does a reverse-engineering EDA tool exist?

[Christian Corti]

On Thu, 25 Oct 2018, Guy Dunphy wrote:
> Keep the objective in mind. What you want to end up with is a schematic, 
> that is laid out in a way that aids comprehension of how the circuit 
> works. Typically this means overall left to right functional or power 
> flow, with separate functional blocks visually separate, visual emphasis 
> where appropriate, and so on. Something like the original designers 
> drew, if they were any good.
>
>
> When you have only a PCB and want to reverse engineer the schematic, the 
> tasks are:
[...]

This is actually the way how I reverse-engineered the MINCAL 523. Identify 
the address and data busses, registers, latches, functional sections (e.g. 
ALU, interrupt related, I/O, ...) and put that all together. And yes, it 
involves a lot of paper and pencil work, and that is faster and much more 
intuitive than doing it with the computer.
To create the schematics I use gschem from the gEDA suite.

Currently, I have started to reverse-engineer the Digico computer. I have 
only looked at the CPU board so far, but that leads to a dead-end as I am 
not able to unambiguously identify the address and data busses. So I have 
to continue with the front panel, start with the display/keypad where you 
can select the individual registers for entry/display and go back to the 
front panel connector back to the CPU board. There, I hope to find the 
instruction register and continue with the instruction decoder section.

Christian