I finished the ALU (all 8 bits) and the test-board yesterday. It contains 355 transistors without the test board.

In all it took less then two days to construct and trouble-shoot (not including the small boards).

It is interesting to note that the ALU only had one short while the test board had two LED's soldered in backwards and a short.


The back side of the ALU;


The 34 pin connector is wired as below;

pin out alu 001.jpg

The six functions are not encoded so if more then one is selected at a time the functions are calculated and the the results are OR'd together

(I don't think this property has a practical use).


Here is the test-board (just light's and switches);




And finely the block diagram;

Scomadic ALU 001.jpg