Furbish code and comment

Remove unneeded brackets and improve comment.

firmware/src/main.c

@@ -16,8 +16,8 @@
 #define ENC_A (PINB & (1 << PB6))
 #define ENC_B (PINB & (1 << PB7))
 
-uint8_t EEMEM eeprom_contrast = 0;
+uint8_t EEMEM eeprom_contrast = 8;
-uint8_t EEMEM eeprom_backlight = 0;
+uint8_t EEMEM eeprom_backlight = 1;
 
 static const uint8_t sacred_chao[200] = { 0x00, 0x00, 0x00, 0x00, 0x80, 0xC0, 0xE0, 0xF0, 0xF0, 0xF8, 0xFC, 0xFC, 0xFE, 0xFE, 0xFE, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0xFE, 0xFE, 0xFC, 0xFC, 0xF8, 0xF0, 0xF0, 0xE0, 0xC0, 0x80, 0x00, 0x00, 0x00, 0x00,
                                           0x80, 0xF0, 0xFC, 0xFE, 0xFF, 0xFF, 0x7F, 0x3F, 0x1F, 0x3F, 0x3F, 0x7F, 0x7F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x7F, 0x1F, 0x0F, 0x0F, 0x07, 0x07, 0x07, 0x03, 0xC3, 0xE3, 0x73, 0x37, 0x17, 0x07, 0x0F, 0x1E, 0x3C, 0xF0, 0x80,
@@ -137,10 +137,29 @@ void lcd_init(void) {
     lcd_write(0x2F); // (5)  Set Power Control: Booster, Regulator and Follower on
     lcd_write(0x27); // (8)  Set VLCD Resistor Ratio: Set Contrast
     lcd_write(0x81); // (9)  Set Electronic Volume: Set Contrast
-    lcd_write(0x10); // (9)  Set Electronic Volume: Set Contrast
+    lcd_write(value_contrast); // (9)  Set Electronic Volume: Set Contrast
     lcd_write(0xAF); // (12) Set Display Enable: Display on
 }
 
+void lcd_update_contrast(void) {
+    SPI_PORT &= ~(1 << LCD_CD);
+    lcd_write(0x81); // (9)  Set Electronic Volume: Set Contrast
+    lcd_write(value_contrast); // (9)  Set Electronic Volume: Set Contrast
+    SPI_PORT |= (1 << LCD_CD);
+}
+
+void lcd_update_backlight(void) {
+    switch (value_backlight) {
+    case 0:
+        DDRD &= (0 << PD5);
+        break;
+    default:
+        DDRD |= (1 << PD5);
+        OCR0B = value_backlight - 1;
+        break;
+    }
+}
+
 void lcd_fill(uint8_t data) {
     for (uint8_t i = 0; i < 8; i++) {
         SPI_PORT &= ~(1 << LCD_CD);
@@ -407,18 +426,19 @@ static void lcd_setup(void) {
         lcd_write_kerning(2, contrast_selected);
         lcd_write_symbol_page(&sym_colon, i, contrast_selected);
         lcd_write_kerning(2, contrast_selected);
-        lcd_write_kerning(9, false);
+        lcd_write_kerning(16, false);
-        lcd_write_integer_page(value_contrast, 3, i, change_contrast_selected);
+        lcd_write_integer_page(value_contrast, 2, i, change_contrast_selected);
         lcd_write_kerning(2, change_contrast_selected);
     }
 
     for (uint8_t i = 0; i < 2; i++) {
         SPI_PORT &= ~(1 << LCD_CD);
-        lcd_write(0x02);
+        lcd_write(0x00);
         lcd_write(0x10);
         lcd_write(0xB4 + i);
         SPI_PORT |= (1 << LCD_CD);
 
+        lcd_write_kerning(2, backlight_selected);
         lcd_write_symbol_page(&sym_b, i, backlight_selected);
         lcd_write_kerning(2, backlight_selected);
         lcd_write_symbol_page(&sym_a, i, backlight_selected);
@@ -517,10 +537,16 @@ static void update_setup(enum input event) {
                 setup_state = contrast;
             break;
         case change_contrast:
+            if (value_contrast < 63) {
                 value_contrast++;
+                lcd_update_contrast();
+            }
             break;
         case change_backlight:
+            if (value_backlight < 100) {
                 value_backlight++;
+                lcd_update_backlight();
+            }
             break;
         }
         lcd_setup();
@@ -535,10 +561,16 @@ static void update_setup(enum input event) {
                 setup_state = back;
             break;
         case change_contrast:
+            if (value_contrast > 0) {
                 value_contrast--;
+                lcd_update_contrast();
+            }
             break;
         case change_backlight:
+            if (value_backlight > 0) {
                 value_backlight--;
+                lcd_update_backlight();
+            }
             break;
         }
         lcd_setup();
@@ -578,11 +610,13 @@ static void update_setup(enum input event) {
         case change_contrast:
             setup_state = contrast;
             value_contrast = eeprom_read_byte(&eeprom_contrast);
+            lcd_update_contrast();
             lcd_setup();
             break;
         case change_backlight:
             setup_state = backlight;
             value_backlight = eeprom_read_byte(&eeprom_backlight);
+            lcd_update_backlight();
             lcd_setup();
             break;
         }
@@ -661,10 +695,9 @@ ISR(PCINT1_vect) {
             TCNT1 = 0;
         }
     } else { // press
-        if (!(TCCR1B & (1 << CS10))) {
+        if (!(TCCR1B & (1 << CS10)))
             TCCR1B |= (1 << CS11) | (1 << CS10); // Enable Timer/Counter1
     }
-    }
 
     // TODO: proper debouncing
     _delay_us(70);
@@ -672,7 +705,7 @@ ISR(PCINT1_vect) {
     sei();
 }
 
-// Timer/Counter1 compare match A
+// Timer/Counter1 compare match A for back event
 ISR(TIMER1_COMPA_vect) {
     cli();
 
@@ -688,13 +721,12 @@ int main(void) {
     value_contrast = eeprom_read_byte(&eeprom_contrast);
     value_backlight = eeprom_read_byte(&eeprom_backlight);
 
-    // FastPWM: 1.25kHz
+    // Init backlight: FastPWM: 1.25kHz
     // TODO: Try to get the backlit even more dim
-    TCCR0A = (1 << WGM01) | (1 << WGM00) | (1 << COM0B1);
+    TCCR0A |= (1 << WGM01) | (1 << WGM00) | (1 << COM0B1);
-    TCCR0B = (1 << CS01) | (1 << WGM02); // prescaler = 8;
+    TCCR0B |= (1 << CS01) | (1 << WGM02); // prescaler = 8;
     OCR0A = 100;
-    OCR0B = 0;
+    lcd_update_backlight();
-    DDRD |= (1 << PD5);
 
     // SPI setup
     spi_init();