Re: Oric Drives

On 2005-07-28, Twilighte <twilighte@xxxxxxxxxxxxxx> wrote:

> Have just finished making up coiled lead between "Oric PC" and
> Keyboard. Have also found some nice pre-ribboned 25 way d connectors
> i'll use for each side.
> I know you said 15 way, but i'm using what i have and what i can get
> away with from work.
> I have been thinking about the keyboard. Would it drain too much power
> from the keyboard curcuit if i add an LED (with resistor) to the +5v
> connection?
>
> This way i could tell when everything is connected.

The cable is rated at 250 mA. An LED with a 470R resistor in
series will sink about 10 mA so that should be OK.

> I'm still not too keen on using the extra line for a reset button, i'd
> be more inclined to use it as an audio line to a socket for headphones
> or for the Cold Reset (I very rarely use soft-reset since i'm working
> in machine code, and when a crash occurs, it really crashes! ;) ).

The audio line would probably carry several orders of magnitude
more power than the data lines. Thin wire... crosstalk...
inductive load with a fragile CMOS chip nearby... no bypass
cap... It might work but I wouldn't be surprised if there were
problems.

*RES has a fairly low input impedance due to the pull-up on the
motherboard ; it should not be too sensitive to induced noise.

--
André Majorel <URL:http://www.teaser.fr/~amajorel/>
(Counterfeit: civutyp@xxxxxxxxxxxxxxx sakud@xxxxxxxxxxxxx)
"J'baiserai la France jusqu'à ce qu'elle m'aime." -- Un rappeur
.