From f121a98ae39bc23a5d9cf5533cbcf83c2523a2a0 Mon Sep 17 00:00:00 2001
From: Kai Ryu <kai1103@gmail.com>
Date: Wed, 16 Apr 2014 12:12:15 +0900
Subject: [PATCH] Bug fix and optimization of breathing led

---
 common/breathing_led.c | 25 +++++++++++--------------
 common/keyboard.c      |  4 ++++
 2 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/common/breathing_led.c b/common/breathing_led.c
index d71bf5b8..80bb9d59 100644
--- a/common/breathing_led.c
+++ b/common/breathing_led.c
@@ -6,7 +6,7 @@
 #include "backlight.h"
 #include "debug.h"
 
-#define BREATHING_LED_TIMER_TOP F_CPU/64
+#define BREATHING_LED_TIMER_TOP F_CPU/256
 
 breathing_led_config_t breathing_led_config;
 
@@ -14,9 +14,9 @@ void breathing_led_init(void)
 {
     /* Timer3 setup */
     /* CTC mode */
-    TCCR3B |= _BV(WGM12);
-    /* Clock selelct: clk/1 */
-    TCCR3B |= _BV(CS10);
+    TCCR3B |= _BV(WGM32);
+    /* Clock selelct: clk/8 */
+    TCCR3B |= _BV(CS30);
     /* Set TOP value */
     uint8_t sreg = SREG;
     cli();
@@ -81,22 +81,19 @@ void breathing_led_decrease(void)
 }
 
 /* Breathing LED brighness(PWM On period) table
- * (64[steps] * 4[duration]) / 64[PWM periods/s] = 4 second breath cycle
  *
- * http://www.wolframalpha.com/input/?i=%28sin%28+x%2F64*pi%29**8+*+255%2C+x%3D0+to+63
- * (0..63).each {|x| p ((sin(x/64.0*PI)**8)*255).to_i }
+ * http://www.wolframalpha.com/input/?i=Table%5Bfloor%28%28exp%28sin%28x%2F256*2*pi%2B3%2F2*pi%29%29-1%2Fe%29*%28256%2F%28e-1%2Fe%29%29%29%2C+%7Bx%2C0%2C255%2C1%7D%5D
+ * Table[floor((exp(sin(x/256*2*pi+3/2*pi))-1/e)*(256/(e-1/e))), {x,0,255,1}]
+ * (0..255).each {|x| print ((exp(sin(x/256.0*2*PI+3.0/2*PI))-1/E)*(256/(E-1/E))).to_i, ', ' }
  */
-static const uint8_t breathing_table[64] PROGMEM = {
-0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 4, 6, 10,
-15, 23, 32, 44, 58, 74, 93, 113, 135, 157, 179, 199, 218, 233, 245, 252,
-255, 252, 245, 233, 218, 199, 179, 157, 135, 113, 93, 74, 58, 44, 32, 23,
-15, 10, 6, 4, 2, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+static const uint8_t breathing_table[256] PROGMEM = {
+0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 2, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 8, 8, 9, 10, 11, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 25, 26, 27, 29, 30, 32, 34, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 56, 58, 61, 63, 66, 68, 71, 74, 77, 80, 83, 86, 89, 92, 95, 98, 102, 105, 108, 112, 116, 119, 123, 126, 130, 134, 138, 142, 145, 149, 153, 157, 161, 165, 169, 173, 176, 180, 184, 188, 192, 195, 199, 203, 206, 210, 213, 216, 219, 223, 226, 228, 231, 234, 236, 239, 241, 243, 245, 247, 248, 250, 251, 252, 253, 254, 255, 255, 255, 255, 255, 255, 255, 254, 253, 252, 251, 250, 248, 247, 245, 243, 241, 239, 236, 234, 231, 228, 226, 223, 219, 216, 213, 210, 206, 203, 199, 195, 192, 188, 184, 180, 176, 173, 169, 165, 161, 157, 153, 149, 145, 142, 138, 134, 130, 126, 123, 119, 116, 112, 108, 105, 102, 98, 95, 92, 89, 86, 83, 80, 77, 74, 71, 68, 66, 63, 61, 58, 56, 53, 51, 49, 47, 45, 43, 41, 39, 37, 35, 34, 32, 30, 29, 27, 26, 25, 23, 22, 21, 19, 18, 17, 16, 15, 14, 13, 12, 11, 11, 10, 9, 8, 8, 7, 6, 6, 5, 5, 4, 4, 3, 3, 2, 2, 2, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
 };
 
 ISR(TIMER3_COMPA_vect)
 {
-    uint8_t index = 0;
-    uint8_t step = 0;
+    static uint8_t index = 0;
+    static uint8_t step = 0;
     step++;
     if (step >= BREATHING_LED_LEVELS - breathing_led_config.level) {
         step = 0;
diff --git a/common/keyboard.c b/common/keyboard.c
index 933eb780..29155cfe 100644
--- a/common/keyboard.c
+++ b/common/keyboard.c
@@ -81,6 +81,10 @@ void keyboard_init(void)
     backlight_init();
 #endif
 
+#ifdef BREATHING_LED_ENABLE
+    breathing_led_init();
+#endif
+
 #ifdef KEYMAP_EX_ENABLE
     keymap_ex_init();
 #endif