AUTOSAR COM
The configuration map
Everything COM does is decided in advance, in its configuration. This lesson shows where each feature from the course lives in that configuration, and under which name.
COM has no code for your car
The COM software is the same in every control unit. What makes it yours is a big table of settings: which packets exist, which signals sit where, which are triggered, which timeouts apply. Nothing of this is decided while the car runs.
The settings are usually not typed by hand. The car maker describes the whole network in one file, and a tool derives each control unit's COM settings from it. Still, when something behaves oddly, these settings are where you look.
The shape of the configuration
Settings are sorted into boxes inside boxes, called containers. This is the part of the tree that matters for this course. The plain word from the lessons is on the right.
- ComConfig everything
- ComIPdu one packet
- ComTxIPdu extras for a sending packet
- ComTxModeTrue → ComTxMode send setting "true"
- ComTxModeFalse → ComTxMode send setting "false"
- ComTxIPdu extras for a sending packet
- ComSignal one signal
- ComFilter its filter, or its send-setting condition
- ComSignalGroup one signal group
- ComGroupSignal one member
- ComIPduGroup one packet group
- ComGwMapping one gateway copy rule
- ComGwSource copy from
- ComGwDestination copy to
- ComIPdu one packet
A packet does not contain its signals in this tree. It points to them, and each signal says at which bit of the packet it sits.
Find the settings for a feature
Pick a feature. You get the few settings that control it, where they are, and what they decide.
| Setting | In container | Decides |
|---|
How to read a setting name
The names look long but follow a pattern. They start with Com, then say what they belong to, then what they set. ComTxModeTimePeriod is: COM, send setting, timer period. ComRxDataTimeoutAction is: COM, received data, action on timeout. Read them from left to right and most explain themselves.
When you have to do it yourself
For real configuration work there are three helpers: a configurator that turns plain answers into settings and values, a recipe book for typical jobs, and a troubleshooting guide.
Check yourself
Optional. Answer from memory.
The AUTOSAR words
| Plain word here | AUTOSAR word |
|---|---|
| Box of settings | Container |
| Setting | Configuration parameter |
| The network description file | System description (an ARXML file) |
Source: AUTOSAR COM specification, R25-11, chapter 10 (configuration specification). Only the settings needed for this course are shown; the specification lists them all.