16 min read

Buses: Data, Address and Control

The three buses that carry values, locations and signals — and how bus width decides how much memory can be used.

What Is a Bus?

The width of a bus is the number of wires in it — how many bits it carries at once. A wider data bus moves more data in each clock tick, so transfers are faster. A 64-bit data bus moves 8 bytes at a time; a 32-bit bus moves 4. A wider address bus can point to more memory locations. With n address lines, the CPU can address 2ⁿ locations.

Practice

A processor has a 12-bit address bus. How many memory locations can it address?

Your answer

What Is a Bus?

Bus Width

The width of a bus is the number of wires in it — how many bits it carries at once. A wider data bus moves more data in each clock tick, so transfers are faster. A 64-bit data bus moves 8 bytes at a time; a 32-bit bus moves 4. A wider address bus can point to more memory locations. With n address lines, the CPU can address 2ⁿ locations.

Practice

A processor has a 12-bit address bus. How many memory locations can it address?

Your answer