Fix large-range spectrum stability and manual dB floor behavior

App/app/spectrum.c

@@ -645,10 +645,10 @@ static void UpdateScanInfo()
     if (scanInfo.rssi < scanInfo.rssiMin)
     {
         scanInfo.rssiMin = scanInfo.rssi;
-        if (!manualSetFlag) {
-            settings.dbMin = Rssi2DBm(scanInfo.rssiMin);
-            redrawStatus = true;
-        }
+        settings.dbMin = Rssi2DBm(scanInfo.rssiMin);
+        if (settings.dbMin > settings.dbMax - 10)
+            settings.dbMin = settings.dbMax - 10;
+        redrawStatus = true;
     }
 }
 
@@ -707,24 +707,50 @@ static void UpdatePeakInfo()
         UpdatePeakInfoForce();
 }
 
-static void SetRssiHistory(uint16_t idx, uint16_t rssi)
+static uint8_t GetHistorySlot(uint16_t idx)
 {
 #ifdef ENABLE_SCAN_RANGES
-    if (scanInfo.measurementsCount > 128)
+    if (scanInfo.measurementsCount > ARRAY_SIZE(rssiHistory))
     {
-        uint8_t i = (uint32_t)ARRAY_SIZE(rssiHistory) * 1000 / scanInfo.measurementsCount * idx / 1000;
-        if (rssiHistory[i] < rssi || isListening)
-            rssiHistory[i] = rssi;
-        rssiHistory[(i + 1) % 128] = 0;
+        uint32_t slot = (uint32_t)idx * ARRAY_SIZE(rssiHistory) / scanInfo.measurementsCount;
+        if (slot >= ARRAY_SIZE(rssiHistory))
+            slot = ARRAY_SIZE(rssiHistory) - 1;
+        return (uint8_t)slot;
+    }
+#endif
+    return (uint8_t)idx;
+}
+
+static void SetRssiHistory(uint16_t idx, uint16_t rssi)
+{
+    uint8_t slot = GetHistorySlot(idx);
+
+    if (rssi == RSSI_MAX_VALUE)
+    {
+        rssiHistory[slot] = RSSI_MAX_VALUE;
+        return;
+    }
+
+#ifdef ENABLE_SCAN_RANGES
+    if (scanInfo.measurementsCount > ARRAY_SIZE(rssiHistory))
+    {
+        uint16_t prev = rssiHistory[slot];
+        if (prev == RSSI_MAX_VALUE)
+            return;
+        // For large ranges: keep fast attack, soften decay to reduce flicker.
+        if (rssi >= prev)
+            rssiHistory[slot] = rssi;
+        else
+            rssiHistory[slot] = (uint16_t)((3u * prev + rssi) >> 2);
         return;
     }
 #endif
     // Attack/decay: instant rise, fast fall for stable display
-    uint16_t prev = rssiHistory[idx];
+    uint16_t prev = rssiHistory[slot];
     if (rssi >= prev) {
-        rssiHistory[idx] = rssi;              // Attack: instant
+        rssiHistory[slot] = rssi;              // Attack: instant
     } else {
-        rssiHistory[idx] = (prev + rssi) >> 1; // Decay: halve the gap each sweep
+        rssiHistory[slot] = (prev + rssi) >> 1; // Decay: halve the gap each sweep
     }
 }
 
@@ -1646,8 +1672,11 @@ static void RenderStatus()
 
 static void RenderSpectrum()
 {
+    uint16_t steps = GetStepsCount();
+    uint8_t arrowX = (steps > 1) ? (uint8_t)(128u * peak.i / (steps - 1)) : 0;
+
     DrawTicks();
-    DrawArrow(128u * peak.i / (GetStepsCount() - 1));
+    DrawArrow(arrowX);
     DrawSpectrum();
     DrawRssiTriggerLevel();
     DrawF(peak.f);
@@ -1804,7 +1833,9 @@ static bool HandleUserInput()
 
 static void Scan()
 {
-    if (rssiHistory[scanInfo.i] != RSSI_MAX_VALUE
+    uint8_t slot = GetHistorySlot(scanInfo.i);
+
+    if (rssiHistory[slot] != RSSI_MAX_VALUE
 #ifdef ENABLE_SCAN_RANGES
         && !IsBlacklisted(scanInfo.i)
 #endif