/*

  Fernbedienung für Dunstabzugshaube
  Emulation der originalen Fernbedienung von Siemens 12026292

*/

#define F_CPU 9600000       // Hz

#include "avr/io.h"
#include "avr/interrupt.h"
#include "avr/sleep.h"
#include "avr/pgmspace.h"
#include "util/delay.h"

#define F_CARRIER 38000     // Hz
#define CARRIER_PERIOD (F_CPU/(2*F_CARRIER))    // Trägerfrequenz für IR
#define PULSE_WIDTH (CARRIER_PERIOD/3)          // Tastverhältnis ca. 33%

#if CARRIER_PERIOD > 255
#error F_CPU zu hoch, Prescaler benutzen
#endif

#define LED_ON  PORTB  |=  (1<<PB0);
#define LED_OFF PORTB  &= ~(1<<PB0);
#define LED_TOG PORTB  ^=  (1<<PB0);

#define KEY_PIN         PINB
#define KEY0            2
#define KEY1            3

typedef enum{cmd_Power, cmd_Automatic, cmd_Level_inc, cmd_Level_dec, cmd_Light,
             cmd_Light_dec, cmd_Light_inc, cmd_Timer, cmd_Karo} cmd_t;

volatile uint8_t cnt_cmd, cnt_pulse;
volatile uint8_t flag_tx, flag_timer;
volatile PGM_P ir_data;
volatile uint8_t key_state;     // entprellter Tastenzustand: bit = 1: Taste gedrückt
volatile uint8_t key_press;     // Flanke erkannt

/*
 IR Kommandos für Fernbedienung Siemens 12026292 
 
 1. Byte: Anzahl der Pulse
    erster Puls ist immer aktiv, Licht ein
    letzter Puls immer inaktiv, Licht aus
 2-(N-1)Bytes: Pulsbreite in Anzahl Trägerperioden, wechselnde Polarität
*/

const uint8_t cmds[9][31] PROGMEM = {

    {30, 14,  9, 15, 21, 26, 10, 14, 10, 13, 11, 14,  9, 15, 21, 27,
     21, 14, 10, 13, 11, 13, 11, 14,  9, 15,  9, 15,  9, 26,  1},
    {30, 14, 10, 14, 22, 25, 11, 13, 11, 13, 11, 13, 10, 14, 22, 25,
     22, 14, 10, 14, 10, 14, 10, 14, 10, 14, 10, 25, 22, 13,  1},
    {30, 14, 10, 13, 22, 25, 11, 13, 10, 14, 10, 14, 10, 14, 22, 25,
     22, 14, 10, 14, 10, 14, 10, 14, 10, 13, 11, 25, 10, 14,  1},
    {30, 14,  9, 14, 22, 25, 10, 14, 10, 14, 10, 14, 10, 14, 22, 26,
     22, 14, 10, 14, 10, 14, 10, 14, 10, 25, 22, 14, 10, 14,  1},
    {28, 14, 10, 14, 22, 25, 11, 14,  9, 14, 11, 13, 11, 13, 22, 27,
     21, 13, 11, 13, 11, 13, 10, 14, 10, 25, 22, 25,  1,  0,  0},
    {30, 13, 11, 13, 22, 25, 11, 13, 10, 14, 10, 14, 10, 14, 22, 25,
     22, 14, 10, 14, 10, 14, 10, 14, 10, 25, 10, 14, 10, 14,  1},
    {30, 14, 10, 14, 22, 27,  9, 15,  9, 15,  9, 15,  9, 14, 22, 25,
     22, 15,  9, 15,  9, 15,  9, 15,  9, 26, 10, 14, 22, 14,  1},
    {30, 14, 10, 14, 22, 25, 11, 13, 11, 14,  9, 14, 11, 13, 22, 25,
     22, 13, 11, 13, 11, 13, 11, 25, 22, 14, 10, 14, 10, 14,  1},
    {38, 14,  9, 14, 22, 25, 11, 13, 11, 13, 10, 15,  9, 14, 22, 25,
     22, 13, 11, 13, 10, 14, 10, 25, 22, 25, 22, 13,  1,  0,  0}
};

void send_cmd(cmd_t cmd) {

    PGM_P data = (char*)cmds[cmd];
    cnt_cmd    = pgm_read_byte(data++);
    cnt_pulse  = pgm_read_byte(data);
    ir_data    = data;
    TCCR0B     = (1<<WGM02) | (1<<CS00);    // Prescaler 1 für IR codes
    flag_timer = 0;
    while(!flag_timer);
    //LED_ON
    OCR0B = PULSE_WIDTH;
    flag_tx = 1;
    while(flag_tx) {
        set_sleep_mode(SLEEP_MODE_IDLE);
        sleep_mode();
    }
    TCCR0B = (1<<WGM02) | (1<<CS02) | (1<<CS00);    // Prescaler 1024 für Wartebetrieb, ~25ms (40Hz)
    //LED_OFF
}

void send_cmd_multi(cmd_t cmd, uint8_t cnt) {
    uint8_t j;

    for(; cnt>0; cnt--) {
        send_cmd(cmd);
        for(j=0; j<4; j++) {
            set_sleep_mode(SLEEP_MODE_IDLE);
            sleep_mode();
        }        
    } 
}

void sequence_Power_Automatic(void) {

    send_cmd_multi(cmd_Power, 3);
    send_cmd_multi(cmd_Automatic,3);
}

void sequence_Light(void) {
    send_cmd_multi(cmd_Light, 3);
}

uint8_t get_key_press( uint8_t key_mask ) {
  cli();                                          // read and clear atomic !
  key_mask &= key_press;                          // read key(s)
  key_press ^= key_mask;                          // clear key(s)
  sei();
  return key_mask;
}

int main(void) {

    // IOs initialisieren
    DDRB  = (1<<PB1) | (1<<PB0);
    PORTB = (1<<PB4) | (1<<PB3) | (1<<PB2);

    // Timer 0 initialisieren
    // mode 5, phase correct PWM, prescaler 1024
    TCCR0A = (1<<COM0B1) | (1<<WGM00);
    TCCR0B = (1<<WGM02) | (1<<CS02) | (1<<CS00);    // Prescaler 1024 für Wartebetrieb, ~25ms (40Hz)
//    TCCR0B = (1<<WGM02) | (1<<CS00);    // TEST, prescaler 1
    OCR0A = CARRIER_PERIOD;
    OCR0B = CARRIER_PERIOD/2;
    TIMSK0 = (1<<OCIE0A);   // Interrupt freigeben
    
    OSCCAL = 0x4F;
    sei();
    send_cmd(cmd_Light_dec);        // Workaround für hohe Stromaufnahme nach Reset ???

    while(1) {
        set_sleep_mode(SLEEP_MODE_IDLE);
        sleep_mode();
        //LED_TOG
        if (get_key_press(1<<KEY0)) {
            LED_ON
            sequence_Power_Automatic();
            LED_OFF
        }
        if (get_key_press(1<<KEY1)) {
            LED_ON
            sequence_Light();
            LED_OFF
        }
    }

    return 0;
}

// TIMER 0 ISR, Trägerfrequenz

ISR(TIM0_COMPA_vect) {
    static uint8_t ct0 = 0xFF, ct1 = 0xFF;
    uint8_t i;


    if (flag_tx) {      // IR Code senden
        cnt_pulse--;
        if (cnt_pulse == 0) {
            cnt_cmd--;
            if (cnt_cmd != 0) {
                ir_data++;
                cnt_pulse = pgm_read_byte(ir_data);
                if (OCR0B == 0) {
                    OCR0B = PULSE_WIDTH;
                } else {
                    OCR0B = 0;
                }
            } else {
                OCR0B = 0;
                flag_tx = 0;
            }
        }
    } else {        // nur langsamer Timer für Tastenüberwachung
        flag_timer = 1;
        
        // Tastenentprellung 
        i = key_state ^ ~KEY_PIN;                       // key changed ?
        ct0 = ~( ct0 & i );                             // reset or count ct0
        ct1 = ct0 ^ (ct1 & i);                          // reset or count ct1
        i &= ct0 & ct1;                                 // count until roll over ?
        key_state ^= i;                                 // then toggle debounced state
        key_press |= key_state & i;                     // 0->1: key press detect
    }
}