improve cyd backlight dimming (reduced flicker)

compile_commands.json

-.pio/build/lorarx/compile_commands.json
+.pio/build/cyd/compile_commands.json

platformio.ini

 board = esp32dev
 framework = arduino
 upload_protocol = esptool
-upload_port = /dev/ttyUSB2
-monitor_port = /dev/ttyUSB2
+upload_port = /dev/ttyUSB1
+monitor_port = /dev/ttyUSB1
 monitor_speed = 115200
 extra_scripts = pre:extra_script.py
 build_flags =

src/ui.cpp

 #define LDR_CHECK_MS 100
 #define LDR_DARK_VALUE 1200
 #define LDR_BRIGHT_VALUE 0
-#define LDR_LOWPASS_FACT 0.025f
+#define LDR_LOWPASS_FACT 0.01f
 
 #define STANDBY_BRIGHTNESS 10
 #define LCD_MIN_BRIGHTNESS (STANDBY_BRIGHTNESS * 2)
 static enum ui_pages ui_page = UI_START;
 static bool is_touched = false;
 static unsigned long last_ldr = 0;
-static int ldr_value = 0;
+static float ldr_value = 0;
 static unsigned long last_touch_time = 0;
 static int curr_brightness = LCD_MAX_BRIGHTNESS;
 static int set_max_brightness = LCD_MAX_BRIGHTNESS;
     // read out LDR in regular intervals
     if (now >= (last_ldr + LDR_CHECK_MS)) {
         last_ldr = now;
-        int ldr = analogRead(LDR_PIN);
+        float ldr = analogRead(LDR_PIN);
 
         ldr_value = (ldr_value * (1.0f - LDR_LOWPASS_FACT)) + (ldr * LDR_LOWPASS_FACT);