Re: [CAD_CAM_EDM_DRO] TTL 101 was Re: troubleshooting help

Ballendo,

Yes I'm aware the actual voltages are not 0 and 5 but just used
those to state my question. Probably should have used the terms
'high or low' instead.

Thanks for everone's input. My goal is to come-up with some dro
software which will run on a loptop with the old 'standard' p-port
by using the status pins is input. Lindsay's software would work
if the code could be changed to look at the status pins instead
of the data pins.

I'm not a C++ programer so it is a little beyond my capabilities.

Bob


At 12:39 PM 2/19/02 -0000, you wrote:

>Bob,
>
>Although many are saying 0v and 5v, that is not "really" correct.
>
>What TTL** WILL guarantee is that a logic "0"(Lo) will be LESS
>than .8v and a logic "1"(HI) will be MORE than 2.4v
>
>I know that Jon, Alan, and the other electronics guys know this
>already. We casually speak of 0 and 5v(knowing the "truth"), but
>since many on this list do NOT know already; and may be using a meter
>to "check", I thought it would be worth mentioning...
>
>Many times a "measured"(typical) HI will be about 3.3v, and a
>measured Lo about .4v...
>
>**Transistor-Transistor-Logic. The basis for the original IBM PC
>parallel port circuitry. Nowadays the ports use different electronic
>means to accomplish the same ends results.
>
>Hope this helps.
>
>Ballendo
>