Building block view

arc42 §5 — the building blocks that realise EtherCAT network-config cod... (FEAT_0080), showing the codegen data flow from network.yaml through the parse and codegen layers to the generated &'static tables consumed at runtime.

Structural overview

The toolchain is four layers that depend only leftwards. An integrator authors network.yaml; the build-script glue (ethercat-netcfg SM-watchdog... (BB_0096) is the SM-watchdog slice) drives the parse and codegen layers into OUT_DIR; the consumer crate pulls in the emitted module via include!.

        graph LR
    yaml["network.yaml<br/>(integrator-authored)"]
    esi["ESI files<br/>(vendored, pinned)"]
    parser["ethercat-netcfg<br/>(parse layer)<br/>depends on ethercat-esi<br/>+ fieldbus-od-core"]
    ir["NetworkConfig IR<br/>(typed, in-memory)"]
    codegen["ethercat-netcfg-codegen<br/>(codegen layer)<br/>IR → TokenStream<br/>prettyplease formatting"]
    build["ethercat-netcfg-build<br/>(build-script glue)<br/>invoked from build.rs<br/>writes to OUT_DIR"]
    cli["ethercat-netcfg-cli<br/>(netcfg expand / fetch)<br/>vendor-and-pin action"]
    out["OUT_DIR/network.rs<br/>pub static PDO_MAP<br/>EthercatRouting consts<br/>bring-up assertions"]
    consumer["consumer crate<br/>include!(…/network.rs)"]

    yaml --> parser
    esi --> parser
    parser --> ir
    ir --> codegen
    codegen --> build
    build --> out
    out --> consumer
    yaml -.->|"netcfg fetch"| cli
    cli -.->|"vendors + pins"| esi

5. Building blocks

The SM-watchdog resolution and validation building block is the only arc42 building block named in this v1 slice; the broader parse / codegen pipeline is described by the capability-cluster features (Network-config parser and IR (FEAT_0081) – Validation and bring-up ass... (FEAT_0085)) and their decisions.

Building Block: ethercat-netcfg SM-watchdog resolution and validation BB_0096
status: open
refines: REQ_0844, REQ_0845
implements: FEAT_0085
links incoming: REQ_0844, REQ_0845

The parse-layer code that, at resolve() time, resolves and validates each output device’s sync-manager watchdog (the netcfg slice of Output-slave watchdog enabl... (AOU_0016)). For every device carrying output (rx) PDOs it computes an effective timeout — the per-device sm_watchdog_timeout override if present, else FTTI/2 — quantizes it to the ESC registers 0x0400 / 0x0420 (divider 2498 → 100 µs ticks, intervals = ceil(timeout_us / 100), clamped 1..=u16::MAX), and exposes the resolved (divider, intervals) on the IR for codegen. The quantization arithmetic is a deliberate ~5-line duplicate of the connector’s SmWatchdog (a dependency on the connector runtime was rejected per Parser depends on ethercat-... (REQ_0824)). Validation rejects an effective window that exceeds FTTI/2 (checked against the QUANTIZED value, since ceil can push a boundary request over the bound), an ESI-sourced output SM whose watchdog trigger is disabled, and an inline-sourced output device that does not attest sm_watchdog_enabled: true. Input-only devices are untouched. Implemented in crates/taktora-ethercat-netcfg/src/lib.rs and crates/taktora-ethercat-netcfg-codegen/src/lib.rs.