# MyHDL and the NEXYS 2 Board/Combinational circuits

Establish basic parameters: a combinatorial logic circuit is a circuit built from logic gates where signals move exclusively from left to right so there are no cycles. The consequence of this is that no history is stored anywhere in the circuit; every signal is some function of the inputs along the left edge.

DeMorgan's theorem. Sum of products, product of sums, Karnaugh maps. Gray code.

Talk about examples of combinatorial circuits, including half-adders and full-adders, multiplexers, demultiplexers, ROM lookup tables, etc.

Show how a diode matrix can implement either a bunch of AND gates or a bunch of OR gates. Two diode matrices can be used to build a programmable logic array. Programmable ROMs were essentially big diode arrays where you could blow a fuse in the second matrix to take out a diode.