Each location in the memory space has a unique, sequential address. The address of a memory location is used to specify (and select) that location. The memory space is also known as the address space , and how that address space is partitioned between different memory and I/O devices is known as the memory map . The address space is the array of all addressable memory locations. In an 8-bit processor (such as the 68HC11) with a 16-bit address bus, this works out to be 216 = 65,536 = 64K of memory. Hence, the processor is said to ...