefer the phrase, "In positive logic."<p>"Active HIGH" or "active LOW" can describe the appropriate condition (circuit produces the desired output or activates with a logical HIGH or a logical LOW respectively) for either positive or negative logic.<p>A lot of folks that I run into think that just because something activates on a logical LOW (e.g., the output of a 7447) that it's negative logic, so I don't like to see those terms interchanged.<p>Dean

[jimandy]

It's interesting that when we see a topic started with such an ambivalent question, we rarely see the starter return to the thread. A rare exception may be found in the topic "schmidt trigger" [sic] where the starter has returned with a superambivalent question.

[philba]

probably because once the usual suspects are through with it they are afraid to be seen...

[paco3024]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by RonH:
<p>In active high logic. <p>[ July 16, 2005: Message edited by: RonH ]<hr></blockquote>
if in the digital universe there is only 1's or 0's where is the tristate world?

[Dean Huster]

Ah, but Tristate (a National Semiconductor tradename, three-state logic is the generic term) is not trinary logic, but a non-logical, high-impedance state in binary logic. Although it occupies a place in a typical truth table to argue its effects on the device, the output state is neither one, nor zero, but a non-committal high impedance that can be made HIGH or LOW by another device connected to the same line, effectively allowing the Tristate device to disconnect from the output line.<p>I might add that I did design a true trinary serial comm system back around 1984 where I had a logical LOW (0v) logical HIGH (+5v) and a third state (+10v) that was used to initialize the serial sequence. By feeding the serial signal to a pair of properly-biased CC transistor circuits simultaneously, the regular TTL levels were passed one direction and the +10v logic pulses another, to be converted back to standard TTL logic. At the time, it was a better solution than using some kind of long TTL HIGH to start the serial string. "At the time" being at the low end on the learning curve for me and serial digital communications!<p>Dean<p>[ July 24, 2005: Message edited by: Dean Huster ]</p>

[yesiamwds]

Kind of reminds me of trying to figure out whether 32 deg F. is melting or freezing. I personally like the logic that hovers in the 2.5vdc area of a 5vdc digital system.<p>WS (used to be from Rolla, Mo....now in NYC)