keyboards/winkeyless/bface/backlight_ps2avrGB.c

   1 /* Copyright 2017 Sebastian Kaim
   2  *
   3  * This program is free software: you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation, either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15  */
  16
  17 #ifdef BACKLIGHT_ENABLE
  18
  19 #include "backlight_ps2avrGB.h"
  20 #define sbi(reg,bit)    reg |= (_BV(bit))
  21 #define cbi(reg,bit)    reg &= (~_BV(bit))
  22 #define PWM10   WGM10
  23 #define PWM11   WGM11
  24 #define COM1x1 COM1B1
  25 #define OCR1x  OCR1B
  26
  27 void backlight_init_ports(void)
  28 {
  29 #if BACKLIGHT_ON_STATE == 0
  30         backlight_off();
  31 #else
  32         backlight_on();
  33 #endif
  34
  35         // setup pwm
  36         // this bitmagic is sourced from the original firmware
  37         /*TCCR1B = ((TCCR1B & ~0x07) | 0x03);
  38         TCNT1H = 0;
  39         TCNT1L = 0;
  40         sbi(TIMSK, TOIE1);
  41         OCR1BH = 0;
  42         OCR1BL = 0;
  43         cbi(TCCR1A,PWM11);
  44         sbi(TCCR1A,PWM10);
  45         sbi(TCCR1A,COM1B1);
  46         cbi(TCCR1A,COM1B0);*/
  47         ICR1 = 0xFFFF;
  48
  49     TCCR1A = _BV(COM1x1) | _BV(WGM11); // = 0b00001010;
  50     TCCR1B = _BV(WGM13) | _BV(WGM12) | _BV(CS10); // = 0b00011001;
  51
  52         backlight_init();
  53 }
  54
  55 void backlight_set(uint8_t level)
  56 {
  57         if( level == 0 ) {
  58                 backlight_off();
  59         }
  60         else {
  61                 backlight_on();
  62                 /*uint8_t pwm = get_pwm_for_brightness(level);
  63                 set_backlight_pwm(pwm);
  64                 TCCR1A |= _BV(COM1x1);
  65                 OCR1x = (level >= 2) ? 0xFFFF : 0x00FF;*/
  66         }
  67 }
  68
  69 #define PWM_MAX 0xFF
  70 uint8_t get_pwm_for_brightness(uint8_t level)
  71 {
  72         // we need to cast up here to allow multiplication with 0xFF. We could also use floats, but this is probably a lot faster.
  73         uint16_t brightness = (uint16_t)level * (uint16_t)PWM_MAX / (uint16_t)BACKLIGHT_LEVELS;
  74         return (uint8_t)brightness;
  75 }
  76
  77 void backlight_on(void)
  78 {
  79         //_SFR_IO8(0x12) |= _BV(0x4);
  80         LED_PIN |= BACKLIGHT_PORT_NUM;
  81 }
  82
  83 void backlight_off(void)
  84 {
  85         //_SFR_IO8(0x12) &= ~_BV(0x4);
  86         LED_PIN &= ~BACKLIGHT_PORT_NUM;
  87 }
  88
  89 void set_backlight_pwm(uint8_t level) {
  90         // this does not work (yet)
  91         //OCR1B = level;
  92 }
  93
  94 #endif // BACKLIGHT_ENABLE