Byteflight

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).

Data Frame

Data Frame is called telegraph in Byteflight specification. Data frame start with a start sequence containing six dominant bits the start sequence is followed by one byte message identifier followed by a length field which contain the size of the data sent in bytes. Byteflight specification currently supports only data length up to 12 bytes, the length field is followed by the data field which may be up to 12 bytes in size the datagram then ends with a 15 bit CRC encoded in two bytes with the LSB left unused. All the bytes are cushioned in the beginning by a recessive start bit and a dominant stop bit.

External links

• byteflight website