// FIRMWARE REPLACEMENT FOR CHATPAD's pic16f883
// see attached documents to learn more
// release 0.3.1 from jean : giancarlotodone at yahoo dot it
// for the Open Keyboard Project
// thanks alot to Gidi (who owns an half of my chatpad, call him "sponsor")
// and my sweethart piceta; they helped me handling
// cable knots while reversing and testing.
// Thanks as well to all people who demonstrated interest in this project!

#define CONFIG_BAUDRATE 1
#define CONFIG_SENDMODE 2
#define CONFIG_LIGHTMODE 3
#define CONFIG_LIGHTSTRENGTH 4
#define CONFIG_LIGHTFADEOFFTIME 5
#define CONFIG_REPEAT 6          // not used yet
#define CONFIG_ACCEPTCOMMANDS 7  // not used yet
#define CONFIG_MACROS 8          // not used yet

#define SENDMODE_SERIAL 0
#define SENDMODE_SCAN 1
#define SENDMODE_PS2 2 // not used yet

#define LIGHTMODE_ALWAYSOFF 0
#define LIGHTMODE_ALWAYSON 1
#define LIGHTMODE_FADE 2
#define LIGHTMODE_LASTMODE 2

#define BAUDRATE_300    1
#define BAUDRATE_1200   2
#define BAUDRATE_2400   3
#define BAUDRATE_4800   4
#define BAUDRATE_9600   5
#define BAUDRATE_19200  6
#define BAUDRATE_38400  7
#define BAUDRATE_57600  8
#define BAUDRATE_115200 9


const char scanMap[50] = {      // i could output directly idx,
  8,  9, 10, 40, 20, 30, 47,    // but maybe a translation map
 41, 42, 43, 39, 44, 38, 45,    // can prove useful in future.
 31, 32, 33, 35, 34, 36, 37,    // starts from 1...think 0
 21, 22, 23, 25, 24, 26, 27,    // should be reserved for
 11, 12, 13, 15, 14, 16, 17,    // future use
  1,  2,  3,  5,  4,  6,  7,
 28, 18, 19,  0,  0, 29, 46 };

const char serialMap[4][49] = { // CHARACTER MAPPING MATRIX for "pure serial mode"
// normal char press
{56,  57,  48,  13, 112,  44,   0,
  0,   0,   0,  46,  32, 109,   0,
  0, 121, 120, 118,  99,  98, 110,
 97, 115, 100, 103, 102, 104, 106,
113, 119, 101, 116, 114, 122, 117,
 49,  50,  51,  53,  52,  54,  55,
107, 105, 111,   0,   0, 108,   8},

// shifted
{56,  57,  48,  13,  80,  44,   0,
  0,   0,   0,  46,  32,  77,   0,
  0,  89,  88,  86,  67,  66,  78,
 65,  83,  68,  71,  70,  72,  74,
 81,  87,  69,  84,  82,  90,  85,
 49,  50,  51,  53,  52,  54,  55,
 75,  73,  79,   0,   0,  76,   8},

// green alt
{56,  57,  48,  13,  61,  39,   0,
  0,   0,   0,  63,  32,  58,   0,
  0,  60,  62,  45, 126,  42,  59,
  0,   0,   0,   0,   0, 123, 125,
 33,  34, 128,  37,  36,  38,  47,
 49,  50,  51,  53,  52,  54,  55,
 91,  40,  41,   0,   0,  93,   8},

// red alt
{56,  57,  48,  13,  92,  35,   0,
  0,   0,   0,   0,  32,   0,   0,
  0,   0, 124,  95,   0,  43,   0,
  0,   0,   0,   0,   0,  96,   0,
 64,   0,   0,   0,   0,  94,   0,
 49,  50,  51,  53,  52,  54,  55,
  0,   0,   0,   0,   0,   0,   8}
};  ////////// END OF MAPPING MATRIX

  unsigned char data[7] = {0,0,0,0,0,0,0};
  unsigned char oldData[7] = {0,0,0,0,0,0,0};
  unsigned char justPressed[7] = {0,0,0,0,0,0,0};

  unsigned char newlyPressd = 0;

  unsigned char AMask = 0;
  unsigned char BMask = 0;

  unsigned char somethingChanged = 0;

  unsigned long int timer = 0xFFFF;
  unsigned long int lightFadeOffTime = 0x8000;

  // alternates (shift,green,red) mapping to translation map
                        // 0  1  2  3  4  5  6  7
  unsigned char alts [] = {0, 1, 2, 2, 3, 3, 3, 3};
  unsigned char alt;

  void (*send)() = 0;
  void (*lightHandler)() = 0;

  unsigned char baudrate = 0;
  unsigned char sendMode = 0;
  unsigned char lightMode = 0;
  unsigned char lightStrenght = 0;

  unsigned char pwmRunning = 0;
  
  void enterPowerSave(){
    PORTA = 0;
    INTCON.RBIE = 1; // enables PORTB on-change interrupt
    asm{
        sleep;
    }
  }

  void exitPowerSave(){
     INTCON.RBIE = 0; // disables PORTB on-change interrupt
  }

  void setupUsart(unsigned char br){
    switch(br){  // done so, because you can't call USART_Init(variable); but only USART_Init(literal);
       case BAUDRATE_300:    USART_Init(300);
          break;
       case BAUDRATE_1200:   USART_Init(1200);
          break;
       case BAUDRATE_2400:   USART_Init(2400);
          break;
       case BAUDRATE_4800:   USART_Init(4800);
          break;
       case BAUDRATE_9600:   USART_Init(9600);
          break;
       case BAUDRATE_19200:  USART_Init(19200);
          break;
       case BAUDRATE_38400:  USART_Init(38400);
          break;
       case BAUDRATE_57600:  USART_Init(57600);
          break;
       case BAUDRATE_115200: USART_Init(115200);
          break;
       default: EEprom_write(CONFIG_BAUDRATE, BAUDRATE_4800); // if no config found, set a default 4800
                br = BAUDRATE_4800;
                USART_Init(4800);
    }
    baudrate = br;
  }

  void turnBacklightOn(){
       timer = lightFadeOffTime;
       if (!pwmRunning) {
          PWM1_Start();
          PWM2_Start();
          pwmRunning = 1;
       }
       PWM1_Change_Duty(lightStrenght);
       PWM2_Change_Duty(lightStrenght);
  }

  void nop(){

  }

  void lightFade(){
       unsigned char s;
       if (newlyPressd) {
          turnBacklightOn();
          return;
       }

       if (timer>0) timer --;
       else {
            PWM1_Stop;
            PWM2_Stop;
            PORTC = 255;
            pwmRunning = 0;
            enterPowerSave();
       }

       if (timer<(~lightStrenght)){
          PWM1_Change_Duty(~((unsigned char)timer));
          PWM2_Change_Duty(~((unsigned char)timer));
       }

  }

  void setupLightMode(unsigned char lm){

    if (pwmRunning){
       PWM1_Stop();
       PWM2_Stop();
    }
    
    switch (lm){
       case LIGHTMODE_ALWAYSOFF: lightHandler = &nop;
                                 lightStrenght = 0xFF;
                                 lightMode = LIGHTMODE_ALWAYSOFF;
                                 break;
                                 
       case LIGHTMODE_ALWAYSON:  lightHandler = &nop;
                                 turnBacklightOn();
                                 lightMode = LIGHTMODE_ALWAYSON;
                                 break;

       case LIGHTMODE_FADE:      lightHandler = &lightFade;
                                 turnBacklightOn();
                                 lightStrenght = 0x80;   // restore middle luminosity
                                 lightMode = LIGHTMODE_FADE;
                                 break;
                                 
       default                 : EEprom_write(CONFIG_LIGHTMODE, LIGHTMODE_ALWAYSOFF);
                                 lightMode = LIGHTMODE_ALWAYSOFF;
                                 lightHandler = &nop;
                                 lightStrenght = 0xFF;
    }

    PORTC = 255;

    // PWM init
    if (lightMode != LIGHTMODE_ALWAYSOFF) {
      PWM1_Init(40000);
      PWM1_Change_Duty(lightStrenght);
      PWM1_Start();

      PWM2_Init(40000);
      PWM2_Change_Duty(lightStrenght);
      PWM2_Start();
      
      pwmRunning = 1;
    }
  }

  void doScan(){
    unsigned char sc = 0;

    newlyPressd = 0;
    
    for (AMask=1; AMask<128; AMask<<=1){

       oldData[sc] = data[sc]; // save old data

       PORTA = ~AMask; // put a 0 on the line we want to inspect
       data[sc] = PORTB;  // read PORTB (pulled up)...if a line goes to 0, bingo!
       data[sc] = data[sc] | PORTB; // antibounce
       data[sc] = data[sc] | PORTB; // antibounce
       data[sc] = ~data[sc]; // return to positive logic

       justPressed[sc] = data[sc]&(~oldData[sc]);

       newlyPressd = newlyPressd | justPressed[sc];
       
       sc++;
    }
  }

  
  void serialSend(){
    unsigned char idx = 0;
    unsigned char sc = 0;

    for (AMask=1; AMask<128; AMask<<=1){
      for (BMask=1; BMask<128; BMask<<=1){
        if (justPressed[sc] & BMask) USART_Write(serialMap[alt][idx]);
        idx++;
      }
      sc++;
    }
    alt = alts[data[2]&1|((data[1]&1)<<1)|((data[0]&64)>>4)]; // next scan can use alt retrieved here
  }
  
  void scanSend(){
    unsigned char idx = 0;
    unsigned char sc = 0;
    unsigned char bs = 0;

    for (AMask=1; AMask<128; AMask<<=1){
      somethingChanged = data[sc] ^ oldData[sc];
      bs = 0;
      for (BMask=1; BMask<128; BMask<<=1){
        if (someThingChanged & BMask)
           USART_Write(scanMap[idx] | (((data[sc]&BMask)>>bs)<<6)); // | 64 if pressed
        bs++;
        idx++;
      }
      sc++;
    }
  }
  
  void ps2Send(){
       // not implemented yet
  }
  
  void setupSendMode(unsigned char sm){
       switch (sm){
         case SENDMODE_SCAN  : send = &scanSend;
                               sendMode = SENDMODE_SCAN;
                               break;

         case SENDMODE_SERIAL: send = &serialSend;
                               sendMode = SENDMODE_SERIAL;
                               break;

//		 case SENDMODE_PS2:	   send = &ps2send;
//							             sendMode = SENDMODE_PS2;
//                             break;

         default             : send = &serialSend;
                               EEprom_write(CONFIG_SENDMODE, SENDMODE_SERIAL);
                               sendMode = SENDMODE_SERIAL;
       }
  }
  
  void config(){
       timer = lightFadeOffTime;

       if ((data[1]&4)&&(lightStrenght<0xff)) {   // <
          lightStrenght++;
          PWM1_Change_Duty(lightStrenght);
          PWM2_Change_Duty(lightStrenght);
          if (lightMode==LIGHTMODE_ALWAYSOFF) lightMode = LIGHTMODE_FADE;
       }  // decrease light strenght
       
       if ((data[1]&64)&&(lightStrenght>0)) {   // >
          lightStrenght--;
          PWM1_Change_Duty(lightStrenght);
          PWM2_Change_Duty(lightStrenght);
          if (lightMode==LIGHTMODE_ALWAYSOFF) lightMode = LIGHTMODE_FADE;
       } // increase light strenght

       
       if (justPressed[5]&1){ // 1
//          if (data[1]&1)              // this buttion combination just doesn't work...think that's because of the buttons staying on the same matrix line.
//             setupUsart(BAUDRATE_4800);
//          else {
               setupLightMode(LIGHTMODE_FADE);
               lightFadeOffTime = 2<<8;
//          }
       }

       if (justPressed[5]&2){ // 2
          if (data[1]&1)
             ;//setupUsart(BAUDRATE_300);     //all setupUsart commented out are to save code words space...otherwise i'm running into demo limit
          else {                              //consider donating some money to me to purchase a full version of mikroC and continue development
               setupLightMode(LIGHTMODE_FADE);
               lightFadeOffTime = 4<<8;  // more or less 5 sec
          }
       }

       if (justPressed[5]&4){ // 3
          if (data[1]&1)
             ;//setupUsart(BAUDRATE_1200);
          else {
               setupLightMode(LIGHTMODE_FADE);
               lightFadeOffTime = 8<<8;
          }
       }

       if (justPressed[5]&16){ // 4
          if (data[1]&1)
             ;//setupUsart(BAUDRATE_2400);
          else {
               setupLightMode(LIGHTMODE_FADE);
               lightFadeOffTime = 16<<8;
          }
       }

       if (justPressed[5]&8){ // 5
          if (data[1]&1)
             setupUsart(BAUDRATE_4800);
          else {
               setupLightMode(LIGHTMODE_FADE);
               lightFadeOffTime = 32<<8;
          }
       }

       if (justPressed[5]&32){ // 6
          if (data[1]&1)
             setupUsart(BAUDRATE_9600);
          else {
               setupLightMode(LIGHTMODE_FADE);
               lightFadeOffTime = 64<<8;
          }
       }

       if (justPressed[5]&64){ // 7
          if (data[1]&1)
             ;//setupUsart(BAUDRATE_19200);
          else {
               setupLightMode(LIGHTMODE_FADE);
               lightFadeOffTime = 128<<8;
          }
       }

       if (justPressed[0]&1){ // 8
          if (data[1]&1)
             ;//setupUsart(BAUDRATE_38400);
          else {
               setupLightMode(LIGHTMODE_FADE);
               lightFadeOffTime = 255<<8;
          }
       }

       if (justPressed[0]&2){ // 9
          if (data[1]&1)
             ;//setupUsart(BAUDRATE_57600);
          else
             setupLightMode(LIGHTMODE_ALWAYSON);
       }

       if (justPressed[0]&4){ // 0
          if (data[1]&1)
             ;//setupUsart(BAUDRATE_115200);
          else
              setupLightMode(LIGHTMODE_ALWAYSOFF);
       }

       if (justPressed[3]&1){ // A
          setupSendMode(SENDMODE_SCAN);
       }

       if (justPressed[3]&2){ // S
          setupSendMode(SENDMODE_SERIAL);
       }

       Delay_5ms();

  }
  
  void saveConfig(){
       EEprom_write(CONFIG_BAUDRATE, baudrate);
       EEprom_write(CONFIG_SENDMODE, sendMode);
       EEprom_write(CONFIG_LIGHTMODE, lightMode);
       EEprom_write(CONFIG_LIGHTSTRENGTH, lightStrenght);
       EEprom_write(CONFIG_LIGHTFADEOFFTIME, lightFadeOffTime>>8);
  }
  
  void interrupt() {
     if (INTCON.RBIF) { // SOMETHING CHANGED ON PORTB...
        exitPowerSave(); // just wakeup and so some scanning...
        INTCON.RBIF = 0; // clear intr flag
     }

//     if (PIR1.RCIF) { // USART RECEIVE BUFFER () FULL...
//
//     }
  }

void main() {

  OSCCON = 0x67;                    // 01100111 - 0110 stands for 4Mhz internal clock

  ANSEL  = 0;                       // Configure AN pins as digital I/O
  ANSELH = 0;
  
  PORTA  = 0;                       // init port A
  TRISA  = 0;                       // 1 = input
  
  PORTB       = 0;                  // initialize PORTB
  TRISB       = 255;                // designate PORTB as all input
  
  PORTC       = 0;                // initialize PORTC
  TRISC       = 0;                // designate PORTB 0-7 as output

  OPTION_REG  = 0;                  // pull-ups enabled on PORTB....no external pull-downs
                                    // present, so we have to run negative logic...
                                    
  //WPUB = 127; // weak pull-ups enabled on PORTB 0-6 // AAARGH!! this caused random Light-On

  INTCON.RBIE = 0; // disables PORTB on-change interrupt
  INTCON.RBIF = 0; // clear PORTB mismatch values

  IOCB = 127; // pin 0-6 of PORTB configured to raise interrupt when changed
  
  PIE1 = 32; // RCIE = 1; enables EUSART on-receive interrupt
    
  INTCON.GIE = 1; // Global Interrupt Enable/disable

   // SEND MODE ------------------
  Delay_ms(20);    // required for eeprom_read to work correctly
  sendMode = EEprom_read(CONFIG_SENDMODE);
  setupSendMode(sendMode);
  // TODO: if in PS2 mode don't initialize usart
  
  // USART ---------------
  Delay_ms(20);    // required for eeprom_read to work correctly
  baudrate = EEprom_read(CONFIG_BAUDRATE);
  setupUsart(baudrate); // Initalize USART (xxxx baud rate, 1 stop bit, no parity...)

   // LIGHTS ----------------
  Delay_ms(20);    // required for eeprom_read to work correctly
  lightFadeOffTime = EEprom_read(CONFIG_LIGHTFADEOFFTIME) << 8;
  lightStrenght = EEprom_read(CONFIG_LIGHTSTRENGTH);

  Delay_ms(20);    // required for eeprom_read to work correctly
  lightMode = EEprom_read(CONFIG_LIGHTMODE);
  setUpLightMode(lightMode);

  do {

    doScan();

    if (data[1]&2) {
       config();  // people button pressed -> config mode
    }else{
       if (oldData[1]&2) saveConfig(); // ppl btn just released... save config
       send();
    }
    lightHandler();
    Delay_80us(); // without this delay, pic hangs on sleep...
  } while (1);                   // endless loop

}