Iterable setup settings with encoder

To make setup settings configurable make it possible to select them
first. Therefore the `setup_state` enum is created to keep track of
the currently selected setting state.

firmware/src/main.c

@@ -93,6 +93,7 @@ enum input {cw, ccw, click, hold};
 
 static volatile enum state {home, ch1, ch2, ch3, setup} current_state = home;
 static volatile enum state home_state = ch1;
+static volatile enum setup_state {contrast, backlight, back} setup_state = contrast;
 
 static volatile uint8_t enc = 0;
 
@@ -329,6 +330,22 @@ static void lcd_home(void) {
 static void lcd_setup(void) {
     lcd_fill(0x00);
 
+    bool contrast_selected = false;
+    bool backlight_selected = false;
+    bool back_selected = false;
+
+    switch (setup_state) {
+    case contrast:
+        contrast_selected = true;
+        break;
+    case backlight:
+        backlight_selected = true;
+        break;
+    default: // back
+        back_selected = true;
+        break;
+    }
+
     for (uint8_t i = 0; i < 2; i++) {
         SPI_PORT &= ~(1 << LCD_CD);
         lcd_write(0x00);
@@ -374,7 +391,8 @@ static void lcd_setup(void) {
         lcd_write_kerning(2, false);
         lcd_write_symbol_page(&sym_colon, i, false);
         lcd_write_kerning(11, false);
-        lcd_write_integer_page(123, 1, i, false);
+        lcd_write_integer_page(123, 1, i, contrast_selected);
+        lcd_write_kerning(2, contrast_selected);
     }
 
     for (uint8_t i = 0; i < 2; i++) {
@@ -404,23 +422,26 @@ static void lcd_setup(void) {
         lcd_write_kerning(2, false);
         lcd_write_symbol_page(&sym_colon, i, false);
         lcd_write_kerning(7, false);
-        lcd_write_integer_page(123, 3, i, false);
+        lcd_write_integer_page(123, 3, i, backlight_selected);
+        lcd_write_kerning(2, backlight_selected);
     }
 
     for (uint8_t i = 0; i < 2; i++) {
         SPI_PORT &= ~(1 << LCD_CD);
-        lcd_write(0x03);
+        lcd_write(0x01);
         lcd_write(0x12);
         lcd_write(0xB6 + i);
         SPI_PORT |= (1 << LCD_CD);
 
-        lcd_write_symbol_page(&sym_b, i, false);
+        lcd_write_kerning(2, back_selected);
-        lcd_write_kerning(2, false);
+        lcd_write_symbol_page(&sym_b, i, back_selected);
-        lcd_write_symbol_page(&sym_a, i, false);
+        lcd_write_kerning(2, back_selected);
-        lcd_write_kerning(2, false);
+        lcd_write_symbol_page(&sym_a, i, back_selected);
-        lcd_write_symbol_page(&sym_c, i, false);
+        lcd_write_kerning(2, back_selected);
-        lcd_write_kerning(2, false);
+        lcd_write_symbol_page(&sym_c, i, back_selected);
-        lcd_write_symbol_page(&sym_k, i, false);
+        lcd_write_kerning(2, back_selected);
+        lcd_write_symbol_page(&sym_k, i, back_selected);
+        lcd_write_kerning(2, back_selected);
     }
 }
 
@@ -437,6 +458,7 @@ static void change_state(enum state new_state) {
     case ch3:
         break;
     case setup:
+        setup_state = contrast;
         lcd_setup();
         current_state = setup;
         break;
@@ -468,10 +490,27 @@ static void update_home(enum input event) {
 static void update_setup(enum input event) {
     switch (event) {
     case cw:
+        setup_state++;
+        if (setup_state > back)
+            setup_state = contrast;
+        lcd_setup();
         break;
     case ccw:
+        setup_state--;
+        if (setup_state > back)
+            setup_state = back;
+        lcd_setup();
         break;
     case click:
+        switch (setup_state) {
+        case contrast:
+            break;
+        case backlight:
+            break;
+        case back:
+            change_state(home);
+            break;
+        }
         break;
     case hold:
         change_state(home);