It depends on the size of the address bus, which is often different than the size of the data bus.
- If the address bus were 8 bits, then you could address 256 locations.
- If the address bus were 16 bits, such as in the 8085, then you could address 65,536 locations.
- If the address bus were 20 bits, such as in the 8086/8088, then you can address 1,048,576 locations.
