<architecture> The use of the same instructions and bus to
communicate with both main memory and input/output
devices. This is in contrast to processors that have a
separate I/O bus and special instructions to access it.
The I/O devices are addressed at certain reserved address
ranges on the main memory bus. These addresses cannot
therefore be used for RAM. Motorola and Mostec
architectures, among others, use memory mapped I/O.
Video cards and other cards with on-board memory might be
accessed in this way though the term applies not just to
devices containing memory but to any device connected to the
memory bus. Accessing the devices usually consists of reading
and writing certain built-in registers though sometimes the
mere presence of a particular address can trigger the device.
(1997-04-14)
Nearby terms:
memory location « memory management « Memory Management Unit « memory mapped I/O » memory protection » memory smash » Memory Type Range Registers
