Brian Mury:
> You should see +12 volts or -12 volts (actually anything between
3
> and 15 meets the spec, but you'll usually see somewhere around 12).
> Negative voltages are high, positive voltages are low,
Tim:
Other way around... A high (digital 1) is a positive voltage, a low
(digital 0) is a lower or negative voltage (i.e. less than the 1's
voltage, whether it be zero or below zero).
All digital logic is this way. There are cases where the low signal
is the active state (i.e. a 0 is true and 1 is false), called
"negative logic," or "active low," but it's still a case of
1's
voltage is greater than 0's. It's the meaning of 0 and 1 that's
inverted.
Scratch that... Serial *data* lines are backwards.
Gawd I hate negative logic.
--
[tim@localhost ~]$ uname -r
2.6.27.25-78.2.56.fc9.i686
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