FETK – Fast ECU Interfaces

The combination of high transmission rate and small latency, as FETK ECU Interfaces offer it, is unique on the market. Because the investment in a FETK development ECU pays twice, for measurement and calibration as well as for prototyping experiments, the use of FETK ECU interfaces can make a major contribution to save development costs.

In contrast to validation and calibration of ECUs, where as much data as possible from the ECU has to be recorded simultaneously, prototyping of fast controls is depending on as small latency as possible. Functions are often model-based developed by means of ETAS ASCET or MATLAB®/Simulink® and then implemented on a special prototyping hardware, which communicates with the ECU in real-time. The latency of the communication when a 128 Byte long signal is exchanged between an FETK ECU interface and the prototyping hardware and back amounts less than 250 µs in the complete cycle. The flash memory of an ECU can be programmed via an FETK interface just as fast and save as with a debugger.

Different from the use of serial interfaces such as CAN, FETK interface operation by the ECU barely requires computing power. The independent power supply of an FETK enables to perform tests, as for example cold start tests independently of the operating state of the ECU.

The new FETK ECU Interface can be profitably and universally employed for diverse applications which demand different functionalities from the interface. From a user’s perspective, FETKs offer high ease of use: the Gigabit Ethernet interface is generic. This means it abstracts from the specific connection to the particular micro controller of an ECU. By means of an ES89x ECU and Bus Interface Module, applications can access ECUs with FETK interface via the standardized XCP-on-Ethernet protocol from their host device.

• High data transmission rates up to 20 MB/s (depending on the particular µC interface)
• XCP-on-Ethernet access to FETK-ECUs via an ES89x ECU and Bus Interface Module
• Best real-time behavior: Supports control cycles up to 10 µs
• Small latency of less than 250 µs in prototyping applications
• Simultaneous access of up to four applications to one ECU possible
• Compliant with ETK-S20.1 and ETK-S21.1

With FETK, ETAS has developed a new interface that connects the ECU and the host application through XCP via Gigabit Ethernet. FETKs are available in two versions: FETK-T and FETK-S. As regards handling, there is no difference between them: both are connected using the same type of cable to the interface module, with which they communicate using the efficient, latency-optimized FETK protocol. Via the ES89x module, applications can access the FETK ECU interface using XCP protocol, which facilitates easy integration with customer-specific solutions and third-party tools.

For measurement purposes, the FETK-T allows users to attain maximum data throughput. The measurement values can be captured from the ECU at a raw data rate of up to 300 Mbit/s via the AURORA Trace/ interface. This has almost no effects on the runtime behavior of the microcontroller in the ECU, because Trace data is generated independently of the ECU program through automatic copying of the values of the relevant measurement signals, which the µC cores write to RAM cells. In FETK-T the trace data, which consists of time stamps, memory addresses, values, and trigger events, are written to a mirror RAM. There they are selected from the various measurement grids with respect to trigger time and thereby reduced. Currently, during transmission of the reduced data, speeds already reach 20 MB/s over the entire route from FETK to the INCA V7.2 application on the host computer. Thanks to the µC trace mechanism’s high raw data rate, the FETK-T is also capable of recording signals from control system processes with repetition frequencies of up to 200 kHz with time precision. For prototyping and configuration purposes, both FETK-S and FETK-T use the microcontroller’s debug interface.

Through its µC connection via debug interface, FETK-S delivers a measurement performance that is perfectly sufficient for many calibration tasks. With a small 46 mm x 25 mm housing, this FETK model is ideal for installation in production ECU housings. This allows companies to reduce the costs of calibration projects.