Busprotokolls

Busprotokolls describes the set of rules that govern data exchange over a shared communication medium in a bus system. A busprotokoll defines how devices format data frames, address participants, synchronize timing, arbitrate access to the bus, and detect or recover from errors. It aims to enable multiple devices to communicate reliably with bounded latency and without destructive collisions, even in noisy environments.

Bus architectures can be centralized or decentralized, and common topologies include single master with multiple slaves and multi-master networks. Arbitration methods vary: some protocols use fixed mastership, while others permit arbitration by message priority or time-slot assignment. Determinism and real-time performance are critical in automotive and industrial contexts, so many busprotokolls provide guarantees on latency or bandwidth.

Notable examples across domains include CAN (Controller Area Network), which uses a broadcast bus with arbitration by message identifier; I2C (Inter-Integrated Circuit), a two-wire protocol with master-driven communication and addressing; SPI (Serial Peripheral Interface), a simple high-speed master-slave protocol without arbitration; LIN (Local Interconnect Network), a cheaper automotive bus with a single master; and MODBUS, used in industrial automation over serial or TCP. More recent developments include Ethernet-based fieldbuses and real-time Ethernet variants such as EtherCAT and PROFINET, which offer higher bandwidth and standardized network layers while preserving application-specific bus semantics.

Busprotokolls are governed by standards bodies such as ISO, IEC, IEEE, SAE, and various industry consortia. Some busprotokolls are open standards, while others are vendor-specific or proprietary. They are distinct from higher-layer network protocols: they define the access method and basic data transfer within a shared medium, while application protocols atop them define commands, data formats, and semantics.