/* Display a text message on the TFT with ILI9340
 *
 * This program initializes the ILI9340 controller of a QVGA TFT
 * display then shows a text message.
 *
 */

#include "stm32f4xx.h"

#define TFTWIDTH    240
#define TFTHEIGHT   320
// Color definitions
#define BLACK   0x0000
#define BLUE    0x001F
#define RED     0xF800
#define GREEN   0x07E0
#define CYAN    0x07FF
#define MAGENTA 0xF81F
#define YELLOW  0xFFE0
#define WHITE   0xFFFF

// font table
const uint8_t font5x7[][6]=
{
   {0x00, 0x00, 0x00, 0x00, 0x00} // 20
  ,{0x00, 0x00, 0xBE, 0x00, 0x00} // 21 !
  ,{0x00, 0x0E, 0x00, 0x0E, 0x00} // 22 "
  ,{0x28, 0xFE, 0x28, 0xFE, 0x28} // 23 #
  ,{0x48, 0x54, 0xFE, 0x54, 0x24} // 24 $
  ,{0x46, 0x26, 0x10, 0xC8, 0xC4} // 25 %
  ,{0x6C, 0x92, 0xAA, 0x44, 0xA0} // 26 &
  ,{0x00, 0x0A, 0x06, 0x00, 0x00} // 27 '
  ,{0x00, 0x38, 0x44, 0x82, 0x00} // 28 (
  ,{0x00, 0x82, 0x44, 0x38, 0x00} // 29 )
  ,{0x28, 0x10, 0x7C, 0x10, 0x28} // 2a *
  ,{0x10, 0x10, 0x7C, 0x10, 0x10} // 2b +
  ,{0x00, 0xA0, 0x60, 0x00, 0x00} // 2c
  ,{0x10, 0x10, 0x10, 0x10, 0x10} // 2d -
  ,{0x00, 0xC0, 0xC0, 0x00, 0x00} // 2e .
  ,{0x40, 0x20, 0x10, 0x08, 0x04} // 2f /
  ,{0x7C, 0xA2, 0x92, 0x8A, 0x7C} // 30 0
  ,{0x00, 0x84, 0xFE, 0x80, 0x00} // 31 1
  ,{0x84, 0xC2, 0xA2, 0x92, 0x8C} // 32 2
  ,{0x42, 0x82, 0x8A, 0x96, 0x62} // 33 3
  ,{0x30, 0x28, 0x24, 0xFE, 0x20} // 34 4
  ,{0x4E, 0x8A, 0x8A, 0x8A, 0x72} // 35 5
  ,{0x78, 0x94, 0x92, 0x92, 0x60} // 36 6
  ,{0x02, 0xE2, 0x12, 0x0A, 0x06} // 37 7
  ,{0x6C, 0x92, 0x92, 0x92, 0x6C} // 38 8
  ,{0x0C, 0x92, 0x92, 0x52, 0x3C} // 39 9
  ,{0x00, 0x6C, 0x6C, 0x00, 0x00} // 3a :
  ,{0x00, 0xAC, 0x6C, 0x00, 0x00} // 3b ;
  ,{0x10, 0x28, 0x44, 0x82, 0x00} // 3c <
  ,{0x28, 0x28, 0x28, 0x28, 0x28} // 3d =
  ,{0x00, 0x82, 0x44, 0x28, 0x10} // 3e >
  ,{0x04, 0x02, 0xA2, 0x12, 0x0C} // 3f ?
  ,{0x64, 0x92, 0xF2, 0x82, 0x7C} // 40 @
  ,{0xFC, 0x22, 0x22, 0x22, 0xFC} // 41 A
  ,{0xFE, 0x92, 0x92, 0x92, 0x6C} // 42 B
  ,{0x7C, 0x82, 0x82, 0x82, 0x44} // 43 C
  ,{0xFE, 0x82, 0x82, 0x44, 0x38} // 44 D
  ,{0xFE, 0x92, 0x92, 0x92, 0x82} // 45 E
  ,{0xFE, 0x12, 0x12, 0x12, 0x02} // 46 F
  ,{0x7C, 0x82, 0x92, 0x92, 0xF4} // 47 G
  ,{0xFE, 0x10, 0x10, 0x10, 0xFE} // 48 H
  ,{0x00, 0x82, 0xFE, 0x82, 0x00} // 49 I
  ,{0x40, 0x80, 0x82, 0x7E, 0x02} // 4a J
  ,{0xFE, 0x10, 0x28, 0x44, 0x82} // 4b K
  ,{0xFE, 0x80, 0x80, 0x80, 0x80} // 4c L
  ,{0xFE, 0x04, 0x18, 0x04, 0xFE} // 4d M
  ,{0xFE, 0x08, 0x10, 0x20, 0xFE} // 4e N
  ,{0x7C, 0x82, 0x82, 0x82, 0x7C} // 4f O
  ,{0xFE, 0x12, 0x12, 0x12, 0x0C} // 50 P
  ,{0x7C, 0x82, 0xA2, 0x42, 0xBC} // 51 Q
  ,{0xFE, 0x12, 0x32, 0x52, 0x8C} // 52 R
  ,{0x8C, 0x92, 0x92, 0x92, 0x62} // 53 S
  ,{0x02, 0x02, 0xFE, 0x02, 0x02} // 54 T
  ,{0x7E, 0x80, 0x80, 0x80, 0x7E} // 55 U
  ,{0x3E, 0x40, 0x80, 0x40, 0x3E} // 56 V
  ,{0x7E, 0x80, 0x70, 0x80, 0x7E} // 57 W
  ,{0xC6, 0x28, 0x10, 0x28, 0xC6} // 58 X
  ,{0x0E, 0x10, 0xE0, 0x10, 0x0E} // 59 Y
  ,{0xC2, 0xA2, 0x92, 0x8A, 0x86} // 5a Z
  ,{0x00, 0xFE, 0x82, 0x82, 0x00} // 5b [
  ,{0x04, 0x08, 0x10, 0x20, 0x40} // 5c '\'
  ,{0x00, 0x82, 0x82, 0xFE, 0x00} // 5d ]
  ,{0x08, 0x04, 0x02, 0x04, 0x08} // 5e ^
  ,{0x80, 0x80, 0x80, 0x80, 0x80} // 5f _
  ,{0x00, 0x02, 0x04, 0x08, 0x00} // 60 `
  ,{0x40, 0xA8, 0xA8, 0xA8, 0xF0} // 61 a
  ,{0xFE, 0x90, 0x88, 0x88, 0x70} // 62 b
  ,{0x70, 0x88, 0x88, 0x88, 0x40} // 63 c
  ,{0x70, 0x88, 0x88, 0x90, 0xFE} // 64 d
  ,{0x70, 0xA8, 0xA8, 0xA8, 0x30} // 65 e
  ,{0x10, 0xFC, 0x12, 0x02, 0x04} // 66 f
  ,{0x18, 0xA4, 0xA4, 0xA4, 0x7C} // 67 g
  ,{0xFE, 0x10, 0x08, 0x08, 0xF0} // 68 h
  ,{0x00, 0x88, 0xFA, 0x80, 0x00} // 69 i
  ,{0x40, 0x80, 0x88, 0x7A, 0x00} // 6a j
  ,{0xFE, 0x20, 0x50, 0x88, 0x00} // 6b k
  ,{0x00, 0x82, 0xFE, 0x80, 0x00} // 6c l
  ,{0xF8, 0x08, 0x30, 0x08, 0xF0} // 6d m
  ,{0xF8, 0x10, 0x08, 0x08, 0xF0} // 6e n
  ,{0x70, 0x88, 0x88, 0x88, 0x70} // 6f o
  ,{0xF8, 0x28, 0x28, 0x28, 0x10} // 70 p
  ,{0x10, 0x28, 0x28, 0x30, 0xF8} // 71 q
  ,{0xF8, 0x10, 0x08, 0x08, 0x10} // 72 r
  ,{0x90, 0xA8, 0xA8, 0xA8, 0x40} // 73 s
  ,{0x08, 0x7E, 0x88, 0x80, 0x40} // 74 t
  ,{0x78, 0x80, 0x80, 0x40, 0xF8} // 75 u
  ,{0x38, 0x40, 0x80, 0x40, 0x38} // 76 v
  ,{0x78, 0x80, 0x60, 0x80, 0x78} // 77 w
  ,{0x88, 0x50, 0x20, 0x50, 0x88} // 78 x
  ,{0x18, 0xA0, 0xA0, 0xA0, 0x78} // 79 y
  ,{0x88, 0xC8, 0xA8, 0x98, 0x88} // 7a z
  ,{0x00, 0x10, 0x6C, 0x82, 0x00} // 7b {
  ,{0x00, 0x00, 0xFE, 0x00, 0x00} // 7c |
  ,{0x00, 0x82, 0x6C, 0x10, 0x00} // 7d }
  ,{0x20, 0x10, 0x10, 0x20, 0x10} // 7e ~
  ,{0x00, 0x1C, 0x14, 0x1C, 0x00} // 7f degree
};
#define FONTWIDTH 6
#define FONTHEIGHT 8

#define ILI9340_SLPOUT  0x11
#define ILI9340_GAMMASET 0x26
#define ILI9340_DISPON  0x29
#define ILI9340_CASET   0x2A
#define ILI9340_PASET   0x2B
#define ILI9340_RAMWR   0x2C
#define ILI9340_MADCTL  0x36
#define ILI9340_MADCTL_MX  0x40
#define ILI9340_MADCTL_BGR 0x08
#define ILI9340_PIXFMT  0x3A
#define ILI9340_FRMCTR1 0xB1
#define ILI9340_DFUNCTR 0xB6
#define ILI9340_PWCTR1  0xC0
#define ILI9340_PWCTR2  0xC1
#define ILI9340_VMCTR1  0xC5
#define ILI9340_VMCTR2  0xC7
#define ILI9340_GMCTRP1 0xE0
#define ILI9340_GMCTRN1 0xE1

#define ILI9340_setCommand()    GPIOA->BSRR = 0x08000000;   /* make DC PA11 low */
#define ILI9340_setData()       GPIOA->BSRR = 0x00000800;   /* make DC PA11 high */
#define ILI9340_assertSS()      GPIOC->BSRR = 0x00020000;   /* assert   /SS PC1 */
#define ILI9340_deassertSS()    GPIOC->BSRR = 0x00000002;   /* deassert /SS PC1 */
#define ILI9340_reset()         ;  /* make RESET P2.6 low */
#define ILI9340_dereset()       ;     /* make RESET P2.6 high */

void SPI_init(void);
void SPI_write(unsigned char data);
void ILI9340_hardReset(void);
void ILI9340_command(uint8_t command);
void ILI9340_data(uint8_t data);
void ILI9340_blockData(int32_t n, uint16_t color);
void delayMs(int32_t n);
void ILI9340_setWindow(uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1);
void ILI9340_init(void);

void ILI9340_drawChar(uint8_t c, uint16_t x, uint16_t y, uint16_t fcolor, uint16_t bcolor);
void ILI9340_drawCharBig(uint8_t c, uint16_t x, uint16_t y, uint16_t fcolor, uint16_t bcolor, uint8_t m);
void ILI9340_drawString(uint8_t* s, uint16_t x, uint16_t y, uint16_t fcolor, uint16_t bcolor, uint8_t m);
void ILI9340_drawPixel(uint16_t x, uint16_t y, uint16_t color);


int32_t main(void) {
    uint32_t ulx = 0, uly = 0, lrx = TFTWIDTH, lry = TFTHEIGHT;
    uint16_t color = BLUE;
    uint32_t w = ulx - lrx;
    uint32_t h = uly - lry;

    ILI9340_init();

    ILI9340_setWindow(ulx, uly, lrx, lry);
    ILI9340_blockData(w * h, color);

    // Landscape
    ILI9340_command(0x36);
    ILI9340_data(0xD8);

    ILI9340_drawString((uint8_t*)"STM32 NUCLEO-64", 20, 60, RED, YELLOW, 3);
    ILI9340_drawString((uint8_t*)"on EduBase V2", 20, 90, YELLOW, BLUE, 3);

    while(1)
    { }
}

/* draw a character */
void ILI9340_drawChar(uint8_t c, uint16_t x, uint16_t y, uint16_t fcolor, uint16_t bcolor) {
    for (int i = 0; i < FONTWIDTH; i++) {
        uint8_t byte = font5x7[c - ' '][i];
        uint16_t xx = x + i;
        for (int j = 0; j < FONTHEIGHT; j++) {
            uint16_t yy = y + j;
            ILI9340_drawPixel(yy, xx, byte & (1 << j) ? fcolor : bcolor);
        }
    }
}

/* draw a big character */
void ILI9340_drawCharBig(uint8_t c, uint16_t x, uint16_t y, uint16_t fcolor, uint16_t bcolor, uint8_t m) {
    for (int i = 0; i < FONTWIDTH; i++) {
        uint8_t byte = font5x7[c - ' '][i];

        for (int n = 0; n < m; n++) {
            uint16_t xx = x + i * m + n;
            for (int j = 0; j < FONTHEIGHT; j++) {
                uint16_t yy = y + j * m;
                for (int k = 0; k < m; k++) {
                    ILI9340_drawPixel(yy + k, xx, byte & (1 << j) ? fcolor : bcolor);
                }
            }
        }
    }
}

/* draw a string of big characters */
void ILI9340_drawString(uint8_t* s, uint16_t x, uint16_t y, uint16_t fcolor, uint16_t bcolor, uint8_t m) {
    while (*s != 0) {
        ILI9340_drawCharBig(*s, x, y, fcolor, bcolor, m);
        s++;
        x += FONTWIDTH * m;
    }
}

/* draw a pixel */
void ILI9340_drawPixel(uint16_t x, uint16_t y, uint16_t color) {
    if((x < 1) ||(x >= TFTWIDTH) || (y < 1) || (y >= TFTHEIGHT)) return;

    ILI9340_setWindow(x, y, x + 1, y + 1);
    ILI9340_blockData(1, color);
}

/* Initialize SPI for TFT controller */
void SPI_init(void) {
    RCC->AHB1ENR |= 1;              /* enable GPIOA clock */
    RCC->AHB1ENR |= 4;              /* enable GPIOC clock */
    RCC->APB2ENR |= 0x1000;         /* enable SPI1 clock */

    /* PORTA 5, 7 for SPI1 MOSI and SCLK */
    GPIOA->MODER &= ~0x0000CC00;    /* clear pin mode */
    GPIOA->MODER |=  0x00008800;    /* set pin alternate mode */
    GPIOA->AFR[0] &= ~0xF0F00000;   /* clear alt mode */
    GPIOA->AFR[0] |=  0x50500000;   /* set alt mode SPI1 */

    /* PC1 as GPIO output for SPI slave select */
    GPIOC->MODER &= ~0x0000000C;    /* clear pin mode */
    GPIOC->MODER |=  0x00000004;    /* set pin output mode */

    /* PA11 as GPIO output for TFT Command/Data select */
    GPIOA->MODER &= ~0x00C00000;    /* clear pin mode */
    GPIOA->MODER |=  0x00400000;    /* set pin output mode */

    SPI1->CR1 = 0x31F;
    SPI1->CR2 = 0;
    SPI1->CR1 |= 0x40;              /* enable SPI1 module */
}

/* write data to SPI */
void SPI_write(unsigned char data)
{
    ILI9340_assertSS();             /* assert slave select */
    SPI1->DR = data;                /* write data */
    while (SPI1->SR & 0x80) {}      /* wait for transmission done */
    ILI9340_deassertSS();           /* deassert slave select */
}

/* hardware reset of TFT controller */
void ILI9340_hardReset(void) {
    delayMs(2000);
    ILI9340_reset();
    delayMs(1);
    ILI9340_dereset();
    delayMs(2000);
}

/* send a command to TFT controller */
void ILI9340_command(uint8_t command) {
    ILI9340_setCommand();
    ILI9340_assertSS();
    SPI_write(command);
    ILI9340_deassertSS();
}

/* send a data to TFT controller */
void ILI9340_data(uint8_t data) {
    ILI9340_setData();
    ILI9340_assertSS();
    SPI_write(data);
    ILI9340_deassertSS();
}

/* send a block of data to TFT controller */
void ILI9340_blockData(int32_t n, uint16_t color) {
    ILI9340_setData();
    ILI9340_assertSS();
    while (n--) {
        SPI_write(color >> 8);
        SPI_write(color & 0xFF);
    }
    ILI9340_deassertSS();
}

/* set a window in the display to receive data */
void ILI9340_setWindow(uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1) {
    ILI9340_command(ILI9340_CASET); // Column addr set
    ILI9340_data(x0 >> 8);          // XSTART
    ILI9340_data(x0 & 0xFF);
    ILI9340_data(x1 >> 8);          // XEND
    ILI9340_data(x1 & 0xFF);

    ILI9340_command(ILI9340_PASET); // Row addr set
    ILI9340_data(y0>>8);            // YSTART
    ILI9340_data(y0);
    ILI9340_data(y1>>8);            // YEND
    ILI9340_data(y1);

    ILI9340_command(ILI9340_RAMWR); // write to RAM
}

/* initialize the TFT controller */
void ILI9340_init(void) {
    SPI_init();
    ILI9340_hardReset();

    ILI9340_command(0xEF);
    ILI9340_data(0x03);
    ILI9340_data(0x80);
    ILI9340_data(0x02);

    ILI9340_command(0xCF);
    ILI9340_data(0x00);
    ILI9340_data(0xC1);
    ILI9340_data(0x30);

    ILI9340_command(0xED);
    ILI9340_data(0x64);
    ILI9340_data(0x03);
    ILI9340_data(0x12);
    ILI9340_data(0x81);

    ILI9340_command(0xE8);
    ILI9340_data(0x85);
    ILI9340_data(0x00);
    ILI9340_data(0x78);

    ILI9340_command(0xCB);
    ILI9340_data(0x39);
    ILI9340_data(0x2C);
    ILI9340_data(0x00);
    ILI9340_data(0x34);
    ILI9340_data(0x02);

    ILI9340_command(0xF7);
    ILI9340_data(0x20);

    ILI9340_command(0xEA);
    ILI9340_data(0x00);
    ILI9340_data(0x00);

    ILI9340_command(ILI9340_PWCTR1);    //Power control
    ILI9340_data(0x23);   //VRH[5:0]

    ILI9340_command(ILI9340_PWCTR2);    //Power control
    ILI9340_data(0x10);   //SAP[2:0];BT[3:0]

    ILI9340_command(ILI9340_VMCTR1);    //VCM control
    ILI9340_data(0x3e);
    ILI9340_data(0x28);

    ILI9340_command(ILI9340_VMCTR2);    //VCM control2
    ILI9340_data(0x86);

    ILI9340_command(ILI9340_MADCTL);    // Memory Access Control
    ILI9340_data(ILI9340_MADCTL_MX | ILI9340_MADCTL_BGR);

    ILI9340_command(ILI9340_PIXFMT);
    ILI9340_data(0x55);

    ILI9340_command(ILI9340_FRMCTR1);
    ILI9340_data(0x00);
    ILI9340_data(0x18);

    ILI9340_command(ILI9340_DFUNCTR);    // Display Function Control
    ILI9340_data(0x08);
    ILI9340_data(0x82);
    ILI9340_data(0x27);

    ILI9340_command(0xF2);    // 3Gamma Function Disable
    ILI9340_data(0x00);

    ILI9340_command(ILI9340_GAMMASET);    //Gamma curve selected
    ILI9340_data(0x01);

    ILI9340_command(ILI9340_GMCTRP1);    //Set Gamma
    ILI9340_data(0x0F);
    ILI9340_data(0x31);
    ILI9340_data(0x2B);
    ILI9340_data(0x0C);
    ILI9340_data(0x0E);
    ILI9340_data(0x08);
    ILI9340_data(0x4E);
    ILI9340_data(0xF1);
    ILI9340_data(0x37);
    ILI9340_data(0x07);
    ILI9340_data(0x10);
    ILI9340_data(0x03);
    ILI9340_data(0x0E);
    ILI9340_data(0x09);
    ILI9340_data(0x00);

    ILI9340_command(ILI9340_GMCTRN1);    //Set Gamma
    ILI9340_data(0x00);
    ILI9340_data(0x0E);
    ILI9340_data(0x14);
    ILI9340_data(0x03);
    ILI9340_data(0x11);
    ILI9340_data(0x07);
    ILI9340_data(0x31);
    ILI9340_data(0xC1);
    ILI9340_data(0x48);
    ILI9340_data(0x08);
    ILI9340_data(0x0F);
    ILI9340_data(0x0C);
    ILI9340_data(0x31);
    ILI9340_data(0x36);
    ILI9340_data(0x0F);

    ILI9340_command(ILI9340_SLPOUT);    //Exit Sleep
    delayMs(120);
    ILI9340_command(ILI9340_DISPON);    //Display on
}

/* 16 MHz SYSCLK */
void delayMs(int n) {
    int i;
    for (; n > 0; n--)
        for (i = 0; i < 3195; i++) ;
}