Simulink Customize A2l

Customize A2L Files

Customize A2L (ASAP2) files generated from Simulink models using the coder.asap2 and coder.mapping APIs, avoiding silent errors and undocumented pitfalls.

When to Use

• Adding or modifying COMPU_METHODs (LINEAR, RAT_FUNC, TAB_VERB, IDENTICAL)
• Creating or modifying GROUPs in the A2L file
• Converting STD_AXIS to COM_AXIS for lookup tables
• Adding BIT_OPERATION (LEFT_SHIFT, RIGHT_SHIFT, SIGN_EXTEND) to measurements
• Creating VARIANT_CODING (VarCriterion, VarCharacteristic)
• Excluding inports, outports, or struct elements from the A2L
• Removing DEFAULT_EVENT_LIST or other IF_DATA blocks
• Any customization passed via CustomEcuDescriptions to coder.asap2.export

When NOT to Use

• Reading or parsing existing A2L files (use Vehicle Network Toolbox a2lfile)
• Configuring XCP/CAN transport layers
• Setting up Simulink model code generation (storage classes, data dictionaries)
• General Embedded Coder build workflows without A2L customization

Core Workflow

Decision: Direct export vs. customization workflow

• No element customization needed (only configuration like excluding struct elements or DEFAULT_EVENT_LIST): call coder.asap2.export directly with name-value options. No getEcuDescriptions needed.
• Element customization needed (adding/modifying/deleting measurements, characteristics, groups, etc.): use the full getEcuDescriptions → customize → export workflow.

% === Path A: Config-only (no element changes) ===
load_system(modelName);
slbuild(modelName);
coder.asap2.export(modelName, SupportStructureElements=false, IncludeDefaultEventList=false);

% === Path B: Element customization ===
load_system(modelName);
slbuild(modelName);

% 1. Create ECU descriptions — pass ALL configuration options here
descObj = coder.asap2.getEcuDescriptions(modelName, ...
    SupportStructureElements=false, ...
    IncludeDefaultEventList=false);

% 2. Customize elements
add(descObj, newElement);
set(descObj, 'ElementType', 'Name', Prop=value);
info = get(descObj, 'ElementType', 'Name');
names = find(descObj, 'ElementType');
delete(descObj, 'ElementType', 'Name');

% 3. Export — MUST pass descObj back or all customizations are silently lost
coder.asap2.export(modelName, CustomEcuDescriptions=descObj);

Critical: When using Path B, omitting CustomEcuDescriptions=descObj in the export call silently discards all customizations with no error.

Critical: When using Path B, construction-time options (SupportStructureElements, etc.) CANNOT be passed to export alongside CustomEcuDescriptions — they must be passed to getEcuDescriptions.

Key Functions

See references/object-properties.md for mandatory fields, valid types, and creation order for each coder.asap2.* class.

Pattern Routing

Match the user's task to the correct reference for detailed guidance:

Release Requirements

If the user's release is too old, inform them. Do not attempt workarounds — the APIs do not exist on older releases.

Common Mistakes

These cause silent failures or incorrect calibration data. Always check before generating code:

Conventions

• Verify A2L output with fileread after export — use contains for additions, ~contains for deletions/exclusions
• Use string arrays (not char vectors or cell arrays) for all multi-value properties
• Pass all configuration at getEcuDescriptions() construction time
• Use ForceShared=true for STD→COM_AXIS (never build AXIS_PTS manually for this)
• Use delete(descObj, 'ElementType', 'Name') to remove auto-created placeholders — this is the only recovery from the auto-creation trap caused by set() on a reference name before the referenced object exists
• Prefer coder.mapping.api over coder.asap2 when settings should persist with the model

Copyright 2026 The MathWorks, Inc.