Documentation for VDHL source code of "Resurrector"
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This code originates from the Prometheus upgrade project.
It is a 1:1 translation from Altera legacy HDLs to modern 
VHDL code. 

The projects (PCIL and PCIH) are targeted at Xilinx CPLDs, 
namely the XC95144XL series.

Both projects have been carefully translated and simulated, 
but never made it into real hardware (I have PCB layouts for
such a card "on ice", so in case, I can make this public too on
request).

Please carefully read the license.txt file enclosed in this
package.

Please use Xilinx ISE 14.6 for the first step. More modern 
versions may work, too.

In case of questions - ask me. It may take some time for me 
to answer, as I have always some nerdy projects going on, and 
last, but not least, some family business (consider this as NMI).

Coding conventions
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All port signals carry "_IN", "_OUT" or "_INOUT" at the end, 
to designate signal flows (except top level entities, I assume
that you are familiar with Zorro III and PCI, or at least you
want to get to).

Top level entity signals starting with "Z_" target the Zorro III
bus, "P_" the PCI bus, and "I_" signals serve as interconnection 
between PCIH and PCIL CPLDs.

PCIH CPLD
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This CPLD acts as Zorro III autoconfig slave, and takes care of
PCI bus accesses. In addition, it features a PCI arbiter which
is crucial for mixing Zorro III and PCI bus actions.
Don't be confused - the real Zorro III access is handled in PCIL
CPLD.

PCIL CPLD
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This CPLD takes basically care of all low level bus timings.
It seems quite simple, but has a few potential pitfalls.
Take care especially on how the /SLAVE latch is being constructed,
the XC95144XL series doesn't have hardware latches, and while it 
is simply to get all kinds of unwanted latches in VHDL, it's not 
so straight forward to get a fully functional latch if your really
need it :)

And at the end...
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Have fun. I'm happy if you can use this code to better understand 
Zorro III and PCI. 
For me, the Amiga hardware teached me the basics of my job, and 
I'm happy every time to see that design approaches made in the 80s 
still work perfectly nowadays, be it in space, or on the ocean floor.

Thanks, Dave.

Michael Boehmer  (mboehmer@e3b.de)   2018.12