memory mapped I/O
memory mapped I/O
(architecture)The I/O devices are addressed at certain reserved addressranges on the main memory bus. These addresses cannottherefore be used for RAM. Motorola and Mostecarchitectures, among others, use memory mapped I/O.
Video cards and other cards with on-board memory might beaccessed in this way though the term applies not just todevices containing memory but to any device connected to thememory bus. Accessing the devices usually consists of readingand writing certain built-in registers though sometimes themere presence of a particular address can trigger the device.