Add backlight control over PWM

SW/Backlight.h

+#pragma once
+
+#include <avr/io.h>
+#include <stdint.h>
+
+// (0 až 100) ^2 * 6.5535
+const uint16_t log_scale[] = {
+        0, 7, 26, 59, 105, 164, 236, 321, 419, 531, 655, 793, 944,
+        1108, 1284, 1475, 1678, 1894, 2123, 2366, 2621, 2890, 3172, 3467, 3775, 4096, 4430,
+        4778, 5138, 5511, 5898, 6298, 6711, 7137, 7576, 8028, 8493, 8972, 9463, 9968, 10486,
+        11016, 11560, 12117, 12688, 13271, 13867, 14477, 15099, 15735, 16384, 17046, 17721,
+        18409, 19110, 19824, 20552, 21292, 22046, 22813, 23593, 24386, 25192, 26011, 26843,
+        27689, 28547, 29419, 30303, 31201, 32112, 33036, 33973, 34924, 35887, 36863, 37853,
+        38856, 39871, 40900, 41942, 42998, 44066, 45147, 46241, 47349, 48470, 49603, 50750,
+        51910, 53083, 54270, 55469, 56681, 57907, 59145, 60397, 61662, 62940, 64231, 65535
+    };
+
+class Backlight
+{
+    private:
+        uint8_t intensity;
+
+    public:
+        Backlight()
+        {
+            PORTD.DIRSET = PIN1_bm;
+
+            //Prescaller 2
+            TCD0.CTRLA = TC_CLKSEL_DIV2_gc;
+
+            //PWM on PIN1 and Sigle Slope PWM
+            TCD0.CTRLB = TC0_CCBEN_bm | TC_WGMODE_SS_gc;
+        }
+
+        void set_duty(uint16_t duty) { TCD0.CCB = duty; }
+
+        uint16_t get_duty() { return TCD0.CCB; }
+
+        void set_intensity(uint8_t intensity)
+        {
+            if (intensity > 100) intensity = 100;
+
+            TCD0.CCB = log_scale[intensity];
+
+            this->intensity = intensity;
+        }
+
+        uint8_t get_intensity() { return intensity; }
+};

SW/CMakeLists.txt

@@ -45,6 +45,7 @@ set(SOURCE_FILES
         SafeSolderingStation.h
         Uart.cpp
         Uart.h
+        Backlight.h
 )
 
 add_avr_executable(safe-soldering-station ${SOURCE_FILES})

SW/SafeSolderingStation.cpp

@@ -12,11 +12,11 @@ const HD44780_config lcd_config = {PORTD, PIN2_bm, PIN3_bm, PIN4_bm, PIN5_bm, PI
 SafeSolderingStation sss;
 
 SafeSolderingStation::SafeSolderingStation() : led(PORTD, PIN0_bm),
-                                               backlight(PORTD, PIN1_bm),
                                                heating(PORTC, PIN0_bm),
                                                enc(),
                                                lcd(lcd_config),
-                                               uart()
+                                               uart(),
+                                               backlight()
 {
 
 }
@@ -64,7 +64,6 @@ void SafeSolderingStation::init()
     uart.init();
     lcd.init();
     irq_init();
-    backlight.on();
 }
 
 void SafeSolderingStation::wellcome()
@@ -104,3 +103,18 @@ void SafeSolderingStation::test_encoder()
         enc.event = false;
     }
 }
+
+void SafeSolderingStation::test_backlight()
+{
+    if (enc.event)
+    {
+        if (enc.count >= 3) intensity++;
+        if (enc.count <= -3) intensity--;
+
+        enc.count  = 0;
+
+        backlight.set_intensity(intensity);
+        lcd.gotoxy_new(0,6);
+        lcd.write_num(backlight.get_intensity());
+    }
+}

SW/SafeSolderingStation.h

@@ -6,6 +6,7 @@
 #include "HD44780.h"
 #include "encoder.h"
 #include "Uart.h"
+#include "Backlight.h"
 
 class SafeSolderingStation
 {
@@ -15,14 +16,16 @@ class SafeSolderingStation
         void misc_pin_init();
         void irq_init();
 
+        uint8_t intensity;
+
     public:
         //Objects
         output led;
-        output backlight;
         output heating;
         encoder enc;
         HD44780 lcd;
         Uart uart;
+        Backlight backlight;
 
         //Methods
         SafeSolderingStation();
@@ -31,6 +34,7 @@ class SafeSolderingStation
         void wellcome();
 
         void test_encoder();
+        void test_backlight();
 };
 
 //Global instance

SW/main.cpp

@@ -11,9 +11,13 @@ int main()
     sss.init();
     sss.wellcome();
 
+    sss.lcd.gotoxy_new(0,0);
+    sss.lcd.write_text("Duty:      %");
+
     for(;;)
     {
-        sss.test_encoder();
+        //sss.test_encoder();
+        sss.test_backlight();
         _delay_ms(50);
     }
 }