// Routines to draw pixels in 4096 colors on the Nokia LCD
//  with the Epson S1D15G10 "compatible" controller.
//  by Loren Blaney, 26-Oct-2007
// Based on code by James Lynch.

// Epson S1D15G10 LCD controller command list
#define DISON   0xAF    // Display on
#define DISOFF  0xAE    // Display off
#define DISNOR  0xA6    // Normal display
#define DISINV  0xA7    // Inverse display
#define COMSCN  0xBB    // Common scan direction
#define DISCTL  0xCA    // Display control
#define SLPIN   0x95    // Sleep in
#define SLPOUT  0x94    // Sleep out
#define PASET   0x75    // Page address set
#define CASET   0x15    // Column address set
#define DATCTL  0xBC    // Data scan direction, etc.
#define RGBSET8 0xCE    // 256-color position set
#define RAMWR   0x5C    // Writing to memory
#define RAMRD   0x5D    // Reading from memory
#define PTLIN   0xA8    // Partial display in
#define PTLOUT  0xA9    // Partial display out
#define RMWIN   0xE0    // Read and modify write
#define RMWOUT  0xEE    // End
#define ASCSET  0xAA    // Area scroll set
#define SCSTART 0xAB    // Scroll start set
#define OSCON   0xD1    // Internal oscillation on
#define OSCOFF  0xD2    // Internal oscillation off
#define PWRCTR  0x20    // Power control
#define VOLCTR  0x81    // Electronic volume control
#define VOLUP   0xD6    // Increment electronic control by 1
#define VOLDOWN 0xD7    // Decrement electronic control by 1
#define TMPGRD  0x82    // Temperature gradient set
#define EPCTIN  0xCD    // Control EEPROM
#define EPCOUT  0xCC    // Cancel EEPROM control
#define EPMWR   0xFC    // Write into EEPROM
#define EPMRD   0xFD    // Read from EEPROM
#define EPSRRD1 0x7C    // Read register 1
#define EPSRRD2 0x7D    // Read register 2
#define NOP     0x25    // NOP instruction




void drawPixel(int x, int y, int color) {
// Draw a pixel at the specified coordinates and color
// x     =   column address [0..129]
// y     =   row address [0..129]
// color =   16-bit color value: 0000_RRRR_GGGG_BBBB
    x+=2;               // visible display starts in column 2
    spiCmd(CASET);      // set column address
    spiData(x);         // start
    spiData(x);         // end

    spiCmd(PASET);      // set page (row) address
    spiData(y);         // start
    spiData(y);         // end

    spiCmd(RAMWR);
    spiData(color>>8);  // big endian style
    spiData(color);
} // drawPixel



void fillWin(int area, int color) {     // Fill window with specified color
    int i;
    spiCmd(RAMWR);
    for (i=0; i<area; i++) {
        spiData(color>>8);      // big endian: 0000_RRRR_GGGG_BBBB
        spiData(color);
    }
} // fillWin



int setWin(int x0, int y0, int x1, int y1) {
// Set rectangular area for a window on the LCD
// Returns its area (in pixels)
    int t;

    if (x0>x1) {t=x0; x0=x1; x1=t;}     // put coordinates into ascending order
    if (y0>y1) {t=y0; y0=y1; y1=t;}

    spiCmd(CASET);      // set column address
    spiData(x0+2);      // start (visible area starts in column 2)
    spiData(x1+2);      // end

    spiCmd(PASET);      // set page (row) address
    spiData(y0);        // start
    spiData(y1);        // end

return (x1-x0+1) * (y1-y0+1);   // area
} // setWin



int penX, penY;             // pen coordinates
#define fontHeight 8        // character height in pixels = number of bytes

void chOut(char ch) {       // Draw ASCII character at penX,penY
    int i, j, c, byte;

    setWin(penX, penY, penX+7, penY+fontHeight-1);
    spiCmd(RAMWR);
    ch -= 0x20;                 // table starts with the space character
    for (j=0; j<fontHeight; j++) {
        byte = fontTbl[ch*fontHeight+j];
        for (i=0; i<=7; i++) {  // for each bit in the Byte...
            c = 0;                              // black background
            if (byte & 0x80) c = 0xFFF;         // bright white letters
            spiData(c>>8);
            spiData(c);
            byte = byte << 1;
        }
    }
penX += 8;                  // move to next character position
} //chOut



void initLcd(void) {        // Initialize the Epson S1D15G00 LCD controller
    TRISB = 0xFF13;         //outputs: dat=7 clk=6 spk=5 cs=3 rst=2
    asm volatile ("nop");
    LATB = 0xf00C;          // dat(7)=0 clk(6)=0 spk(5)=0 cs(3)=1 rst(2)=1
    asm volatile ("nop");
    PORTB = 0xf00C;

    RPOR3 = 0x0708;         // set SPI on RB7=SDO1(07); RB6=SCLK1OUT(08)
    SPI1CON1 = 0x013F;
    SPI1CON2 = 0x0000;
    SPI1STAT = 0x8000;

    LCD_RESET = 0;  // reset the controller
    delayMS(10);
    LCD_RESET = 1;
    delayMS(10);
    LCD_CS = 0;     // enable the chip

    spiCmd(DISCTL); // Display control
    spiData(0);     // 2 divisions, switching period=8 (default)
    spiData(32);    // nlines/4 - 1 = 132/4 - 1 = 32)
    spiData(0);     // no inversely highlighted lines

    spiCmd(COMSCN); // Common scan directions
    spiData(1);     // Scan 1->80, 160<-81

    spiCmd(OSCON);  // turn on internal oscillator

    spiCmd(SLPOUT); // Sleep out

    spiCmd(PWRCTR); // Power control
    spiData(0x0F);  // everything on: reference voltage, regulator,
                    //  circuit voltage follower, and boosters
    spiCmd(DISINV); // Inverse display (for proper colors)

    spiCmd(DATCTL); // Data control
    spiData(0x03);  // page address inverted, column address normal,
                    //  address scan in page direction
    spiData(0x00);  // RGB sequence (default)
==> spiData(0x04);  // special mode selects 12-bit color for single pixels <==

    spiCmd(VOLCTR); // Voltage control
    spiData(33);    // contrast setting: 0..63
    spiData(3);     // resistance ratio (only value that works)

    fillWin(setWin(0, 0, 131, 131), 0); // clear display memory

    delayMS(100);   // wait for power supply voltage to stabilize

    spiCmd(DISON);  // turn on the display
} // initLcd