S32CT Generate .mex Configuration

Bootstrap helper that produces a well-formed S32 Configuration Tools .mex project file by cloning a bundled <MCU>_default.mex template and applying a structured JSON delta (tool enable/disable, peripheral add/remove/patch, pin and clock overrides). The output can be opened in S32CT, fed to the s32ct-* CLI skills, or handed to s32ct-generate-code to emit driver sources.

When to use

• Use for: producing a starter .mex for an S32 MCU with specific peripherals enabled/disabled or specific parameter overrides, without hand-editing 100+ KB of XML; scaffolding a deterministic .mex for CI / test flows from a small JSON patch; emitting an input artefact for downstream s32ct-* skills.
• Do not use this skill for: interactively editing pin routing or clock trees (use s32ct-pins-facade / s32ct-clocks-facade or the GUI); generating C driver code from a .mex (use s32ct-generate-code); discovering what a peripheral exposes (s32ct-peripherals-info).

Available Capabilities

Capability	Notes
Plain clone with fresh UUID	Default when no modifications supplied. Sidecar ClockConfigurationMappings.txt propagated.
Tool enable/disable	Toggles top-level <pins>, <clocks>, <peripherals>, <dcd>, <ivt>, <efuse>, <gtm>, <quadspi>, <ffc>, <serdes> sections.
peripherals.add / .remove / .patch	Insert new <instance> blocks, drop by name, or override <set id="...">value</set> fields.
Pin and clock patches	Structured deltas into the Pins and Clocks tool sections.
Optional headless validation	validate=true runs toolsc.exe -HeadlessTool <tool> -ShowProblems and folds captured stderr into the report.
MCU-agnostic template resolution	Any <MCU>_default.mex dropped into the skill folder becomes available automatically. See references/adding-new-mcu.md.

Quickstart

1. Identify the target MCU. If a <MCU>_default.mex is not yet bundled for that MCU, follow references/adding-new-mcu.md first.
2. Assemble inputs: output_path (required), optional mcu, package, mcu_data, modifications (see references/patching-recipes.md), and flags regenerate_uuid (default true), copy_sidecars (default true), overwrite (default false), validate (default false).
3. Invoke the skill. Behaviour:
   1. Resolve template: template_path if supplied, else <skill_dir>/<mcu>_default.mex. Reject with a template-missing error and list the bundled *_default.mex files if not found.
   2. Load template as XML, preserving namespace and attribute order.
   3. Apply modifications in the order: common, tools, peripherals.remove, peripherals.add, peripherals.patch, pins, clocks.
   4. If regenerate_uuid=true, assign a fresh top-level UUID v4.
   5. Serialise to output_path (refuse if it exists and overwrite is false). Preserve encoding and line endings.
   6. If copy_sidecars=true, copy ClockConfigurationMappings.txt (and any other sibling sidecar) alongside.
   7. If validate=true, run headless validation - see below.
4. Return a Markdown report: generated file path, summary of what changed vs. template, validation result (if run), and next-step suggestions.

Example - plain clone (default MCU):

{ "output_path": "C:\\tmp\\S32K312_starter.mex" }

Example - enable boot-image tools:

{
  "output_path": "C:\\tmp\\S32K312_boot.mex",
  "overwrite": true,
  "modifications": {
    "tools": { "DCD": { "enabled": true }, "IVT": { "enabled": true } }
  }
}

More recipes in references/patching-recipes.md.

Configuration

• Bundled template: S32K312_default.mex (S32K312 / S32K312_172HDQFP / PlatformSDK_S32K3, schema mex_configuration_19, core M7_0).
• Bundled sidecar: ClockConfigurationMappings.txt carrying the ,PB,ClockConfig0 mapping line.
• Launcher for optional validation: toolsc.exe (desktop distribution) or s32dsc.exe (integrated_s32ds distribution), auto-discovered by the MCP at startup. See s32ct-distributions.

Guardrails

• Scope. Read the bundled <MCU>_default.mex templates, write only to the user-supplied output_path (and sibling sidecar). Never modify a template in place - patch a copy. No target hardware, no FreeMASTER, no registers touched.
• Destructive actions. Refuse to overwrite an existing output_path unless overwrite=true is explicitly set. Refuse to patch on unknown top-level modification keys or unknown type_id values rather than silently ignoring.
• Refuse and escalate. If the requested MCU has no matching <MCU>_default.mex, reject the request, list the bundled templates, and point the user at references/adding-new-mcu.md. If a supplied package / mcu_data disagrees with the template's <part_number> / <mcu_data>, reject with a comparison message rather than rewriting the template.

Validation loop

1. Copy output_path to a no-space location (e.g. C:\tmp_mex\); cmd's stderr redirection fails on paths containing spaces.
2. Run toolsc.exe -Load <path> -HeadlessTool <Tool> -ShowProblems once per tool (Pins, Clocks, Peripherals, DCD, IVT, eFUSE, GTM, QuadSPI, FFC are the accepted values).
3. Capture stdout and stderr - the Problems View prints to the originator terminal only; no log file is created by default. Redirect to file for durability (> problems.txt 2>&1).
4. Ignore the exit code. toolsc.exe exits 0 even when the Problems View contains errors. Parse the captured text.
5. Zero problem lines after noise filtering means the tool is clean. Any remaining SEVERE: [TOOL] or SEVERE: [Generation lines are real - fix and re-run.

The skill folds this loop into the report when validate=true. The canonical filter-then-count noise patterns are documented in s32ct-peripherals-author-mex/references/error-decision-tree.md (section: framework-noise catalog).

Out of scope

• Interactive pin muxing or clock tree exploration.
• Enumerating the RTD peripheral catalogue (that is s32ct-peripherals-info).
• Generating driver C sources (that is s32ct-generate-code).
• Applying -ApplyUseCase / -ImportC / -SetValue transformations (that is s32ct-cli or a per-tool facade).
• Rewriting the schema namespace, <part_number>, or <mcu_data> fields of a template.

See Also

• references/mex-schema.md - XML schema, namespace preservation, per-tag semantics.
• references/patching-recipes.md - JSON patch shapes, application order, per-driver examples, error responses.
• references/adding-new-mcu.md - procedure for dropping a new <MCU>_default.mex template.
• s32ct-distributions - launcher / prefix selection for the two S32CT distributions.
• s32ct-peripherals-info - resolve type_id values for peripherals.add.
• s32ct-peripherals-author-mex, s32ct-peripherals-graft-mex - author or lift-and-adapt driver <instance> blocks.
• s32ct-pins-author-mex, s32ct-pins-info - author or inspect pin routing.
• s32ct-generate-code - emit driver C sources from the produced .mex.
• s32ct-cli, per-tool facades (s32ct-peripherals-facade, s32ct-clocks-facade, ...) - headless transformations after generation.