Subject: Re: [stella] Chip Select Line From: Chris Wilkson <ecwilkso@xxxxxxx> Date: Sun, 12 Jan 2003 04:50:57 -0500 (EST) |
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. > > > > > ---------------------------------------------------------------------------------------------- Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
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