6502 bus timing for PBI device

As mentioned earlier, I'm looking at building a PBI device. I'm thinking
of using a PIC18F4455 microcontroller connected to the bus. I'm concerned
about whether this chip is actually fast enough, so I need to know the
exact timings of the 6502's usage of the address bus. If it's fast
enough, this single chip can read the signals on the Atari's bus, and
emulate RAM and ROM, as well as provide USB connectivity. All for a five
dollar chip!

How far into the cycle do I have to wait to read the address bus? The
signal on PHI2 is low during the first half of the cycle. My
understanding is that for memory reads, what matters is what is on the
data bus at the end of the cycle (when PHI2 goes from high to low). How
early can I trust the address to figure out what data to send?

If the chip in question isn't fast enough, they're announced some similar
16-bit microcontroller chips that should do the job, and I haven't looked
to see what other companies are selling.


Also, if anyone knows where to get a 50-pin socket to build a PBI device
with, that would be nice. I think the pin width is the same as for ISA
sockets, so I'm thinking one option is to desolder some off of an old
motherboard and then cut them down from 68 to 50 connections, but it would
be much nicer to start with the right connector.
.

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