mattislind at gmail.com
Tue Feb 21 14:41:27 CST 2017
tisdag 21 februari 2017 skrev Jecel Assumpcao Jr. <jecel at merlintec.com>:
> Jim Brain wrote:
> > As a function of "give a man a fish, you feed him for a day; teach a man
> > to fish, you feed him for all time", I dloaded Logic Friday, and figured
> > out a quick way to read the two 16L8 (combinatorial only) PALs on the
> > board with my EPROM reader (cue duct tape and baling wire snickers).
> Don't forget that 16L8 means 8 logic outputs and 16 inputs even though
> at first glance there only seems to be 8 inputs. That is because every
> output is also an input and can possibly be just an input by forcing the
> three state option.
Right now I am in the situation of having a 16L8 with unknown program so I
have been thinking (and googling) to find a solution. I have come to the
conclusion that this device has to be considered as 262144 by 8 ROM. 18
bits address space because it has 8 three state outputs (six of them may
act as inputs) which has to be probed in what way they are active driving
or not and then 10 inputs. I was thinking of driving the outputs through a
1k or so resistor and then reading back the outputs.
The inputs are of course driven as usual. Then I need to write some small
piece of software to deduce the OE pin values and minimise the equations
using some program mentioned above in the thread.
I have seen someone making a small device to do this.
Unfortunately the software doesn't seem to be available any longer. Anyone
that has it? It would definetely save me some time.
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