Thanks a lot, I am an idiot, I forgot the pullup, ....
It works now :-)
Kroko
----- Original Message -----
From: "Chris Wilkson" <ecwilkso@xxxxxxx>
To: <stella@xxxxxxxxxxx>
Sent: Sunday, January 12, 2003 10:50 AM
Subject: Re: [stella] Chip Select Line
> Is the 7407 inverting or non inverting? I think it's non-inverting, which
> is what you'd need. But it definitely has open collector outputs. Did
you
> use pullup resistors on the outputs? It won't work without connecting a
> pullup resistor from the output to VCC.
>
> -Chris
>
> On Thu, 9 Jan 2003, Kroko wrote:
>
> > Hello !
> >
> > I have made a little testing with an original PacMan ROM chip.
> > I made all the lines available for measuring the signals.
> >
> > If I connect all lines to the PacMan ROM, as in the original cartridge,
> > everything works fine.
> >
> > What I did now is, that I connected the A12 line to an 7407 buffer and
from the
> > output of that buffer back to the CS line o the ROM. It is not
inverting, so it
> > should work. But it doesn't. Why not ?
> >
> > What are the timing requirements for the A12 line ? What am I missing ?
> > It should work, shouldn't it ?
> >
> > Kroko.
> >
> >
> >
> >
> >
>
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