Computer I/O architecture defines how processors exchange information with memory, peripherals, communication devices, and physical hardware. Memory-mapped I/O provides a common programming model in which peripheral registers occupy processor address space and can be accessed through normal load and store operations. Address decoding selects the appropriate device, while device drivers hide register addresses, bit fields, timing requirements, and hardware-specific behavior behind structured software interfaces. GPIO extends this model to configurable digital pins, with registers controlling direction, input state, output values, alternate functions, and interrupt conditions. Embedded systems combine digital I/O with serial communication, timing, and analog conversion. SPI, UART, and I2C transfer data through compact serial connections, while Bluetooth modules can replace wired serial links with low-power wireless communication. Timers use free-running counters and compare channels to measure or generate precise time intervals, while interrupt-driven processing avoids the inefficiency of continuous polling. ADCs convert continuous analog voltages into digital samples, DACs perform ...