[
  {
    "applicability": "Nominal operation after initialization with stable supported supply, shared supply/ground with the event source, and compatible captured pulse shapes. Requirements are inspection-derived, not physically verified. Events and control actions are separated from transition races unless stated otherwise; physical timing tolerances remain unresolved.",
    "case_ids": [
      "C-6dc6b750bdd040f39232493aa9329427",
      "C-5992aa7a91fa42bcbac47be824e632de",
      "C-a0b92339fe9a4469b1eb527f0a6de5ca"
    ],
    "rationale": "The operator must see an unambiguous ready condition and must explicitly choose when a measurement begins. Background Geiger pulses must not consume measurement positions before that choice; a pulse level must not be mistaken for multiple events.",
    "relationships": [],
    "revision": 1,
    "spec_id": "S-1a4ce041ee5b42768a726d2ca6a3e207",
    "statement": "After initialization completes, the device is idle with all progress and result indications off and no partial measurement awaiting completion. Signal pulses received in idle do not start acquisition and are not carried into a later acquisition. A fresh start press begins acquisition at zero accepted events. Holding the event signal low does not repeatedly generate events; returning it high alone does not register an event.",
    "title": "Initialization and idle event gating"
  },
  {
    "applicability": "Firmware-facing device boundary capability contract. Source-inspected behavior is not physically verified. Electrical and timing qualifications explicitly identified below remain unresolved.",
    "case_ids": [
      "C-5120f60bc4ac40a888134620875981e9",
      "C-e7d48736bc044cfca5e36126ab245190"
    ],
    "rationale": "The human-confirmed installation powers the device entirely through the GC. Requiring another power source or device control of source selection would change that installation. The same start, acquisition and indication functions must operate at both specified stable supply conditions. No internal conversion or GC charging implementation is prescribed.",
    "relationships": [],
    "revision": 2,
    "spec_id": "S-4b02b98f66e543b99d6cb5704b4bc521",
    "statement": "The device receives all operating power from the connected Geiger counter (GC). The GC independently selects whether it supplies battery voltage or 5 V. The device has no independent power source and does not control the GC source selection. The device shall support its start control, event acquisition, progress indications and result indication throughout a stable VCC supply range of 3.2 through 4.2 V inclusive, and at stable 5 V VCC. Ground is the supply and event-signal reference. These are battery-mode and plugged-in operating conditions respectively; no continuity guarantee during a supply-source transition is established by this requirement.",
    "title": "Supported supply conditions"
  },
  {
    "applicability": "Nominal operation after initialization at stable 3.2–4.2 V or 5 V supply. The Geiger source shares VCC and ground. Pulse capture and physical timing tolerances are not independently verified; compatible pulse shapes and readiness are assumed for these cases. Startup latency and minimum pulse width are unspecified. Characterization of a separately powered external source is outside the selected scope. Result eligibility follows the approved 25 ms interval-difference rule. Exact numeric presentation durations are not part of the selected compatibility contract; phase order and completion are required.",
    "case_ids": [
      "C-2200152c2acf475086cc418ec55a5135",
      "C-a4a554067d19475ca844294c539e0cd5"
    ],
    "rationale": "The two possible results must remain distinguishable using the reference color meanings. Fading and extinction communicate the end of result presentation. No particular light source or color-control protocol is required.",
    "relationships": [
      {
        "kind": "depends_on",
        "revision": 2,
        "spec_id": "S-84efd9a67eb7446d847b9e50e5c92913"
      }
    ],
    "revision": 3,
    "spec_id": "S-6f769f80d1fd4a2bb7034323d30eb781",
    "statement": "The device provides a visible result indication capable of red, green, decreasing brightness, and off. For an accepted measurement, a shorter first inter-event interval than second interval is indicated in red; a longer first interval is indicated in green. The result is initially steady, then fades, then turns off.",
    "title": "Visible red and green result capability"
  },
  {
    "applicability": "Firmware-facing device boundary capability contract. Source-inspected behavior is not physically verified. Electrical and timing qualifications explicitly identified below remain unresolved.",
    "case_ids": [
      "C-ce80b16075744ae29663ddffccbc5ace",
      "C-4c3583c4487d4cc58ff0c4e3493e0121",
      "C-69d4e4accd674d9bbe29a8d2a49e5f3b",
      "C-dfb4b7f5832a40fd81d73461ab1b5b0d",
      "C-0dcf5645301d424f90873e51445e1edc"
    ],
    "rationale": "These timing boundaries determine whether a given external event stream advances acquisition or yields a result. For example, moving the reference to every incoming pulse would reject the event 10 ms after an accepted event when an intervening pulse occurred at 6 ms; changing the near-equal boundary would change whether interval pairs of 1000/1025 ms produce a result. Preserving these outcomes requires temporal discrimination without prescribing an implementation. Exact numeric presentation timings have no established consumer dependency and are not required by this record.",
    "relationships": [],
    "revision": 2,
    "spec_id": "S-84efd9a67eb7446d847b9e50e5c92913",
    "statement": "During acquisition, an event less than 10 ms after the preceding accepted event is ignored; an event at exactly 10 ms is not excluded by this rule. Ignored incoming events do not extend this interval. A three-event measurement whose two successive intervals differ by less than 25 ms is retried without displaying a result; equality at 25 ms qualifies for a result. These are nominal event-time semantics. Physical timing accuracy and test tolerances remain unresolved; no particular clock, timer, interrupt or scheduling mechanism is required.",
    "title": "Temporal event discrimination capability"
  },
  {
    "applicability": "Firmware-facing device boundary capability contract. Source-inspected behavior is not physically verified. Electrical and timing qualifications explicitly identified below remain unresolved.",
    "case_ids": [
      "C-fa6eb07674dd4564b1f6121f9502b3de",
      "C-ee537f6d29ce4883b9e652a92a17deb7",
      "C-5ac2dc0d29b54836945e13119e8bbfa4"
    ],
    "rationale": "The operator must initiate successive measurements and must not lose an in-progress measurement through another press. This requires responsive idle operation and distinguishable press/release actions, not a specific switch wiring or processor sleep mechanism.",
    "relationships": [],
    "revision": 1,
    "spec_id": "S-a783aa9a8c1741bb894e1f995c1f61f8",
    "statement": "The device shall provide a momentary start control. A fresh press in idle begins acquisition without requiring a power cycle. Releasing the control does not begin another acquisition. A press during acquisition or result presentation does not restart, cancel or replace that activity. The control remains usable on return to idle.",
    "title": "Start control remains available in idle"
  },
  {
    "applicability": "Nominal operation after initialization at stable 3.2–4.2 V or 5 V supply. The Geiger source shares VCC and ground. Pulse capture and physical timing tolerances are not independently verified; compatible pulse shapes and readiness are assumed for these cases. Startup latency and minimum pulse width are unspecified. Characterization of a separately powered external source is outside the selected scope.",
    "case_ids": [
      "C-25a7264d1c684659ae64da6b9fe66951",
      "C-95aec3fd03b54c0eb17b216000360c0b",
      "C-07d5b13e4bdd4b5ca7cd4d6c9e368943"
    ],
    "rationale": "The human-confirmed GC installation provides exactly power, event signal and common reference. Preserving these three wire functions permits that connection without extra GC power or control conductors. Manual initiation and event polarity preserve measurement use. No connector geometry, pin layout or internal circuitry is prescribed.",
    "relationships": [
      {
        "kind": "depends_on",
        "revision": 2,
        "spec_id": "S-84efd9a67eb7446d847b9e50e5c92913"
      }
    ],
    "revision": 4,
    "spec_id": "S-c73b424891e04fdfb18a8e236db15bad",
    "statement": "The GC-to-device connection consists of exactly three wires: VCC supplies operating power from the GC to the device, SIGNAL carries event pulses from the GC into the device, and GND is the common power and signal reference. The three-wire count applies only to this connection, not to the device’s local controls or indications. The device provides a momentary manual start control. Actuating the control while idle starts event acquisition. During acquisition, a high-to-low signal transition is a candidate event subject to the event-acceptance timing rule; returning the signal high does not represent another event.",
    "title": "External event input and manual start"
  },
  {
    "applicability": "Nominal operation after initialization with stable supported supply, shared supply/ground with the event source, and compatible captured pulse shapes. Requirements are inspection-derived, not physically verified. Events and control actions are separated from transition races unless stated otherwise; physical timing tolerances remain unresolved.",
    "case_ids": [
      "C-6eb10bff6ed0477c80010d0cf7e94725",
      "C-8abb4c6519ee435f8d60ff4e3dd7f280",
      "C-3071774256cf43aeaf59f57c014e787e"
    ],
    "rationale": "The result represents the timing relationship of three source events, independently of operator reaction time. Retaining partial progress allows operation with sparse radiation events; using rejected pulses or start delay would change the reported result.",
    "relationships": [],
    "revision": 1,
    "spec_id": "S-c86a1940209349019276174eb47d9479",
    "statement": "An acquisition collects three accepted events in arrival order. Only accepted events advance progress or determine the two compared intervals. The first interval runs from accepted event one to two, and the second from two to three; the delay from start press to the first event does not affect the result. No acquisition timeout occurs solely because events stop arriving: the device waits with its accepted progress retained until sufficient events arrive. There is no manual cancellation or restart during acquisition.",
    "title": "Three-event acquisition and retained progress"
  },
  {
    "applicability": "Nominal operation after initialization at stable 3.2–4.2 V or 5 V supply. The Geiger source shares VCC and ground. Pulse capture and physical timing tolerances are not independently verified; compatible pulse shapes and readiness are assumed for these cases. Startup latency and minimum pulse width are unspecified. Characterization of a separately powered external source is outside the selected scope.",
    "case_ids": [
      "C-aaf251dbb073458b88ff1e9cdaa2069e",
      "C-e36609512d9b46be9d82c4401f8a878b"
    ],
    "rationale": "The operator needs to distinguish waiting for events from acquisition progress and completed acquisition. These visible roles do not require a particular LED package, layout or drive mechanism.",
    "relationships": [],
    "revision": 3,
    "spec_id": "S-c8e2fd5dae774aaaa4ef56da998e3d5d",
    "statement": "The device provides three distinguishable visual progress indications corresponding to the first, second and third accepted events. While acquiring, indications for events already accepted are steady on and those still pending blink. During a displayed result all three are on. In idle the progress indications are off.",
    "title": "Visible acquisition progress"
  },
  {
    "applicability": "Nominal operation after initialization with stable supported supply, shared supply/ground with the event source, and compatible captured pulse shapes. Requirements are inspection-derived, not physically verified. Events and control actions are separated from transition races unless stated otherwise; physical timing tolerances remain unresolved.",
    "case_ids": [
      "C-039dfee218784d03bb34e75ad39cb794",
      "C-4730e4432905402aa9a8bd0e44e6ff6e",
      "C-5ea95c5a1bad4333a5fc72a8555350ca"
    ],
    "rationale": "Near-equal measurements cannot select a usable result and must not leave the operator waiting for a hidden restart action. A fresh sample must consist of new events; reusing old events or forgetting the rejection interval would change the result stream.",
    "relationships": [],
    "revision": 1,
    "spec_id": "S-d4e5c1fe15e04541af2f77f660d2d780",
    "statement": "When the two intervals of a completed three-event acquisition differ by less than 25 ms, the device presents no colored result and automatically waits for three new accepted events without another start press. Progress returns to all-pending after the transition settles. None of the previous three events is reused in the new measurement. The 10 ms exclusion measured from the most recent accepted event continues across this retry transition.",
    "title": "Automatic fresh acquisition after near-equal intervals"
  },
  {
    "applicability": "Nominal operation after initialization at stable 3.2–4.2 V or 5 V supply. The Geiger source shares VCC and ground. Pulse capture and physical timing tolerances are not independently verified; compatible pulse shapes and readiness are assumed for these cases. Startup latency and minimum pulse width are unspecified. Characterization of a separately powered external source is outside the selected scope.",
    "case_ids": [
      "C-3b2721cf4e4a474fb98c3f3354509bc9",
      "C-3104128283ca47a4ae0f1552ecd54d05"
    ],
    "rationale": "The human-confirmed GC drives both voltage levels and requires the receiving device to observe without output drive or bias. This preserves the selected GC-to-device signal arrangement and does not mandate particular receiving hardware. The prior undriven-high guarantee is intentionally removed because it conflicts with the selected no-pull interface and has no continuing requirement.",
    "relationships": [],
    "revision": 3,
    "spec_id": "S-e232a0ffa2a4435da60c930a2c4ebf88",
    "statement": "The GC actively drives SIGNAL high to device VCC and low to common ground. The device shall observe SIGNAL solely as an input, without driving it and without pull-up or pull-down bias, including enabled internal GPIO pulls. The input shall accept compatible GC pulses at each supported supply condition (3.2–4.2 V and 5 V). A high-to-low transition is a candidate event subject to event-acceptance timing; a return high is not a second event. No defined voltage level or event behavior is required when SIGNAL is disconnected or undriven. Minimum pulse width, edge-rate limits and numeric input impedance/leakage limits remain unspecified. The GC shares device VCC and ground; separately powered-source compatibility is not required.",
    "title": "GC-driven event input without device drive or pulls"
  },
  {
    "applicability": "Nominal operation after initialization with stable supported supply, shared supply/ground with the event source, and compatible captured pulse shapes. Requirements are inspection-derived, not physically verified. Events and control actions are separated from transition races unless stated otherwise; physical timing tolerances remain unresolved.",
    "case_ids": [
      "C-9ec8f28ee15949979096ac69df77d7be",
      "C-0cd309645d164a04abd7726975ab3bba",
      "C-a25528c1a89e4ac69ce1beabea089ceb"
    ],
    "rationale": "The operator must be able to read one stable result and explicitly initiate the next measurement. Background source events and an earlier button action must not silently trigger another result or contaminate a fresh sample.",
    "relationships": [],
    "revision": 1,
    "spec_id": "S-ed1d964b8f454982af0cd8479cb5a4b3",
    "statement": "A qualifying third accepted event initiates one result presentation. The result stays in its selected red or green color through its steady and fading phases, with all three progress indications on. Signal pulses during presentation are discarded and do not alter its result or seed a later acquisition. Presentation completes automatically with result and progress indications off in idle. A new measurement requires a fresh start press in idle; a control held pressed from an earlier press during presentation does not automatically start one on completion.",
    "title": "Result completion and explicit rearming"
  }
]