A Low-Cost Time-Triggered Sensor Network: TTP/A

This paper presents the rational and the design of a time-triggered low-cost sensor network that conforms to the design principles of the timetriggered architecture. TTP/A is a multimaster UART-based sensor network that provides temporally predictable communication to sensor and actuator nodes in a distributed real-time system. It provides multiple views of a sensor node, such as a periodic real-time service view and an aperiodic diagnostic view. Since the protocol provides start-up synchronization of the sensor nodes by the master, the functionality of the sensor node can be implemented on any low-cost microcontroller with an imprecise on-chip resonator, a timer, and a digital input/output port. The UART functionality can be implemented in software. The construction of fault-tolerant sensor networks using TTP/A is shown. An implementation of the TTP/A protocol is presented.