#90941 by Matthieu Lalonde (mlalonde)

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#include "WProgram.h"

#define DEBUG               1
//#define   USE_SPI             1

// Définition des pins
#define PIN_SYNC            8
#define PIN_VIDEO           9
#define PIN_LED             12
#define PIN_AUDIO           11

#define _SYNC               0x00
#define _BLACK              0x01
#define _GRAY               0x02
#define _WHITE              0x03

// Non modifié, voir mon post!
#define _LONG_SYNC          19
#define _SHORT_SYNC         2
#define _LONG_SYNC_DELAI    2
#define _SHORT_SYNC_DELAI   30

#define _NB_PIXELS          29
#define _NB_LIGNES          19

// Modifié pour NTSC
#define _NB_TV_LIGNES       262

#define _COMPENS_BOUCLE     7
#define _COMPENS_IF_SERIAL  17

#define _BAUD_RATE          19200

// Prototypes
void SPI_MasterInit(void);
void clearScreen(boolean mode);
#ifdef DEBUG
    void blinkStatus(void);
#endif
void resetCursor(void);

// Variables definition
byte memVideo[_NB_PIXELS][_NB_LIGNES];
byte index, index2;

int ligne;
char c;
int cx=(_NB_PIXELS / 2), cy=(_NB_LIGNES / 2);
byte couleur = _BLACK;

#ifdef USE_SPI
void SPI_MasterInit(void)
{
    /* Set MOSI and SCK output, all others input */
    DDRD = (1<<DDB0)|(1<<DDB1);
    /* Enable SPI, Master, set clock rate fck/16 */
    SPCR = (1<<SPE)|(1<<MSTR)|(1<<SPR0);
}
#endif

// Fonction d'effacement de l'écran (avec possibilité de faire un "cadriage" pour les tests)
void clearScreen(boolean mode)
{
    for (index2 = 0; index2 < _NB_LIGNES; index2++)
        for (index = 0; index < _NB_PIXELS; index++)
            if (!mode) {
                memVideo[index][index2] = _BLACK;
            } else {
                memVideo[index][index2] = (index + index2) % 3 + 1;
            }
    
    memVideo[0][0] = _WHITE;
    
    resetCursor();
}

// Remet le curseur au milieux
void resetCursor(void)
{
    cx=(_NB_PIXELS / 2);
    cy=(_NB_LIGNES / 2);
}

#ifdef DEBUG
void blinkStatus(void)
{
    int ii;
    
    pinMode(PIN_LED, OUTPUT);
    
    for(ii=0;ii<3;ii++)
    {
        digitalWrite(PIN_LED, HIGH);
        delay(75);
        digitalWrite(PIN_LED, LOW);
        delay(75);
        digitalWrite(PIN_LED, HIGH);
        if (ii < 2) delay(75);
    }
}
#endif

void setup()
{
    pinMode(PIN_SYNC, OUTPUT);
    pinMode(PIN_VIDEO, OUTPUT);
    pinMode(PIN_AUDIO, OUTPUT);
    
    digitalWrite(PIN_SYNC, HIGH);
    digitalWrite(PIN_VIDEO, HIGH);
    
#ifdef USE_SPI
    SPI_MasterInit();
#endif
    Serial.begin(_BAUD_RATE);
    Serial.println("GO");
    
    clearScreen(true);
#ifdef DEBUG
    blinkStatus();
#endif
}

void loop()
{
    // SYNC VERT A
    
    /**
     * Cette section je suis pas certain de comprendre
    **/
    
    // ligne 1 LONG SYNC
    PORTB = _SYNC; delayMicroseconds(_LONG_SYNC);
    PORTB = _BLACK; delayMicroseconds(_LONG_SYNC_DELAI);

    PORTB = _SYNC; delayMicroseconds(_LONG_SYNC);
    PORTB = _BLACK; delayMicroseconds(_LONG_SYNC_DELAI);

    // ligne 2 LONG SYNC
    PORTB = _SYNC; delayMicroseconds(_LONG_SYNC);
    PORTB = _BLACK; delayMicroseconds(_LONG_SYNC_DELAI);

    PORTB = _SYNC; delayMicroseconds(_LONG_SYNC);
    PORTB = _BLACK; delayMicroseconds(_LONG_SYNC_DELAI);

    // ligne 3 MIXTE SYNC
    PORTB = _SYNC; delayMicroseconds(_LONG_SYNC);
    PORTB = _BLACK; delayMicroseconds(_LONG_SYNC_DELAI);

    PORTB = _SYNC; delayMicroseconds(_SHORT_SYNC);
    PORTB = _BLACK; delayMicroseconds(_SHORT_SYNC_DELAI);

    // ligne 4 SHORT SYNC
    PORTB = _SYNC; delayMicroseconds(_SHORT_SYNC);
    PORTB = _BLACK; delayMicroseconds(_SHORT_SYNC_DELAI);

    PORTB = _SYNC; delayMicroseconds(_SHORT_SYNC);
    PORTB = _BLACK; delayMicroseconds(_SHORT_SYNC_DELAI);

    // ligne 5 SHORT SYNC
    PORTB = _SYNC; delayMicroseconds(_SHORT_SYNC);
    PORTB = _BLACK; delayMicroseconds(_SHORT_SYNC_DELAI);

    PORTB = _SYNC; delayMicroseconds(_SHORT_SYNC);
    PORTB = _BLACK; delayMicroseconds(_SHORT_SYNC_DELAI-_COMPENS_BOUCLE);

    // IMAGE

    for (ligne = 0; ligne < _NB_TV_LIGNES; ligne++)
    {
        //** synchro

        // HSync
        PORTB = _SYNC;
        delayMicroseconds(4.7); // Modifier NTSC

        // Black
        PORTB = _BLACK;
        delayMicroseconds(4.7); // Modifier NTSC
        
        //** image ligne 51.5 uS
        
        for (index = 0; index < _NB_PIXELS; index++)
        {
            PORTB = memVideo[index][ligne>>4];
            PORTB = PORTB;  // Pas sur de comprendre ???
            PORTB = PORTB;  // Pas sur de comprendre ???
        }
        
        delayMicroseconds(1.4); // Modifier NTSC
        
        /**
         * Cette section je suis pas certain de comprendre
        **/
        PORTB = _BLACK;
        PORTB = _BLACK;
        PORTB = _BLACK;
        PORTB = _BLACK;
        PORTB = _BLACK;

        PORTB = _BLACK;
        PORTB = _BLACK;
        PORTB = _BLACK;
        PORTB = _BLACK;
    }

    // SYNC VERT B
    
    /**
     * Cette section je suis pas certain de comprendre
    **/
    
    // ligne 310 LONG SYNC
    PORTB = _SYNC; delayMicroseconds(_SHORT_SYNC);
    PORTB = _BLACK; delayMicroseconds(_SHORT_SYNC_DELAI);

    PORTB = _SYNC; delayMicroseconds(_SHORT_SYNC);
    PORTB = _BLACK; delayMicroseconds(_SHORT_SYNC_DELAI);

    // ligne 311 SHORT SYNC
    PORTB = _SYNC; delayMicroseconds(_SHORT_SYNC);
    PORTB = _BLACK; delayMicroseconds(_SHORT_SYNC_DELAI);

    PORTB = _SYNC; delayMicroseconds(_SHORT_SYNC);
    PORTB = _BLACK; delayMicroseconds(_SHORT_SYNC_DELAI);

    // ligne 312 SHORT SYNC
    PORTB = _SYNC; delayMicroseconds(_SHORT_SYNC);
    PORTB = _BLACK; delayMicroseconds(_SHORT_SYNC_DELAI);

    PORTB = _SYNC; delayMicroseconds(_SHORT_SYNC);
    PORTB = _BLACK; delayMicroseconds(_SHORT_SYNC_DELAI-_COMPENS_BOUCLE-_COMPENS_IF_SERIAL);
    
    if (Serial.available())
    {
        c = Serial.read();
        switch (c)
        {
            case '4' : if (cx>0) cx--; break;
            case '6' : if (cx<29) cx++; break;
            case '8' : if (cy>0) cy--; break;
            case '2' : if (cy<18) cy++; break;
            case '5' : memVideo[cx][cy] = couleur; break;
            case 'n' : couleur = _BLACK; break;
            case 'g' : couleur = _GRAY; break;
            case 'b' : couleur = _WHITE; break;
            case 'c' : clearScreen(false); break;       // Clear screen
            case 'f' : clearScreen(true); break;        // Fill screen
        }
    }
}