Nada - Program Counter and Memory

Design Description

The Program Counter is built using a 4-bit Register and a 4-bit Adder to increment (+1) automatically.

It has a Clock input to count and a Reset input to go back to zero.

I used a 16×4 ROM to store the instructions.

Stored Instructions in ROM:

| Address | Instruction | Meaning |

|---------|-------------|-----------|

| 0000 | 0000 | LOAD A |

| 0001 | 0001 | LOAD B |

| 0010 | 0010 | ADD |

| 0011 | 0011 | SUB |

| 0100 | 0100 | STORE |

Testing Results

Reset works: PC returns to 0000.

Clock works: PC increments correctly (0000 → 0001 → 0010 → 0011 → 0100...).

INSTRUCTION_OUT shows the correct instruction for each address.