(10-20-2019, 03:58 PM)Koyarno Wrote: What is a PGA?
PGA = programmable gate array, there's a common microchip called an FPGA or "field-programmable gate array," because it can be changed in the field. Some might also call it a PLA (programmable logic array).
It's basically a catch all term for a device that has configurable logic gates, so that you can decide for an intersection of inputs what logical operation you want that intersection to perform. Kind of like a programmable truth table. Given a number of inputs i, the number of outputs is (edit) : 2^i. For each combination of different binary inputs, we can set the output to be either 1 or 0, depending on the switches we set in the PGA.
Taking a 2-input example, there are 4 possibilities, 00, 01, 10, 11. With a PGA, you can decide for each of those possibilities what you want the output to be (0 or 1). So by changing our PGA we could make it an OR gate, an AND gate, an XOR gate, or something that doesn't even have a name, like the following truth table:
(which translates in english to something like "Neither set, or the first one set")
AB|Output
00|1
10|1
01|0
11|0