That's exactly what I am doing.

And your fix worked great! Thanks.

I have to say, I also NAND R/!W to the /CS signal as well, because I only want to use the data when I am writing to the output address:

I am more or less following / using the schematic from the 6502 primer at (http://wilsonminesco.com/6502primer/addr_decoding.html) and using the /CS for the 6522s ANDed with PHI2 as the clock signal for a SN74LS273N.

It looks okay, except for the fact that the 74273 is too fast (typ switching high ...

What exactly do you mean with "qualify chip selects with PHI2 high"?

I am not a native speaker and haven't heard the term "qualify" in this context before.

Thanks, I haven't read the primer. Seems like a lot of information there. I'll have to study that.

I'll go a step back and make my design simpler.

When I measure now with a multimeter, I get 0.3-0.7V, not 1.8.

I did see the 1.8 earlier on an osscilloscope.

Attached my design.

I try to create some kind of W65C02S based computer, and until now, it worked pretty well, but I ran into some snags now. I have no idea how to continue, so I'll just tell what I tried and perhaps somebody can give me some hints or tips.

The design is just the 6502, with 32kB RAM and 32 kB ROM ...