fix: resolve flickering issue when updating

closes #179

Author: ph1p

include/constants.h

@@ -66,4 +66,4 @@ enum SYSTEM_STATUS
   LOADING,
 };
 
-extern SYSTEM_STATUS currentStatus;
+extern volatile SYSTEM_STATUS currentStatus;

include/screen.h

@@ -33,7 +33,7 @@ class Screen_
       0xef, 0xee, 0xed, 0xec, 0xeb, 0xea, 0xe9, 0xe8, 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff};
 
   static void onScreenTimer();
-  ICACHE_RAM_ATTR void _render();
+  void _render();
   void rotate();
   uint8_t *getRotatedRenderBuffer();
 

src/main.cpp

@@ -54,7 +54,11 @@ unsigned long previousMillis = 0;
 unsigned long interval = 30000;
 
 PluginManager pluginManager;
-SYSTEM_STATUS currentStatus = NONE;
+#ifdef ESP32
+DRAM_ATTR volatile SYSTEM_STATUS currentStatus = NONE;
+#else
+volatile SYSTEM_STATUS currentStatus = NONE;
+#endif
 WiFiManager wifiManager;
 
 unsigned long lastConnectionAttempt = 0;

src/ota.cpp

@@ -12,11 +12,12 @@ void onOTAStart()
   Serial.println("OTA update started!");
   currentStatus = UPDATE;
 
+  Screen.clear();
   std::vector<int> bits = Screen.readBytes(letterU);
 
   for (int i = 0; i < bits.size(); i++)
   {
-    Screen.setPixelAtIndex(i, bits[i]);
+    Screen.setPixelAtIndex(i, bits[i], MAX_BRIGHTNESS);
   }
 }
 
@@ -41,6 +42,7 @@ void onOTAEnd(bool success)
   {
     Serial.println("There was an error during OTA update!");
   }
+
   std::vector<int> bits = Screen.readBytes(letterR);
 
   for (int i = 0; i < bits.size(); i++)
@@ -53,6 +55,7 @@ void onOTAEnd(bool success)
 #else
   delay(1000);
 #endif
+
   currentStatus = NONE;
   Screen.loadFromStorage();
 }

src/screen.cpp

@@ -187,7 +187,7 @@ void Screen_::setCurrentRotation(int rotation, bool shouldPersist)
 #endif
 }
 
-uint8_t *Screen_::getRotatedRenderBuffer()
+IRAM_ATTR uint8_t *Screen_::getRotatedRenderBuffer()
 {
   // No rotation needed - return original buffer directly
   if (currentRotation == 0)
@@ -206,7 +206,7 @@ uint8_t *Screen_::getRotatedRenderBuffer()
   return rotatedRenderBuffer_;
 }
 
-void Screen_::rotate()
+IRAM_ATTR void Screen_::rotate()
 {
   if (currentRotation == 1)
   {
@@ -244,14 +244,14 @@ void Screen_::rotate()
   }
 }
 
-void Screen_::onScreenTimer()
+IRAM_ATTR void Screen_::onScreenTimer()
 {
   Screen._render();
 }
 
-ICACHE_RAM_ATTR void Screen_::_render()
+IRAM_ATTR void Screen_::_render()
 {
-  const auto buf = getRotatedRenderBuffer();
+  const auto buf = (currentStatus == UPDATE) ? renderBuffer_ : getRotatedRenderBuffer();
 
   // SPI data needs to be 32-bit aligned, round up before divide
   static unsigned long
@@ -261,13 +261,26 @@ ICACHE_RAM_ATTR void Screen_::_render()
 
   static unsigned char counter = 0;
 
-  for (int idx = 0; idx < ROWS * COLS; idx++)
+  if (currentStatus == UPDATE)
   {
-    uint16_t scaledValue = ((uint16_t)buf[positions[idx]] * brightness_) / MAX_BRIGHTNESS;
-    bits[idx >> 3] |= (scaledValue > counter ? 0x80 : 0) >> (idx & 7);
+    for (int idx = 0; idx < ROWS * COLS; idx++)
+    {
+      if (buf[positions[idx]] > 0)
+      {
+        bits[idx >> 3] |= (0x80 >> (idx & 7));
+      }
+    }
+  }
+  else
+  {
+    // Normal rendering with PWM for grayscale
+    for (int idx = 0; idx < ROWS * COLS; idx++)
+    {
+      uint16_t scaledValue = ((uint16_t)buf[positions[idx]] * brightness_) / MAX_BRIGHTNESS;
+      bits[idx >> 3] |= (scaledValue > counter ? 0x80 : 0) >> (idx & 7);
+    }
+    counter += ((MAX_BRIGHTNESS + 1) / GRAY_LEVELS);
   }
-
-  counter += ((MAX_BRIGHTNESS + 1) / GRAY_LEVELS);
 
   digitalWrite(PIN_LATCH, LOW);
   SPI.writeBytes(bits, sizeof(spi_bits));