Adding Input to the IO Sub-Circuit

To add an input port I had to move the address out the output port and memory address to 0xE. The input port will use memory address 0xF but the memory select will be disabled:

Here is the updated top level schematic:

The binary counting program now reads the increment value for the input port upon start up. Therefore the input should be set before reset and run.

Here is the program:

Note: Line 9 (Jump 6) is redundant.

Am I going to build this CPU

No, the main purpose of the project was to learn LogiSim and to try out a CPU hardware control logic system.

Fixed the logi7400ic.circ library for both the 74161 and 74173 now.

AlanX