Byteflight is an automotive databus created by BMW and partners Motorola, Elmos Semiconductor and Infineon to address the need for a modernized safety-critical, fault tolerant means of electronic communication between automotive components. It is a message-oriented protocol. As a predecessor to FlexRay, byteflight uses a hybrid synchronous/asynchronous TDMA based means of data transfer to circumvent deficiencies associated with pure event-triggered databuses.
It was first introduced in 2001 on the BMW 7 Series (E65).
Eclipse 500 jet aeroplanes use Byteflight to connect the avionics displays. [1]
In Byteflight terminology, a data frame is called a telegraph.
A telegraph starts with a start sequence containing six dominant bits. This start sequence is followed by a one byte message identifier. This is followed by a length field indicating the length in bytes of the transmitted data. The telegraph ends with a 15 bit CRC value encoded in two bytes leaving the LSB unused. [2]
All bytes are framed by a recessive start bit at the beginning and a dominant stop bit at the end.
The Baudot code[boˈdo] is an early character encoding for telegraphy invented by Émile Baudot in the 1870s. It was the predecessor to the International Telegraph Alphabet No. 2 (ITA2), the most common teleprinter code in use until the advent of ASCII. Each character in the alphabet is represented by a series of five bits, sent over a communication channel such as a telegraph wire or a radio signal. The symbol rate measurement is known as baud, and is derived from the same name.
The Transmission Control Protocol (TCP) is one of the main protocols of the Internet protocol suite. It originated in the initial network implementation in which it complemented the Internet Protocol (IP). Therefore, the entire suite is commonly referred to as TCP/IP. TCP provides reliable, ordered, and error-checked delivery of a stream of octets (bytes) between applications running on hosts communicating via an IP network. Major internet applications such as the World Wide Web, email, remote administration, and file transfer rely on TCP, which is part of the Transport Layer of the TCP/IP suite. SSL/TLS often runs on top of TCP.
In computing, endianness is the order or sequence of bytes of a word of digital data in computer memory. Endianness is primarily expressed as big-endian (BE) or little-endian (LE). A big-endian system stores the most significant byte of a word at the smallest memory address and the least significant byte at the largest. A little-endian system, in contrast, stores the least-significant byte at the smallest address.
High-Level Data Link Control (HDLC) is a bit-oriented code-transparent synchronous data link layer protocol developed by the International Organization for Standardization (ISO). The standard for HDLC is ISO/IEC 13239:2002.
The data link layer, or layer 2, is the second layer of the seven-layer OSI model of computer networking. This layer is the protocol layer that transfers data between nodes on a network segment across the physical layer. The data link layer provides the functional and procedural means to transfer data between network entities and may also provide the means to detect and possibly correct errors that can occur in the physical layer.
A Controller Area Network is a robust vehicle bus standard designed to allow microcontrollers and devices to communicate with each other's applications without a host computer. It is a message-based protocol, designed originally for multiplex electrical wiring within automobiles to save on copper, but it can also be used in many other contexts. For each device, the data in a frame is transmitted sequentially but in such a way that if more than one device transmits at the same time, the highest priority device can continue while the others back off. Frames are received by all devices, including by the transmitting device.
Modbus is a data communications protocol originally published by Modicon in 1979 for use with its programmable logic controllers (PLCs). Modbus has become a de facto standard communication protocol and is now a commonly available means of connecting industrial electronic devices.
IEEE 802.11i-2004, or 802.11i for short, is an amendment to the original IEEE 802.11, implemented as Wi-Fi Protected Access II (WPA2). The draft standard was ratified on 24 June 2004. This standard specifies security mechanisms for wireless networks, replacing the short Authentication and privacy clause of the original standard with a detailed Security clause. In the process, the amendment deprecated broken Wired Equivalent Privacy (WEP), while it was later incorporated into the published IEEE 802.11-2007 standard.
LIN is a serial network protocol used for communication between components in vehicles. The need for a cheap serial network arose as the technologies and the facilities implemented in the car grew, while the CAN bus was too expensive to implement for every component in the car. European car manufacturers started using different serial communication technologies, which led to compatibility problems.
A frame check sequence (FCS) is an error-detecting code added to a frame in a communication protocol. Frames are used to send payload data from a source to a destination.
FlexRay is an automotive network communications protocol developed by the FlexRay Consortium to govern on-board automotive computing. It is designed to be faster and more reliable than CAN and TTP, but it is also more expensive. The FlexRay consortium disbanded in 2009, but the FlexRay standard is now a set of ISO standards, ISO 17458-1 to 17458-5.
Token Ring is a computer networking technology used to build local area networks. It was introduced by IBM in 1984, and standardized in 1989 as IEEE 802.5.
DeviceNet is a network protocol used in the automation industry to interconnect control devices for data exchange. It utilizes the Common Industrial Protocol over a Controller Area Network media layer and defines an application layer to cover a range of device profiles. Typical applications include information exchange, safety devices, and large I/O control networks.
In computer networks, a syncword, sync character, sync sequence or preamble is used to synchronize a data transmission by indicating the end of header information and the start of data. The syncword is a known sequence of data used to identify the start of a frame, and is also called reference signal or midamble in wireless communications.
In computer networking, an Ethernet frame is a data link layer protocol data unit and uses the underlying Ethernet physical layer transport mechanisms. In other words, a data unit on an Ethernet link transports an Ethernet frame as its payload.
Action Message Format (AMF) is a binary format used to serialize object graphs such as ActionScript objects and XML, or send messages between an Adobe Flash client and a remote service, usually a Flash Media Server or third party alternatives. The Actionscript 3 language provides classes for encoding and decoding from the AMF format.
TTP/A is a time-triggered real-time fieldbus protocol used for the interconnection of low-cost smart transducer nodes. In contrast to the Time-Triggered Protocol (TTP), which is a high-speed, fault-tolerant communication network intended for safety critical applications, TTP/A provides a low-speed, low-cost protocol suitable for non-critical applications like car body electronics.
ISO 15765-2, or ISO-TP , is an international standard for sending data packets over a CAN-Bus. The protocol allows for the transport of messages that exceed the eight byte maximum payload of CAN frames. ISO-TP segments longer messages into multiple frames, adding metadata that allows the interpretation of individual frames and reassembly into a complete message packet by the recipient. It can carry up to 4095 bytes of payload per message packet.
Time-Sensitive Networking (TSN) is a set of standards under development by the Time-Sensitive Networking task group of the IEEE 802.1 working group. The TSN task group was formed in November 2012 by renaming the existing Audio Video Bridging Task Group and continuing its work. The name changed as a result of the extension of the working area of the standardization group. The standards define mechanisms for the time-sensitive transmission of data over deterministic Ethernet networks.
CAN FD is a data-communication protocol typically used for broadcasting sensor data and control information on 2 wire interconnections between different parts of electronic instrumentation and control system. This protocol is used in modern high performance vehicles. CAN FD is an extension to the original CAN bus protocol that was specified in ISO 11898-1. Developed in 2011 and released in 2012 by Bosch, CAN FD was developed to meet the need to increase the data transfer rate up to 5 times faster and with larger frame /message sizes for use in modern automotive Electronic Control Units (ECU)s. As in the classic CAN, CAN FD protocol is designed to reliably transmit and receive sensor data, control commands and to detect data errors between electronic sensor devices, controllers and microcontrollers. Although CAN FD was primarily designed for use in high performance vehicle ECUs, the pervasiveness of classic CAN in the different industries will lead into inclusion of this improved data-communication protocol in a variety of other applications as well, such as in electronic systems used in robotics, defense, industrial automation, underwater vehicles, medical equipment, avionics, down-hole drilling sensors, etc.