CPUtodevice

CPUtodevice is a term used to describe the set of mechanisms by which a central processing unit (CPU) communicates with peripheral devices and accelerators. It encompasses software interfaces, hardware buses, and signaling methods that enable the CPU to issue commands, transfer data, and receive status from devices.

Core techniques include memory-mapped I/O, where device registers appear in the system's address space; port-mapped I/O, where devices are controlled through dedicated I/O ports; and direct memory access (DMA), which enables devices to transfer data to or from memory with minimal CPU involvement. Interrupts, polling, and DMA completion signaling are used to coordinate data transfers.

CPUtodevice designs typically involve device drivers that translate generic OS I/O requests into device-specific operations, plus device controllers and buses such as PCIe, USB, or SPI. Modern systems use layered architectures with kernel-mode drivers and, in some cases, user-space drivers or virtualization layers to isolate and manage access to devices.

Applications vary from general-purpose computing with PCIe devices to embedded systems where microcontrollers manage sensors and actuators via MMIO registers. Performance considerations include latency, bandwidth, CPU overhead, and DMA efficiency. Security and isolation concerns address unauthorized access to memory or devices and robustness against misbehaving peripherals.

See also: device driver, memory-mapped I/O, direct memory access, PCI Express, USB, I/O virtualization.