ECU Objects

Overview

The ECU contains a number of “objects” that represent settings or measurements and have varying types (e.g. Tables or Maps).

An object in this sense just refers to any ’thing’ in the ECU that can be configured or viewed in GWv4.

Alternatively, an “ECU Object” could be viewed as a memory range in the ECU memory map, which may be a single bit, a byte, a word, or a larger array of items in memory.

Nomenclature

This table shows an approximate mapping between the terms used in GWv4 and the terms used in the XCP/A2L and Simulink® worlds.

Note that Options / Tables / Maps are allowed to be stored in non-calibration (i.e. volatile RAM) memory and the same goes for Simulink signals, which is why this mapping is only approximate.

Calibration vs Measurement Objects

Calibration objects are those that can be modified by the user and are stored permanently by the ECU in non-volatile memory. These values are usually read from the ECU once when connecting to it.

Measurement objects are generally read-only and used to display real-time feedback about the ECU’s operation. Measurements are read frequently from the ECU when visible in the user interface or if they are being used for PC logging. There are some exceptions to this for monitoring some specific ECU functions, such as whether or not there are changes to the calibration that have not been saved to non-volatile memory.

See Calibrations for more information on calibration files / non-volatile storage.

The ECU may be configured to log measurements in internal logging memory for later retrieval. This is useful for diagnosing problems that may not be visible in real-time and offers much more precise timing resolution than is possible when polling the ECU over a comms link.