Byteflight

Byteflight is a new high performance data bus system

It was already presented in the chapter on the CAN bus. The CAN protocol only transmits data if a transmission request, that is an event, exists. Therefore the data transmission method of the CAN can also be characterised as "event controlled" or "asynchronous", somewhat in contrast to a purely time controlled data transmission method. With this method every bus device transmission time is made available in a definite raster (synchronous method). Purely time controlled data transmission methods have only a very limited importance in motor vehicles; therefore they are not covered in this learning sequence.

Since all messages from all bus devices are made available simultaneously with CAN, access by the bus device to the bus is controlled by priority or by chance. But then "rest times " or " latency times" remain which can only be determined statistically. This is not sufficient for very high demands such as safety-critical systems.

Therefore BMW developed a new high performance data bus system with the name 'byteflight' for the new 700 series, in teamwork with Motorola, Elmos and Infineon. It is used primarily for the transmission of especially time critical data with very high data rates in the airbag system, but also in the electronics of the body and chassis. It must function without transmission error even in a very difficult electromagnetic environment.