PCPI clone ready to ship

[Alex Freed <alex_news@mirrow.com>]

I got all the PCBs and the components and even assembled
a few boards myself - only 5 were requested, so no
professional assembly.

The prototype worked so well that I didn't expect any
trouble and got a nasty surprise when the boards just
refused to work with a 10 MHz genuine Zilog Z80. I even
thought I got the wrong parts for a few minutes. The
Sharp Z80-B rated 6 MHz works great at 7.3 MHz, but a
10 MHz Z80 doesn't!

The investigation resulted in noticing that my logic
assumed that IORQ became active after WR. This was not
true for the 10 MHz part. I looked at the spec document
and sure enough this is documented. 4 and 6 MHz parts
assert WR first, but not the faster versions.

I have updated the CPLD source on the web page.

I have also added a few pictures and instructions at
http://mirrow.com/FPGApple/Assembly.html

Some 7 or 8 extra boards are available if somebody made
their mind.

-Alex.