Information Buses

Inside a computer, components don't talk to each other directly. They communicate through buses — shared sets of wires that carry information across the system. There are three main types:

The data bus carries the actual values being processed. In an 8-bit processor, the data bus is 8 wires wide — it can transfer one byte per clock cycle. When the ALU computes a result, it places it on the data bus. When RAM is read, the value travels over the data bus to the accumulator.

The address bus specifies where data should come from or go to. It's a one-way street — the processor drives it to tell memory and peripherals which location it wants to access. A 16-bit address bus can address 65,536 unique locations.

The control bus carries command signals: Read, Write, Clock, Reset. When the processor wants to read from RAM, it sets the address on the address bus, asserts the Read control line, and the RAM places the data on the data bus. The control bus orchestrates the dance.

Practical example. To execute STA 100 (store accumulator to address 100): the processor places 100 on the address bus, the accumulator value on the data bus, asserts the Write control line, and on the next clock edge, RAM stores the value at address 100. Three buses, one operation, all coordinated by the control signals.