In-depth analysis of AutoSAR series: Dem

In-depth analysis of AutoSAR series: Dem

I. Introduction

In the automotive field, the Diagnostic Event Manager (Dem for short) is a powerful software module responsible for managing and diagnosing fault events in vehicles. This article will introduce the functional principle and application of Dem in detail, and provide corresponding source code examples.

2. Overview of Dem

The Dem module is part of the AutoSAR (AUTomotive Open System ARchitecture) standard, designed to implement vehicle diagnostics and fault management functions. The Dem module works closely with other AutoSAR modules such as Dcm (Diagnostic Communication Manager) and PduR (Protocol Data Unit Router) to build a complete vehicle diagnostic system.

The Dem module mainly has the following functions:

1. Fault event management: Dem is responsible for monitoring the status of each subsystem of the vehicle, and classifying and storing detected fault events. When a fault event occurs, Dem will generate a corresponding DTC (Diagnostic Trouble Code) and report it to the upper diagnostic communication module.
2. Event storage: Dem stores fault events in the form of event snapshots, including event occurrence time, priority, status and other information. This information is very valuable for failure analysis and repair.
3. Event processing and priority management: Dem processes and responds to different fault events according to pre-defined priority rules. High-priority fault events will be reported to the upper system immediately, while low-priority events can be flexibly determined through configuration whether to report or not.
4. Freeze frame generation: Dem supports the generation of required freeze frame (Freeze Frame) data and provides it to the upper diagnostic communication module. Freeze frame is a snapshot of the vehicle state at the time of the fault, which is helpful for fault analysis and problem location.

3. Workflow of Dem

Let's go into details