Chip simulation of automotive ECUs

Modern ECUs contain ten thousands of engine parameters that need to be tuned. Calibration of all these parameters is time consuming and complex. Simulation on a PC could help to automate and speed up the calibration process, in particular if simulation runs much faster (e. g. 20 times) than real-time. However, engine calibration is typically performed by an OEM, while the ECU code is owned by the supplier of the ECU. Therefore, the OEM is typically unable to set up a ECU simulation based on the original C code of the ECU. Instead, to set up a simulation, time consuming and error prone reverse engineering is needed to develop an 'equivalent model' of the ECU function of interest. To improve this situation, we have integrated a chip simulator into the virtual ECU tool Silver. This is used to simulate hex files compiled for TriCore targets directly on PC. Simulation requires 1. a hex file that contains program code and parameters of the simulated functions 2. start addresses of the functions to be simulated 3. an ASAP2/a2l file that defines the conversion rules for the involved inputs, outputs, and characteristics, as well as corresponding addresses The start addresses of functions can e. g. be extracted from a map file generated together with the hex file. Silver uses the a2l file to automatically convert scaled integer values to physical values and vice versa during simulation. A TriCore simulation can also be exported as SFunction (mexw32 file) for use in MATLAB/Simulink. On a standard PC, hex simulation runs with about 40 MIPS. If only simulating selected functions of an ECU, this is fast enough to run a simulation much faster than real-time. In this paper, we also report how such simulations are used today to support the development of gasoline engines at Daimler.