Battle of the busses

The automotive world is looking for a bus to catch. Audi thinks it has found the answer.

The automotive world is looking for a bus to catch. A bus that will allow future control systems in a car to communicate with one another. Audi thinks it has found the answer.

German auto manufacturer Audi has recently thrown its lot in with Austrian-based TTTech Computertechnik. It plans to use TTTech’s ‘Time-Triggered Architecture’ for distributed real-time embedded control in future generations of integrated vehicle control systems.

Computertechnik’s Time-Triggered Architecture architecture itself includes a fault-tolerant real-time communication system (TTP/C), a time-triggered field bus (TTP/A) and a time-triggered operating system (TTOS). It is based on a TDMA (Time Division Multiple Access) media access strategy, unlike competitive busses like CAN that use carrier sense multiple access with collision avoidance (CSMA/CD).

Semiconductor house Austria Mikro Systeme International are currently working with TTTech to develop a next generation TTP/C communication controller chip that should be available by the end of the second quarter this year. The chip will be a follow up to the AS8201 – the first device the companies worked on together.

This new version — the AS8202, will be a stand-alone device featuring a communication speed of up to 25 MBit per second, sport integrated flash memory, a 4kByte communication buffer as well as 8kByte of instruction RAM. Available in a TQFP80 package and with a single 3.3V supply voltage, the device will be qualified for extended automotive range.

Apart from CAN, TTTech’s obvious competitor in the automotive bus business, BMW, Motorola and Siemens have developed yet another new protocol, dubbed Byteflight. This one, however, is targeted at safety-critical applications.