s3c2440 lcd display picture bare metal program

Because the previous bare metal program is very simple, I won’t blog about it.

Program flow:

1. Initialize C SP 

2. Turn off the watchdog

3. Initialize SDRAM

4. Read the program containing pictures in NAND FLASH and put it into SDRAM.

5. Jump to SDRAM for execution

Because the 2440 automatically only reads 4K to SRAM, if you put pictures in it, it will naturally not be enough. It's just one more step to put it in SDRAM.

I didn't directly copy the program in the tutorial, that one is more complicated. C library files are used. 

In the tutorial, we just draw lines, and drawing circular lines is very simple.

At the beginning, I used 24BPP to develop, so I encountered many problems.

The picture needs to be converted into a C language header file. I see that there are many people on the Internet looking for software to convert, and there is also one who uses C to convert under LINUX. I looked for a software, it was made by MFC, but it didn't support 24BPP. 

I can only do it myself. Written in python. The link is here: http://www.cnblogs.com/ningci/p/5203053.html

16BPP:

//lcd controller

typedef struct{

    unsigned long LCDCON1;

    unsigned long LCDCON2;

    unsigned long LCDCON3;

    unsigned long LCDCON4;

    unsigned long LCDCON5;

    unsigned long LCDSADDR1;

    unsigned long LCDSADDR2;

    unsigned long LCDSADDR3;

    unsigned long REDLUT;

    unsigned long GREENLUT;

    unsigned long BLUELUT;

    unsigned long DITHMODE;

    unsigned long TPAL;

} LCD;

LCD * lcd = (LCD *)0x4d000000;

#define GPBCON (*(volatile unsigned long *)0x56000010)

#define GPBDAT (*(volatile unsigned long *)0x56000014)

#define GPCUP (*(volatile unsigned long *)0x56000028)

#define GPCCON (*(volatile unsigned long *)0x56000020)

#define GPDUP (*(volatile unsigned long *)0x56000038)

#define GPDCON (*(volatile unsigned long *)0x56000030)

#define GPGUP (*(volatile unsigned long *)0x56000068)

#define GPGCON (*(volatile unsigned long *)0x56000060)

#define HCLK 100000000

#define LCD_WIDTH 480

#define LCD_HEIGHT 272

#define LCD_CLKVAL 4

#define LCD_TFT 3

#define LCD_24BBP 0xd

#define LCD_16BBP 0xc

#define LCD_EN_OFF 0

#define LCD_EN_ON 1

#define LCD_VBPD 1

#define LCD_LINEVAL (LCD_HEIGHT - 1)

#define LCD_VFPD 1

#define LCD_VSPW 9

#define LCD_HBPD 1

#define LCD_HOZVAL (LCD_WIDTH - 1)

#define LCD_HFPD 1

#define LCD_HSPW 40

#define LCD_INVVLINE 1

#define LCD_INVVFRAME 1

#define LCD_FRAMEBUFFER 0x30400000 //4M aligned address

void wait(s)

{

    while(s--);

}

void init_lcd()

{

    //LCD_PWREN

    GPGUP = 0xffffffff; // Disable internal pull-up

    GPGCON = 3<<8;

    GPCUP = 0xffffffff; // Disable internal pull-up

    GPCCON = 0xaaaaaaaa; // GPIO pins for VD[7:0], LCDVF[2:0], VM, VFRAME, VLINE, VCLK, LEND 

    GPDUP = 0xffffffff; // Disable internal pull-up

    GPDCON = 0xaaaaaaaa; // GPIO pins for VD[23:8]

    //GPB0 KEYBOARD

    //backlight on

    GPBCON &= ~(3);

    GPBCON |= 1;

    //HCLK 100M LCD CLK 9M 100/9/2-1=4

    //The default is not enabled

    lcd->LCDCON1 = LCD_CLKVAL<<8 | LCD_TFT<<5 | LCD_16BBP<<1 | LCD_EN_OFF;

    lcd->LCDCON2 = LCD_VBPD<<24 | LCD_LINEVAL<<14 | LCD_VFPD<<6 | LCD_VSPW;

    lcd->LCDCON3 = LCD_HBPD<<19 | LCD_HOZVAL<<8 | LCD_HFPD;

    lcd->LCDCON4 = LCD_HSPW;

    //8bpp BSWP 1 16bpp HWSWP 1 24bpp 0 0 

    lcd->LCDCON5 = 1<<11 | LCD_INVVLINE<<9 | LCD_INVVFRAME<<8 | 1;

    //The address is stored separately and the 31:22 bits can be shifted to the right. The 21:1 bits are used & the upper 21 1s are cleared if the high bit is not 7.

    lcd->LCDSADDR1 = (LCD_FRAMEBUFFER>>22)<<21 | ((LCD_FRAMEBUFFER>>1) & 0x1fffff);

    //24bpp occupies 4 lengths of 16bpp, 2 lengths of 8bpp and 1 length 

    lcd->LCDSADDR2 = ((LCD_FRAMEBUFFER + LCD_WIDTH * LCD_HEIGHT*2)>>1) & 0x1fffff;

    lcd->LCDSADDR3 = LCD_WIDTH;

    lcd->TPAL = 0;

}

void lcd_on()

{

    //backlight on

    GPBDAT |= 1;

    lcd->LCDCON1 |= LCD_EN_ON;

    lcd->LCDCON5 |= 0x3<<2;

}

void lcd_off()

{

    //Backlight off

    GPBDAT &= 0;

    lcd->LCDCON1 &= LCD_EN_OFF;

    lcd->LCDCON5 &= ~(0x3<<2);

}

void show_img(unsigned short *img)

{

    int i=0;

    //Video memory address

    unsigned short * frame_buf = (volatile unsigned short *)LCD_FRAMEBUFFER;

    for(i=0;i<(480*272);i++)

    {

        *frame_buf = *img;

        frame_buf++;

        img++;

    }

}

#include "img1.h"

int main()

{

    init_lcd();

    lcd_on();

    show_img(&img1);

    return 0;

}

Just write the color value directly into the memory and display it on the screen.

The following is the display rendering: