Distributed Systems Interface

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The Distributed Systems Interface ( DSI ) is a bus protocol .

General

The DSI is used to connect several distributed systems , sensors and actuators to a central control unit. The most important application for the bus protocol are airbag systems in vehicles. Some of the features for the application are the need for an inexpensive, robust, medium speed connection limited to two lines. In addition, it must be fail-safe, deterministic and have good EMC properties . Even if devices of all levels of complexity and programmability can establish a connection to the network, it must be possible to implement distributed systems with simple state machines . Since the module size is an important factor, a minimum of components both in the central control unit and in the distributed systems is critical.

Airbag systems have many types of components that need to be connected to the network. Typically, these components are supplied directly to the vehicle assembly facility by suppliers. Some can be embedded in instrument panels and steering columns, others in seats, others possibly in the wiring harness. The number of distributed devices is typically two-digit. For this reason it is desirable that the network addressing can be configured automatically when it is switched on. This minimizes the number of device types and eliminates the need for special programming devices for component suppliers and vehicle assembly.

The above topics were the inspiration for the development of the DSI. To maintain determinism without sacrificing bus bandwidth and simplicity, a single master / multiple-slave configuration is used. The robustness is achieved through the use of checksums (CRC) in the messages and distributed self-diagnosis. High message density at medium speeds and costs is facilitated by the simultaneous transmission of the power supply, master commands and slave responses. In a single ended configuration, one of the wires is ground. An optional daisy chain connection procedure is defined that enables the assignment of network addresses when switching on with a priori device information in the central module.

There are two variants of this bus protocol: Standard and Enhanced. Devices of both forms can be mixed on one bus and use standard DSI operation. The enhanced DSI bus operation requires that all devices on the bus are compatible with the enhanced DSI standard.

See also

literature

  • DSI3 Bus Standard Rev 1.00 (PDF) ( download )

Individual evidence

  1. ^ DSI Consortium. Retrieved July 27, 2017 .