backing up PAL chips

Alexandre Souza wrote: If the device is not registered, then it's purely combinatorial and you can map all the cumzouta's by stimulating all the gazinta's. Brute force. But, this can then be algorithmically reduced to a set of simple equations. If the device is registered AND THERE IS NO BURIED STATE, it's a similar process to the above -- except now all of those registered outputs are also inputs to the array. The added trick is that you need to keep track of how to *get* to a particular state in order to have that set of inputs the way you want them as you probe the array. The easiest way I have found to do this is to just build a map of each (present state, inputs) condition and record the observed "next state" that results. Initialize this to "unknown" for each possible set of state and inputs. When you find yourself in a state, see which inputs have not been tried. Try one. Record the result. Repeat. If you find yourself in a state that is entirely mapped, pick a set of inputs that will get you to some OTHER state with some as yet unknown inputs. There are deterministic algorithms that will tell you if you can get the whole process takes a few seconds on a slow PC :> (assuming you have direct access to the inputs and outputs of the device)