adds backlight levels to the satan keyboard (#431)

[qmk_firmware.git] / keyboard / jd45 / jd45.c

diff --git a/keyboard/jd45/jd45.c b/keyboard/jd45/jd45.c
index bc3fcd3ddfe1131dbde9b6142e143342dfefbb53..5437b2bffc7d0ad97747b7cc63da4c75e3ee3ba4 100644 (file)
--- a/keyboard/jd45/jd45.c
+++ b/keyboard/jd45/jd45.c
@@ -10,18 +10,72 @@ void matrix_scan_user(void) {
 
 };
 
+#define CHANNEL OCR1C
+
+void backlight_init_ports(void)
+{
+
+    // Setup PB7 as output and output low.
+    DDRB |= (1<<7);
+    PORTB &= ~(1<<7);
+    
+    // Use full 16-bit resolution. 
+    ICR1 = 0xFFFF;
+
+    // I could write a wall of text here to explain... but TL;DW
+    // Go read the ATmega32u4 datasheet.
+    // And this: http://blog.saikoled.com/post/43165849837/secret-konami-cheat-code-to-high-resolution-pwm-on
+    
+    // Pin PB7 = OCR1C (Timer 1, Channel C)
+    // Compare Output Mode = Clear on compare match, Channel C = COM1C1=1 COM1C0=0
+    // (i.e. start high, go low when counter matches.)
+    // WGM Mode 14 (Fast PWM) = WGM13=1 WGM12=1 WGM11=1 WGM10=0
+    // Clock Select = clk/1 (no prescaling) = CS12=0 CS11=0 CS10=1
+    
+    TCCR1A = _BV(COM1C1) | _BV(WGM11); // = 0b00001010;
+    TCCR1B = _BV(WGM13) | _BV(WGM12) | _BV(CS10); // = 0b00011001;
+
+    backlight_init();
+}
+
+void backlight_set(uint8_t level)
+{
+    if ( level == 0 )
+    {
+        // Turn off PWM control on PB7, revert to output low.
+        TCCR1A &= ~(_BV(COM1C1));
+        CHANNEL = 0x0;
+        // Prevent backlight blink on lowest level
+        PORTB &= ~(_BV(PORTB7));
+    }
+    else if ( level == BACKLIGHT_LEVELS )
+    {
+        // Prevent backlight blink on lowest level
+        PORTB &= ~(_BV(PORTB7));
+        // Turn on PWM control of PB7
+        TCCR1A |= _BV(COM1C1);
+        // Set the brightness
+        CHANNEL = 0xFFFF;
+    }
+    else        
+    {
+        // Prevent backlight blink on lowest level
+        PORTB &= ~(_BV(PORTB7));
+        // Turn on PWM control of PB7
+        TCCR1A |= _BV(COM1C1);
+        // Set the brightness
+        CHANNEL = 0xFFFF >> ((BACKLIGHT_LEVELS - level) * ((BACKLIGHT_LEVELS + 1) / 2));
+    }
+}
+
 void matrix_init_kb(void) {
        #ifdef BACKLIGHT_ENABLE
        backlight_init_ports();
        #endif
 
-       if (matrix_init_user) {
-               (*matrix_init_user)();
-       }
+       matrix_init_user();
 };
 
 void matrix_scan_kb(void) {
-       if (matrix_scan_user) {
-               (*matrix_scan_user)();
-       }
+       matrix_scan_user();
 };