30 Jun
2008
30 Jun
'08
7:54 p.m.
On Monday 30 June 2008 21:13, Eric Smith wrote:
How would logic levels work otherwise?
They're independent, though, in the sense that loads on one will not af=
fect=20
the regulation of the other.
Am I missing something here of have Commodore managed to make a ground
trace with no inductance (in violation of the laws of physics)?
One of Vonada's laws is 'There is no such thing as ground'. It's not at
all un common for there to be significant ripple on a ground connection
(measures wrt some other point on the _same_ trace!) doe to the
inductance of said trance. And it's a real problem in either high-speed
or low-noise-analoge circuitry (if the device happens to use both
high-speed digianl and low-noise analogue circuitry, you've got a lot of
work to do...)
In the cae of the C64, it's very likely that loads on one of the 5V lines
could affect the other line trough the common ground.
-tony
Roy wrote:
> Because they really need to have those two +5VDC supplies separate an=
d
independent of each other.
They aren't independent. They share a common ground reference.