devicetohost

Devicetohost is a term used to describe the direction of data flow from a peripheral device to the host system. It is commonly encountered in discussions of hardware interfaces, device drivers, and data transfer protocols, where it is often contrasted with hosttoDevice, which denotes data moving from the host to a device.

In USB terminology, device-to-host transfers occur on IN endpoints. From the host’s perspective, data travels from the device to the host, even though the host initiates transactions. This directionality helps drivers manage buffers, interrupts, and data processing paths for incoming data such as sensor readings, file transfers, or event streams.

Beyond USB, devicetohost is a broad concept used in other architectures that support direct device-to-host data movement, including DMA-capable bus systems and memory-mapped I/O. In these contexts, the term describes data produced by a device and transferred into host memory for processing by the host CPU, rather than data produced by the host being sent to a device.

Software and hardware implementations commonly encode direction as a flag or enum, allowing code paths to handle device-to-host transfers differently from host-to-device transfers. This helps optimize buffering, error handling, and timing constraints, and clarifies responsibilities between devices and host software.

See also: hosttoDevice, USB, DMA, PCIe, endpoint, data transfer direction.