Address Bus - Implementation

Implementation

Early processors used a wire for each bit of the address width. For example, a 16-bit address bus had 16 physical wires making up the bus. As the buses became wider, this approach became expensive in terms of the number of chip pins and board traces. Beginning with the Mostek 4096 DRAM, address multiplexing implemented with multiplexers became common. In a multiplexed address scheme, the address is sent in two equal parts. This halves the number of address bus signals required to connect to the memory. For example a 32-bit address bus can be implemented by using 16 wires and sending the first half of the memory address, immediately followed by the second half.