Fix engineer screen state updates

Reviewed-on: #59

README.md

@@ -214,3 +214,10 @@
   - `loadFluenceTable()`, `loadHzTable()`, `calculateInterpolatedC()` 영향 확인
 - 성능/안정성 이슈 시
   - `txPacketLoop()` 주기, `RX_TIMEOUT_THRESHOLD`, DB 로그 적재량 점검
+
+## 10) Troubleshooting
+
+- 시리얼 초기 TX 누락(Startup race, FD 설명, 수정 내역):
+  - [`docs/serial_tx_startup_race.md`](docs/serial_tx_startup_race.md)
+- 변경 요약 문서(`git diff` 기준):
+  - [`docs/change_summary_2026-03-04.md`](docs/change_summary_2026-03-04.md)

app/src/main/java/com/laseroptek/raman/const/HzTable_10_10.kt

@@ -9,7 +9,7 @@ package com.laseroptek.raman.const
 
 val HzTable_10_10 = mapOf(
     // Pulse Width = 0.5f
-    Pair(0.5f, 0.5f) to KEY_BLUE,
+    Pair(0.5f, 0.5f) to KEY_GREEN,
     Pair(0.5f, 0.6f) to KEY_BLUE,
     Pair(0.5f, 0.7f) to KEY_BLUE,
     Pair(0.5f, 0.8f) to KEY_BLUE,

app/src/main/java/com/laseroptek/raman/const/HzTable_5_5.kt

@@ -24,7 +24,7 @@ val HzTable_5_5 = mapOf(
     Pair(0.5f,3.4f) to KEY_BLUE,
     Pair(0.5f,3.6f) to KEY_BLUE,
     Pair(0.5f,3.8f) to KEY_BLUE,
-    Pair(0.5f,4.0f) to KEY_YELLOW,
+    Pair(0.5f,4.0f) to KEY_BLUE,
     Pair(0.5f,4.2f) to KEY_YELLOW,
     Pair(0.5f,4.4f) to KEY_YELLOW,
     Pair(0.5f,4.6f) to KEY_YELLOW,

app/src/main/java/com/laseroptek/raman/const/HzTable_7_7.kt

@@ -108,7 +108,7 @@ val HzTable_7_7 = mapOf(
     Pair(1.5f, 8.0f) to KEY_GRAY,
 
     // Pulse Width = 3f
-    Pair(3f, 1.1f) to KEY_RED,
+    Pair(3f, 1.1f) to KEY_GRAY,
     Pair(3f, 1.2f) to KEY_GRAY,
     Pair(3f, 1.3f) to KEY_GRAY,
     Pair(3f, 1.4f) to KEY_GRAY,

app/src/main/java/com/laseroptek/raman/data/model/serial/HandPiece.kt

@@ -1,5 +1,5 @@
 package com.laseroptek.raman.data.model.serial
 
 data class HandPiece(
-    val type:Int = 1  // ascii (00 ~ 99)
+    val type:Int = 0  // ascii (00 ~ 99)
 )

app/src/main/java/com/laseroptek/raman/ui/MainActivity.kt

@@ -260,9 +260,11 @@ class MainActivity : ComponentActivity() {
                     // This prevents serial interrupts from stealing CPU during the first frame.
                     delay(200)
 
-                    vm.txPacketOnce()
+                    // IMPORTANT:
-
+                    // rxPacketLoop() starts serial open() asynchronously.
+                    // Start RX first so txPacketOnce() is less likely to run before FD is ready.
                     vm.rxPacketLoop()
+                    vm.txPacketOnce()
                     vm.txPacketLoop()
 
                     Timber.d("System fully operational.")

app/src/main/java/com/laseroptek/raman/ui/screens/engineer/EngineerScreen.kt

@@ -1011,14 +1011,14 @@ fun EngineerScreen(
                     if (ok) {
                         Timber.d("onClick > lampCount: $value")
 
-                        mainViewModel.setLifeTime(
+                        engineerViewModel.setLifeTime(
                             lifeTime.copy(
                                 lamp = value
                             )
                         )
 
                         scope.launch {
-                            mainViewModel.saveLifeTimeToPreference()
+                            engineerViewModel.saveLifeTimeToPreference()
                         }
                     }
                     showLifeTimeLampCountPopup = false
@@ -1034,13 +1034,13 @@ fun EngineerScreen(
                 onClick = { ok, value ->
                     if (ok) {
                         Timber.d("onClick > hp5x5: $value")
-                        mainViewModel.setLifeTime(
+                        engineerViewModel.setLifeTime(
                             lifeTime.copy(
                                 hp5x5 = value
                             )
                         )
                         scope.launch {
-                            mainViewModel.saveLifeTimeToPreference()
+                            engineerViewModel.saveLifeTimeToPreference()
                         }
                     }
                     showLifeTypeHP5x5Popup = false
@@ -1056,13 +1056,13 @@ fun EngineerScreen(
                 onClick = { ok, value ->
                     if (ok) {
                         Timber.d("onClick > hp7x7: $value")
-                        mainViewModel.setLifeTime(
+                        engineerViewModel.setLifeTime(
                             lifeTime.copy(
                                 hp7x7 = value
                             )
                         )
                         scope.launch {
-                            mainViewModel.saveLifeTimeToPreference()
+                            engineerViewModel.saveLifeTimeToPreference()
                         }
                     }
                     showLifeTimeHP7x7Popup = false
@@ -1078,13 +1078,13 @@ fun EngineerScreen(
                 onClick = { ok, value ->
                     if (ok) {
                         Timber.d("onClick > hp10x10: $value")
-                        mainViewModel.setLifeTime(
+                        engineerViewModel.setLifeTime(
                             lifeTime.copy(
                                 hp10x10 = value
                             )
                         )
                         scope.launch {
-                            mainViewModel.saveLifeTimeToPreference()
+                            engineerViewModel.saveLifeTimeToPreference()
                         }
                     }
                     showLifeTimeHP10x10Popup = false
@@ -1100,13 +1100,13 @@ fun EngineerScreen(
                 onClick = { ok, value ->
                     if (ok) {
                         Timber.d("onClick > hp12x12: $value")
-                        mainViewModel.setLifeTime(
+                        engineerViewModel.setLifeTime(
                             lifeTime.copy(
                                 hp12x12 = value
                             )
                         )
                         scope.launch {
-                            mainViewModel.saveLifeTimeToPreference()
+                            engineerViewModel.saveLifeTimeToPreference()
                         }
                     }
                     showLifeTimeHP12x12Popup = false
@@ -1122,13 +1122,13 @@ fun EngineerScreen(
                 onClick = { ok, value ->
                     if (ok) {
                         Timber.d("onClick > hp3x15: $value")
-                        mainViewModel.setLifeTime(
+                        engineerViewModel.setLifeTime(
                             lifeTime.copy(
                                 hp3x15 = value
                             )
                         )
                         scope.launch {
-                            mainViewModel.saveLifeTimeToPreference()
+                            engineerViewModel.saveLifeTimeToPreference()
                         }
                     }
                     showLifeTimeHP3x15Popup = false
@@ -1143,13 +1143,13 @@ fun EngineerScreen(
                 onClick = { ok, value ->
                     if (ok) {
                         Timber.d("onClick > detector: $value")
-                        mainViewModel.setLifeTime(
+                        engineerViewModel.setLifeTime(
                             lifeTime.copy(
                                 detector = value
                             )
                         )
                         scope.launch {
-                            mainViewModel.saveLifeTimeToPreference()
+                            engineerViewModel.saveLifeTimeToPreference()
                         }
                     }
                     showLifeTimeDetectorPopup = false
@@ -1164,13 +1164,13 @@ fun EngineerScreen(
                 onClick = { ok, value ->
                     if (ok) {
                         Timber.d("onClick > water: $value")
-                        mainViewModel.setLifeTime(
+                        engineerViewModel.setLifeTime(
                             lifeTime.copy(
                                 water = value
                             )
                         )
                         scope.launch {
-                            mainViewModel.saveLifeTimeToPreference()
+                            engineerViewModel.saveLifeTimeToPreference()
                         }
                     }
                     showLifeTimeWaterPopup = false
@@ -1187,7 +1187,7 @@ fun EngineerScreen(
                 onClick = { ok, value ->
                     if (ok) {
                         Timber.d("onClick > ktp: $value")
-                        mainViewModel.setTemperatureWrite(
+                        engineerViewModel.setTemperatureWrite(
                             temperatureWrite.copy(
                                 ktp = value.toFloat()
                             )
@@ -1199,12 +1199,12 @@ fun EngineerScreen(
                             CMD.OVEN,
                             Oven(
                                 type = 0x41,
-                                ktp = temperatureWrite.ktp
+                                ktp = value.toFloat()
                             )
                         )
 
                         scope.launch {
-                            mainViewModel.saveTemeratureWriteToPreference()
+                            engineerViewModel.saveTemeratureWriteToPreference()
                         }
                     }
                     showTempKTPPopup = false
@@ -1220,13 +1220,13 @@ fun EngineerScreen(
                     if (ok) {
                         Timber.d("onClick > chamber1: $value")
 
-                        mainViewModel.setTemperatureWrite(
+                        engineerViewModel.setTemperatureWrite(
                             temperatureWrite.copy(
                                 chamber1 = value.toFloat()
                             )
                         )
                         scope.launch {
-                            mainViewModel.saveTemeratureWriteToPreference()
+                            engineerViewModel.saveTemeratureWriteToPreference()
                         }
                     }
                     showTempChamber1Popup = false
@@ -1241,13 +1241,13 @@ fun EngineerScreen(
                 onClick = { ok, value ->
                     if (ok) {
                         Timber.d("onClick > chamber2: $value")
-                        mainViewModel.setTemperatureWrite(
+                        engineerViewModel.setTemperatureWrite(
                             temperatureWrite.copy(
                                 chamber2 = value.toFloat()
                             )
                         )
                         scope.launch {
-                            mainViewModel.saveTemeratureWriteToPreference()
+                            engineerViewModel.saveTemeratureWriteToPreference()
                         }
                     }
                     showTempChamber2Popup = false
@@ -1261,13 +1261,13 @@ fun EngineerScreen(
                 count = temperatureWrite.water,
                 onClick = { ok, value ->
                     if (ok) {
-                        mainViewModel.setTemperatureWrite(
+                        engineerViewModel.setTemperatureWrite(
                             temperatureWrite.copy(
                                 water = value.toFloat()
                             )
                         )
                         scope.launch {
-                            mainViewModel.saveTemeratureWriteToPreference()
+                            engineerViewModel.saveTemeratureWriteToPreference()
                         }
                     }
                     showTempWaterPopup = false
@@ -1282,13 +1282,13 @@ fun EngineerScreen(
                 onClick = { ok, value ->
                     if (ok) {
                         Timber.d("onClick > basePlate: $value")
-                        mainViewModel.setTemperatureWrite(
+                        engineerViewModel.setTemperatureWrite(
                             temperatureWrite.copy(
                                 basePlate = value.toFloat()
                             )
                         )
                         scope.launch {
-                            mainViewModel.saveTemeratureWriteToPreference()
+                            engineerViewModel.saveTemeratureWriteToPreference()
                         }
                     }
                     showTempBaseplatePopup = false
@@ -1393,9 +1393,9 @@ fun EngineerScreen(
                         mainViewModel.saveLampCountToPreference()
                         mainViewModel.saveSprayDcdListToPreference()
                         mainViewModel.savePresetListToPreference()
-                        mainViewModel.saveLifeTimeToPreference()
+                        engineerViewModel.saveLifeTimeToPreference()
-                        mainViewModel.saveTemeratureWriteToPreference()
+                        engineerViewModel.saveTemeratureWriteToPreference()
-                        mainViewModel.saveEnergyMeasuredWriteToPreference()
+                        engineerViewModel.saveEnergyMeasuredWriteToPreference()
                         mainViewModel.saveEnergyRefer2ToPreference()
                         mainViewModel.saveProductSerialListToPreference()
                         mainViewModel.savePowerSupplySerialListToPreference()
@@ -1521,14 +1521,14 @@ fun EngineerScreen(
                 },
                 onClickSet = { v ->
                     // write measured value
-                    mainViewModel.setEnergyMeasuredWrite(
+                    engineerViewModel.setEnergyMeasuredWrite(
                         EnergyMeasured(
                             measured = v
                         )
                     )
 
                     scope.launch {
-                        mainViewModel.saveEnergyMeasuredWriteToPreference()
+                        engineerViewModel.saveEnergyMeasuredWriteToPreference()
                     }
 
                     /*
@@ -1733,4 +1733,4 @@ fun PreviewEngineerView(
         mainViewModel = mainViewModel,
         engineerViewModel = engineerViewModel
     )
-}
+}

app/src/main/java/com/laseroptek/raman/ui/screens/home/preset/PresetLoadPopup.kt

@@ -780,21 +780,25 @@ fun PresetLoadPopup(
                                 .noRippleClickable(onClick = {
                                     Timber.d("onClick - Preset Load")
 
-                                    val selectedPreset =
+                                    val selectedPreset = presetViewModel.getPreset(selectedPresetIndex)
-                                        presetViewModel.getPreset(selectedPresetIndex)
+                                    if (selectedPreset == null) {
-                                    val priority =
+                                        Timber.w("onClick - Preset Load: selectedPreset is null. index=$selectedPresetIndex")
-                                        selectedPreset?.priority ?: 0
+                                        return@noRippleClickable
+                                    }
+                                    val priority = selectedPreset.priority
 
                                     Timber.d("onClick - Preset Load ($priority)")
 
-//                                    if (priority > 0) {   // TODO : 검증 필요
+                                    if (priority > 0) {
                                         mainViewModel.setSelectedPresetIndex( priority )
                                         mainViewModel.applyPreset(priority)
-                                        presetViewModel.clearPreset()
+                                    } else {
-                                        onClick.invoke(false)
+                                        // 우선순위가 NONE인 경우, 인덱스 설정 X
-//                                    } else {
+                                        mainViewModel.setSelectedPresetIndex(0)
-//                                        Timber.d("SKIP - Preset Load ($priority)")
+                                        mainViewModel.applyPreset(selectedPreset)
-//                                    }
+                                    }
+                                    presetViewModel.clearPreset()
+                                    onClick.invoke(false)
                                 })
                                 .size(40.px.dp)
                                 .background(Color.Transparent)

app/src/main/java/com/laseroptek/raman/ui/screens/main/MainViewModel.kt

@@ -134,6 +134,7 @@ import kotlinx.coroutines.joinAll
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
 import timber.log.Timber
+import kotlin.math.abs
 import javax.inject.Inject
 import kotlin.experimental.or
 import kotlin.time.Duration.Companion.milliseconds
@@ -814,24 +815,62 @@ class MainViewModel @Inject constructor(
     }
 
     fun txPacketOnce() {
-        // viewModel init 으로 이동. 필요.
+        viewModelScope.launch(dispatcherProvider.io) {
-        // 경고 정보 조회 (주기적 heart beat)
+            // txPacketOnce is called during app startup.
-        // repeatOnLifecycle은 Activity가 포그라운드에 있을 때로 한정지어, 특정 Lifecycle이 Trigger 되었을 때 동작하도록 만드는 block 임.
+            // Because serial open() is started in rxPacketLoop() asynchronously,
+            // FD can still be -1 here (startup race). Wait briefly before first TX burst.
+            if (!waitUntilSerialReady()) {
+                Timber.e("txPacketOnce skipped: serial port is not ready (fd=%d)", serialPortRepository.getFD())
+                return@launch
+            }
 
-        // tx Version Read
+            // viewModel init 으로 이동. 필요.
-        txPacket(READ_WRITE.READ, CMD.VERSION, byteArrayOf(0x41.toByte()))
+            // 경고 정보 조회 (주기적 heart beat)
+            // repeatOnLifecycle은 Activity가 포그라운드에 있을 때로 한정지어, 특정 Lifecycle이 Trigger 되었을 때 동작하도록 만드는 block 임.
 
-        // tx Q-Switch Write
+            // tx Version Read
-        txPacket(READ_WRITE.WRITE, CMD.Q_SWITCH, qSwitch.value)
+            txPacket(READ_WRITE.READ, CMD.VERSION, byteArrayOf(0x41.toByte()))
 
-        // tx Guide Beam Write
+            // tx Q-Switch Write
-        txPacket(READ_WRITE.WRITE, CMD.GUIDE_BEAM, GuideBeam(value = guideBeam.value.toInt()))
+            txPacket(READ_WRITE.WRITE, CMD.Q_SWITCH, qSwitch.value)
 
-        // tx DCD_GAS Write (DEFAULT VALUE)
+            // tx Oven Write (align with Engineer KTP write source)
-        txPacket(READ_WRITE.WRITE, CMD.DCD_GAS, dcdGas.value.copy(status = 0x50))
+            txPacket(READ_WRITE.WRITE, CMD.OVEN, Oven(ktp = temperature_write.value.ktp))
 
-        // tx SPRAY_DCD Write (DEFAULT VALUE)
+            // tx Guide Beam Write
-        txPacket(READ_WRITE.WRITE, CMD.SPRAY_DCD, sprayDcd.value.copy(status = 0x41))
+            txPacket(READ_WRITE.WRITE, CMD.GUIDE_BEAM, GuideBeam(value = getGuideBeamTxValue()))
+
+            // tx DCD_GAS Write (DEFAULT VALUE)
+            txPacket(READ_WRITE.WRITE, CMD.DCD_GAS, dcdGas.value.copy(status = 0x50))
+
+            // tx SPRAY_DCD Write (DEFAULT VALUE)
+            txPacket(READ_WRITE.WRITE, CMD.SPRAY_DCD, sprayDcd.value.copy(status = 0x41))
+        }
+    }
+
+    private suspend fun waitUntilSerialReady(
+        timeoutMillis: Long = 2000L,
+        pollIntervalMillis: Long = 20L
+    ): Boolean {
+        // Poll FD until open() completes, with a bounded timeout to avoid blocking forever.
+        val start = System.currentTimeMillis()
+        while (System.currentTimeMillis() - start < timeoutMillis) {
+            if (serialPortRepository.getFD() != -1) return true
+            delay(pollIntervalMillis)
+        }
+        return serialPortRepository.getFD() != -1
+    }
+
+    // Guide Beam step mapping (0~10)
+    // 0 -> fixed 0
+    // 1~10 -> min~max range in 10 steps (10 -> max)
+    private fun getGuideBeamTxValue(): Int {
+        val step = guideBeam.value.toInt().coerceIn(0, 10)
+        return if (step == 0) {
+            0
+        } else {
+            guideBeamMin.value + ((step - 1) * (guideBeamMax.value - guideBeamMin.value) / 9)
+        }
     }
 
     // Example: Emitting an event after a delay
@@ -2043,28 +2082,59 @@ class MainViewModel @Inject constructor(
         Timber.d("preset: ${preset}")
 
         val newPreset = if (preset == null) {
+            val defaultPulseWidth = PulseDurations.first()
             Preset(
                 handPieceType = handPiece.value.type,
                 priority = priority,
-                fluence = energyTable.value.getKey2ListForKey1(0.5f).first(),
+                fluence = energyTable.value.getKey2ListForKey1(defaultPulseWidth).firstOrNull() ?: 0f,
                 repetition = repetitionList.value.first(),
-                pulseWidth = PulseDurations.first(),
+                pulseWidth = defaultPulseWidth,
             )
         } else {
             preset
         }
+        applyPreset(newPreset)
+    }
 
-        val fluenceList = energyTable.value.getKey2ListForKey1(newPreset.pulseWidth)
+    fun applyPreset(preset: Preset) {
+        val newPreset = preset.copy()
 
         val pulseStep = PulseDurations.indexOf(newPreset.pulseWidth).takeIf {it != -1} ?: 0
-        val fluenceStep = fluenceList.indexOf(newPreset.fluence).takeIf {it != -1} ?: 0
+        val resolvedPulseWidth = PulseDurations[pulseStep]
-        val repetitionStep = repetitionList.value.indexOf(newPreset.repetition).takeIf {it != -1} ?: 0
+
+        // 프리셋의 pulseWidth 기준으로 실제 사용 가능한 fluence 목록을 먼저 동기화한다.
+        val newFluenceList = energyTable.value.getKey2ListForKey1(resolvedPulseWidth)
+        if (newFluenceList != fluenceList.value) {
+            setFluenceList(newFluenceList)
+        }
+
+        // 프리셋 fluence가 정확히 없을 수 있으므로, 가장 가까운 값으로 보정한다.
+        val resolvedFluence = newFluenceList.minByOrNull { abs(it - newPreset.fluence) }
+            ?: newFluenceList.firstOrNull()
+            ?: 0f
+        val fluenceStep = newFluenceList.indexOf(resolvedFluence).takeIf { it != -1 } ?: 0
+
+        // 보정된 (pulseWidth, fluence) 조합으로 repetition 테이블을 다시 계산한다.
+        val hzType = hzTable.value.getValue(resolvedPulseWidth, resolvedFluence)
+        val newRepetitionList = RepetitionsByColorKey[hzType] ?: RepetitionsByColorKey[KEY_YELLOW]!!
+        if (newRepetitionList != repetitionList.value) {
+            setRepetitionList(newRepetitionList)
+        }
+        val repetitionStep = newRepetitionList.indexOf(newPreset.repetition).takeIf { it != -1 } ?: 0
 
         Timber.d("pulseStep: ${pulseStep} fluenceStep: ${fluenceStep} repetitionStep: ${repetitionStep}")
 
         val pulseAngle = pulseStep.stepToDegree(totalSteps = PulseDurations.size)
-        val fluenceAngle = fluenceStep.stepToDegree(totalSteps = fluenceList.size)
+        val fluenceAngle = if (newFluenceList.isNotEmpty()) {
-        val repetitionAngle = repetitionStep.stepToDegree(totalSteps = repetitionList.value.size)
+            fluenceStep.stepToDegree(totalSteps = newFluenceList.size)
+        } else {
+            0f
+        }
+        val repetitionAngle = if (newRepetitionList.isNotEmpty()) {
+            repetitionStep.stepToDegree(totalSteps = newRepetitionList.size)
+        } else {
+            0f
+        }
 
         Timber.d("pulseStep: ${pulseStep} fluenceStep: ${fluenceStep} repetitionStep: ${repetitionStep}")
 
@@ -2094,8 +2164,15 @@ class MainViewModel @Inject constructor(
             setFluenceList(newFluenceList)
         }
 
+        // 2-1. Resolve and apply fluence by value (not by old angle/index).
+        val resolvedFluence = newFluenceList.minByOrNull { abs(it - newFluence) } ?: 0f
+        val resolvedFluenceIndex = newFluenceList.indexOf(resolvedFluence).takeIf { it >= 0 } ?: 0
+        if (newFluenceList.isNotEmpty()) {
+            setFluenceAngle(resolvedFluenceIndex.stepToDegree(totalSteps = newFluenceList.size))
+        }
+
         // 3. Safely Update Repetition List (Prevents NullPointerException)
-        val newHzType = hzTable.value.getValue(newPulseDuration, newFluence)
+        val newHzType = hzTable.value.getValue(newPulseDuration, resolvedFluence)
         val newRepetitionList = RepetitionsByColorKey[newHzType] ?: RepetitionsByColorKey[KEY_YELLOW]!!
         if (newRepetitionList != repetitionList.value) {
             setRepetitionList(newRepetitionList)
@@ -2130,7 +2207,7 @@ class MainViewModel @Inject constructor(
         // 6. Any change invalidates the current preset selection.
         setSelectedPresetIndex(0)
 
-        Timber.d("Updated Laser Parameters: pulse=$newPulseDuration, fluence=$newFluence -> newRepListSize=${newRepetitionList.size}")
+        Timber.d("Updated Laser Parameters: pulse=$newPulseDuration, fluence=$resolvedFluence -> newRepListSize=${newRepetitionList.size}")
     }
 
     /**
@@ -2150,13 +2227,16 @@ class MainViewModel @Inject constructor(
         setPulseAngle(newPulseStep.stepToDegree(totalSteps = PulseDurations.size))
 
         val newPulseDuration = PulseDurations[newPulseStep]
-        // When pulse duration changes via slider, we use the first available fluence for the new list.
+        // Keep the current fluence value when pulse duration changes via slider.
-        val firstFluence = energyTable.value.getKey2ListForKey1(newPulseDuration).firstOrNull() ?: 0f
+        val currentFluenceStep = fluenceAngle.value.degreeToStep(totalSteps = fluenceList.value.size)
+        val currentFluence = fluenceList.value.getOrNull(currentFluenceStep)
+            ?: energyTable.value.getKey2ListForKey1(newPulseDuration).firstOrNull()
+            ?: 0f
 
-        // Call the centralized helper, resetting the fluence slider.
+        // Call the centralized helper using the preserved fluence value.
         updateLaserParameters(
             newPulseDuration = newPulseDuration,
-            newFluence = firstFluence,
+            newFluence = currentFluence,
         )
     }
 
@@ -2168,12 +2248,17 @@ class MainViewModel @Inject constructor(
             setPulseAngle(newStep.stepToDegree(totalSteps = PulseDurations.size))
 
             val newPulseDuration = PulseDurations[newStep]
-            val firstFluence = energyTable.value.getKey2ListForKey1(newPulseDuration).firstOrNull() ?: 0f
+            // Keep the current fluence value when pulse duration changes via slider.
+            val currentFluenceStep = fluenceAngle.value.degreeToStep(totalSteps = fluenceList.value.size)
+            val currentFluence = fluenceList.value.getOrNull(currentFluenceStep)
+                ?: energyTable.value.getKey2ListForKey1(newPulseDuration).firstOrNull()
+                ?: 0f
+
 
             // Call the centralized helper, resetting the fluence slider.
             updateLaserParameters(
                 newPulseDuration = newPulseDuration,
-                newFluence = firstFluence,
+                newFluence = currentFluence,
             )
         }
     }

app/src/main/java/com/laseroptek/raman/utils/ext/PacketExtension.kt

@@ -487,7 +487,7 @@ fun QSwitch.toByteArray(): ByteArray {
     val delayTimeIntegerPart = this.delayTime.toInt()
     val delayTimeFractionPart = ((this.delayTime - delayTimeIntegerPart) * 10).toInt()
     val intervalTimeIntegerPart = this.intervalTime.toInt()
-    val intervalTimeFractionPart = ((this.intervalTime - delayTimeIntegerPart) * 10).toInt()
+    val intervalTimeFractionPart = ((this.intervalTime - intervalTimeIntegerPart) * 10).toInt()
 
     val delayTimeArray = byteArrayOf(
         ((delayTimeIntegerPart.getNthDigit(2) + 0x30) and 0xFF).toByte(),

docs/change_summary_2026-03-04.md

@@ -0,0 +1,23 @@
+# 변경 요약 (2026-03-04)
+
+이 문서는 현재 `git diff` 기준으로 반영된 변경을 정리합니다.
+
+## 1) 시리얼 초기 전송 누락(Startup race) 대응
+
+### 변경 파일
+- `app/src/main/java/com/laseroptek/raman/ui/MainActivity.kt`
+- `app/src/main/java/com/laseroptek/raman/ui/screens/main/MainViewModel.kt`
+
+### 변경 내용
+- `MainActivity.initialize()`의 시리얼 시작 순서를 조정
+  - 이전: `txPacketOnce()` -> `rxPacketLoop()` -> `txPacketLoop()`
+  - 이후: `rxPacketLoop()` -> `txPacketOnce()` -> `txPacketLoop()`
+- `MainViewModel.txPacketOnce()`를 코루틴(IO)에서 실행하도록 변경
+- `waitUntilSerialReady()` 추가
+  - 최대 2초 동안 20ms 간격으로 `FD != -1` 확인
+  - 준비 실패 시 에러 로그 후 초기 TX 중단
+- 관련 설명 주석 추가
+
+### 의도/효과
+- 앱 시작 직후 `open()` 완료 전 TX가 먼저 발생하는 레이스를 완화/방어
+- 포트 미준비 상태(`FD == -1`)에서 write가 호출되어 초기 패킷이 누락되는 문제를 줄임

docs/serial_tx_startup_race.md

@@ -0,0 +1,41 @@
+# Serial TX Startup Race 정리
+
+## 1) FD(File Descriptor)란?
+- `FD`는 리눅스/안드로이드에서 열린 리소스(파일/소켓/시리얼 포트)를 가리키는 정수 핸들입니다.
+- 이 프로젝트에서 시리얼 포트 상태는 다음처럼 판단합니다.
+  - `FD == -1`: 포트 미오픈(유효하지 않음)
+  - `FD >= 0`: 포트 오픈 완료(유효)
+- 따라서 `FD == -1` 상태에서 `write()`를 호출하면 실제 시리얼 전송이 되지 않습니다.
+
+## 2) 문제 원인
+- `txPacketOnce()`가 앱 시작 직후 실행됩니다.
+- 시리얼 포트 `open()`은 `rxPacketLoop()` 내부에서 코루틴으로 비동기 시작됩니다.
+- 기존 순서에서 `txPacketOnce()`가 먼저 호출되면, 포트 오픈 완료 전(`FD == -1`)에 TX가 시도되어 초기 패킷 전송이 누락될 수 있습니다.
+
+## 3) 적용한 수정
+
+### A. 초기 호출 순서 조정
+- 파일: `app/src/main/java/com/laseroptek/raman/ui/MainActivity.kt`
+- 변경:
+  - 이전: `txPacketOnce()` -> `rxPacketLoop()` -> `txPacketLoop()`
+  - 이후: `rxPacketLoop()` -> `txPacketOnce()` -> `txPacketLoop()`
+- 목적: RX 루프가 먼저 포트 오픈을 시작하도록 해서 초기 TX 레이스 확률을 줄임
+
+### B. `txPacketOnce()`에 포트 준비 대기 추가
+- 파일: `app/src/main/java/com/laseroptek/raman/ui/screens/main/MainViewModel.kt`
+- 변경:
+  - `txPacketOnce()`를 IO 코루틴에서 실행
+  - `waitUntilSerialReady()`(최대 2초, 20ms 폴링)로 `FD != -1` 확인 후 TX 진행
+  - 시간 내 준비 실패 시 로그를 남기고 전송 중단
+- 목적: 순서만으로 보장되지 않는 코루틴 스케줄링 레이스를 방어
+
+## 4) 왜 TX에서 직접 open()하지 않았는가?
+- 현재 구조에서 `open()`의 데이터 콜백은 `rxPacketLoop()`의 `callbackFlow`와 연결됩니다.
+- TX 경로에서 별도 `open()`을 하면 중복 오픈/콜백 소유권/FD 교체 타이밍 이슈가 생길 수 있습니다.
+- 안정적인 패턴은:
+  - 포트 오픈 책임: RX(단일 지점)
+  - 포트 사용(TX): ready 확인 후 write
+
+## 5) 확인 포인트
+- 앱 시작 직후 로그에서 `FD`가 유효해진 뒤 `txPacketOnce()`의 TX 로그가 출력되는지 확인
+- 장비 측 시리얼 모니터에서 초기 패킷(Version/Q-Switch/GuideBeam/DCD/SprayDCD) 수신 여부 확인