Since the question came up in the German forum:
There are some limitations:
From
http://dreamjam.co.uk/emuviews/readpal.php
This approach does not work for the following devices:
All registered PAL devices. (PAL16R4, PAL16R6, PAL16R8, etc.)
All GAL devices configured to be registered. (GAL16V8, etc.)
PEEL devices (18CV8, etc.) which have a different architecture than PALs / GALs.
Non-PAL or GAL devices (82S153, PLS153, etc.) which have a different architecture and pinout than PALs / GALs.
In general all registered devices cannot be dumped, which includes purely combinatorial devices that implement latches through combinational logic
Specific limitations for GAL16V8
A GAL16V8 can be configured as combinatorial, registered, or mixed. Only purely combinatorial configurations can be dumped. To aid in identifying a registered configuration you may note that pin 11 (OE #) is tied to ground and pin 1 (CLK) is tied to a clock source or write strobe. However these types of connections are not reliable indicators of a registered configuration.
With simple PALs, you can quite easily determine logic equations that reflect the behavior of the chip in this way.
An example: An address decoder that delivers / CS1 at A11 / A14 = 1 and Ax = 0 and / CS2 at A11 / A12 = 1 and Ax = 0.
That is easy to recognize and you can determine the logic equations accordingly. There are enough systems that use a PAL16H8 in exactly the same way.
With the information you can sit down and determine appropriate logic equations and program a PAL (or GAL that is still available).
And now it's going to get creepy for some (ashes on my head):
With the read out data you could also program an EPROM or EEPROM and use it as a PAL replacement, at least if it is an old PAL. The inputs go to the address lines, the outputs to the data lines, /OE and /CS to LOW. And yes, I know that this doesn't always work for various reasons, but you can still try it out.
With the C64 there are corresponding attempts that work more or less well.
By the way, these are the PALs I'm talking about:
and many GALs are used in the same way (basically, a GAL16V8 can replace the PAL10H8, PAL12H6, PAL14H4, PAL16H2, PAL10L8, PAL12L6, PAL14L4, PAL16L2 and PAL16C1).
Here's above example again in a very simple way:
The same IC (a 74244) but only defines 5 inputs and 4 outputs:
The tester delivers the following file:
Entered in an Excel table, you can see the output enable signal on pin 19:
I am thinking about to also set the voltage supply via the menu, then you can reproach the tester for anything and later see how the chip behaved.
It is only a tool to go through all the input combinations and observe the outputs. With a little effort, under certain conditions, you can come up with suitable logic equations again.
