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Configuration Notes for the Com Module

The AUTOSAR Com module manages signal-based communication: it packs signals into I-PDUs for transmission and unpacks received I-PDUs into signals. The configuration is consumed by Com.py, which imports message/signal definitions from a DBC (CAN) or LDF (LIN) database and generates GEN/Com_Cfg.c / GEN/Com_Cfg.h. The example in this document is app/app/config/Com/Com.json and the generated output is in app/app/config/Com/GEN.

1. CAN network example

{
  "class": "Com",
  "E2E": "../E2E/E2E.json",
  "networks": [
    {
      "name": "CAN0",
      "network": "CAN",
      "device": "simulator_v2",
      "port": 0,
      "baudrate": 500000,
      "me": "AS",
      "groups": [
        { "SystemTime": ["year", "month", "day", "hour", "minute", "second"] }
      ],
      "use_dbc": true,
      "dbc": "CAN0.dbc",
      "trigger": ["CanNmUserData"],
      "E2E": [ { "name": "TxMsgTime", "profile": "P11" } ]
    }
  ]
}

2. LIN network example

For LIN, ldf replaces dbc. The generator converts the LDF into an internal DBC representation first, so all downstream processing is identical:

{
  "class": "Com",
  "networks": [
    {
      "name": "LIN0",
      "network": "LIN",
      "me": "AS",
      "ldf": "LIN0.ldf"
    }
  ]
}

The network name must match the name used by LinIf so that signal routing and the LDF interpretation stay consistent (see the LinIf document).

3. Network fields

Field	CAN	LIN	Description
name	yes	yes	Network identifier, must match CanIf/LinIf
network	"CAN"	"LIN"	Physical network type
me	yes	yes	Local ECU node name inside the DBC/LDF
device	yes	no	CAN device name, for example simulator_v2
port	yes	no	Controller port index
baudrate	yes	no	CAN baud rate in bit/s
dbc / ldf	dbc	ldf	Database file with messages and signals
use_dbc	optional	-	When true, all messages of node me in the DBC are imported
groups	optional	optional	Signal groups; each group maps one group name to its member signals
trigger	optional	-	Message names that use trigger-transmit (on LIN every message is trigger-transmitted)
messages	optional	optional	Hand-written message/signal definitions added to or overriding the database import (for example SecOC PDUs not present in the DBC)
E2E	optional	optional	Per-message E2E profile list, for example { "name": "TxMsgTime", "profile": "P11" }; emitted only when USE_E2E is defined
enable_message_tx_callout / enable_message_rx_callout	optional	optional	When true, generate a global user callout invoked for every transmitted/received message

4. Signals and groups

• Signals carry start, size, endian (big/little), sign, factor, offset, min, max and an optional node list; the generator emits the pack/unpack code and the signal initial values.
• A groups entry collects several signals into one AUTOSAR signal group that is received and read consistently as a unit (for example the SystemTime group).
• Messages listed in trigger are sent on demand through Com_TriggerIPDUSend() instead of a periodic timer.

5. Generator

Com.py reads the JSON and the database files, runs the optional LDF-to-DBC conversion for LIN networks, applies group, trigger, E2E and callout processing and emits GEN/Com.json plus Com_Cfg.c/Com_Cfg.h in the configuration directory.

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