PR#43 (L): Implemented scaling logic

CMakeLists.txt

@@ -47,6 +47,8 @@ set(SOURCES_LIST
     capture/src/raw_packet_queue.cpp
     capture/src/waveform_parser.cpp
     capture/src/waveform_ring_buffer.cpp
+    core/src/waveform_scaling.cpp
+    core/src/instrument_scaling_profile.cpp
     ${imgui_SOURCE_DIR}/imgui.cpp
     ${imgui_SOURCE_DIR}/imgui_draw.cpp
     ${imgui_SOURCE_DIR}/imgui_tables.cpp
@@ -62,6 +64,9 @@ set(HEADERS_LIST
     capture/inc/raw_packet_queue.h
     capture/inc/waveform_parser.h
     capture/inc/waveform_ring_buffer.h
+    core/inc/waveform_scaling.h
+    core/inc/instrument_model.h
+    core/inc/instrument_scaling_profile.h
 )
 
 set(RAW_PACKET_QUEUE_TEST_SOURCES_LIST
@@ -76,6 +81,14 @@ set(WAVEFORM_RING_BUFFER_TEST_SOURCES_LIST
     tests/waveform_ring_buffer_test.cpp
 )
 
+set(WAVEFORM_SCALING_TEST_SOURCES_LIST
+    tests/waveform_scaling_test.cpp
+)
+
+set(INSTRUMENT_SCALING_PROFILE_TEST_SOURCES_LIST
+    tests/instrument_scaling_profile_test.cpp
+)
+
 if(CMAKE_BUILD_TYPE MATCHES "Debug")
     message(STATUS ">>> Debug build")
     add_compile_definitions(_DEBUG)
@@ -103,6 +116,7 @@ target_include_directories(${APP_NAME} PRIVATE
     ${CMAKE_CURRENT_SOURCE_DIR}
     ${CMAKE_CURRENT_SOURCE_DIR}/usb/inc
     ${CMAKE_CURRENT_SOURCE_DIR}/capture/inc
+    ${CMAKE_CURRENT_SOURCE_DIR}/core/inc
     ${imgui_SOURCE_DIR}
     ${imgui_SOURCE_DIR}/backends
 )
@@ -153,6 +167,29 @@ if(BUILD_TESTING)
     enable_project_warnings(waveform_ring_buffer_tests)
     add_test(NAME waveform_ring_buffer COMMAND waveform_ring_buffer_tests)
     add_dependencies(${APP_NAME} waveform_ring_buffer_tests)
+    add_executable(waveform_scaling_tests
+        ${WAVEFORM_SCALING_TEST_SOURCES_LIST}
+        core/src/waveform_scaling.cpp
+    )
+    target_include_directories(waveform_scaling_tests PRIVATE
+        ${CMAKE_CURRENT_SOURCE_DIR}/core/inc
+    )
+    enable_project_warnings(waveform_scaling_tests)
+    add_test(NAME waveform_scaling COMMAND waveform_scaling_tests)
+    add_dependencies(${APP_NAME} waveform_scaling_tests)
+    add_executable(instrument_scaling_profile_tests
+        ${INSTRUMENT_SCALING_PROFILE_TEST_SOURCES_LIST}
+        core/src/instrument_scaling_profile.cpp
+    )
+    target_include_directories(instrument_scaling_profile_tests PRIVATE
+        ${CMAKE_CURRENT_SOURCE_DIR}/core/inc
+    )
+    enable_project_warnings(instrument_scaling_profile_tests)
+    add_test(
+        NAME instrument_scaling_profile
+        COMMAND instrument_scaling_profile_tests
+    )
+    add_dependencies(${APP_NAME} instrument_scaling_profile_tests)
     add_test(
         NAME release_updater
         COMMAND ${Python3_EXECUTABLE}

HISTORY.md

@@ -365,3 +365,65 @@ Records key decisions, structural changes, and completed development stages.
 - Verified application shutdown during acquisition: no hang or crash; the
   status LED blinked red briefly, then turned off.
 
+### Stage 4 - Scaling logic
+
+- Added a new `core` module with deterministic, hardware-independent
+  functions that convert raw two-channel capture samples into volts and
+  elapsed capture time.
+- Centered voltage scaling on the ADC midpoint (raw sample 128) with 32 raw
+  counts per vertical grid division, matching the legacy `glbox`/
+  `hantekdsoathread` display convention (8 vertical divisions across the
+  256-value 8-bit sample range).
+- Modeled elapsed sample time as a fraction of the full capture spanning the
+  10 horizontal grid divisions at the selected timebase.
+- Added shared voltage-scale and timebase lookup tables as the single source
+  of truth for both the scaling math and the existing UI combo-box labels,
+  with compile-time checks that the tables and labels stay in sync.
+- Wired the status line to show the scaled CH1/CH2 voltage and elapsed time
+  at the decoded trigger sample, proving the scaling pipeline end to end
+  without yet plotting the waveform shape, which remains a separate future
+  task.
+- Added deterministic CTest coverage for characteristic and boundary raw
+  sample values and sample-time fractions, including a zero-sample-count
+  guard.
+- Verified warning-free Debug and Release builds and a full CTest pass.
+
+### Stage 4 - Per-instrument scaling profile
+
+- Introduced `EInstrumentModel` and `SInstrumentScalingProfile` so timebase
+  steps, voltage-scale steps, grid divisions, and the ADC zero-volt center
+  value are looked up per connected instrument instead of one fixed table.
+- Replaced the single shared voltage/timebase lookup tables and their
+  compile-time label checks with `findInstrtScalingProfile()`, resolved once
+  per frame from the connected or last-scanned device identity, falling back
+  to the DSO-2250 profile so the UI always has scale steps to display.
+- Added deterministic CTest coverage for profile lookup, including the
+  fallback and an unknown-model case.
+
+### Known issue - live capture on real DSO-2250 hardware reports no waveform
+
+- Symptom: `GetCaptureState` polling never leaves the empty-buffer state on a
+  physical Hantek DSO-2250 (state byte stays `0x00`), so no channel data is
+  ever read and the display keeps showing no waveform, while Demo mode and
+  every deterministic CTest continue to pass.
+- Investigated and ruled out across several verified, warning-free
+  Debug/Release builds, each checked against fresh USB captures from the
+  physical device: a missing `ForceTrigger` before polling, an incomplete
+  `configureCapture()` command sequence, missing empty-response retry
+  handling, resending `TriggerEnabled` on every poll, and a missing
+  `SetOffset` (`CONTROL_SETOFFSET`, request `0xB4`) channel/trigger offset
+  command derived from the device's calibration table - all implemented,
+  hardware-tested, and individually confirmed insufficient.
+- Found by correlating each USB command byte with its immediately following
+  response byte across a full Windows reference driver capture (naive
+  per-endpoint response counts are misleading, because `GetCaptureState`,
+  `GetChannelData`, and the unrelated logic-channel/auto-range subsystem all
+  share bulk-IN endpoint `0x86`): the reference driver's completed-capture
+  state value is `3`, not the previously assumed `2`. Corrected
+  `captureCompleteState` from `2U` to `3U` for both DSO-2250 profiles in
+  `usb/src/usb_device.cpp`.
+- This correction is warning-free in Debug/Release and passes all CTest
+  cases, but still did NOT resolve the symptom on hardware retest - the
+  root cause remains open. Treated as a known, unresolved bug pending
+  further hardware-side USB capture analysis.
+

README.md

@@ -22,9 +22,11 @@ hardware-independent parser functions. Each supported-device entry supplies its
 capture protocol, including endpoints, packet size, commands, channel layout,
 sample count, and completion state. After a completed capture, the acquisition
 worker reads and queues the complete profile-defined sample buffer, then starts
-the next capture. Live waveform rendering is not yet implemented. A processing
-worker decodes complete captures and publishes the latest frame and trigger
-point safely for rendering.
+the next capture. A processing worker decodes complete captures and publishes
+the latest frame and trigger point safely for rendering. Deterministic
+functions convert raw capture samples into volts and elapsed capture time from
+the selected voltage-scale and timebase settings. Live waveform rendering is
+not yet implemented.
 
 ## Planned Stack
 
@@ -43,7 +45,9 @@ Oscilloscope/
 ├── capture/        Sample acquisition and processing.
 │   ├── inc/        Capture module headers.
 │   └── src/        Capture module implementations.
-├── core/           Shared types and application logic.
+├── core/           Voltage/timebase scaling and shared application types.
+│   ├── inc/        Core module headers.
+│   └── src/        Core module implementations.
 ├── docs/           Project documentation.
 ├── firmware/       Default path for local device firmware files.
 ├── render/         Oscilloscope waveform rendering.
@@ -211,10 +215,20 @@ and restores the previous files if the build fails.
 CI can update only the version metadata by passing `--skip-build`.
 
 
+## Known Issues
+
+- Live capture on a physical Hantek DSO-2250 never reports a waveform:
+  `GetCaptureState` polling stays at the empty-buffer state, so no channel
+  data is read. Demo mode and the full CTest suite are unaffected. See
+  `HISTORY.md` ("Known issue - live capture on real DSO-2250 hardware
+  reports no waveform") for the investigation and ruled-out causes.
+
 ## Next Steps
 
-1. Render live and demo waveforms on the display grid.
-2. Implement the two-channel model, timebase, and instrument controls.
+1. Diagnose the live-capture-never-completes issue on real DSO-2250
+   hardware.
+2. Render live and demo waveforms on the display grid.
+3. Implement the two-channel model, timebase, and instrument controls.
 
 The full goals, constraints, and architecture are documented in
 `WorkingDocs/TECHNICAL_SPECIFICATION.md`.