裸机系列代码地址:链接:http://pan.baidu.com/s/1pLHOd0v 密码:4x5s
S3C2440支持STN、TFT、SEC TFT三种类型的LCD显示器
下面看一看64K(16BPP)色下的内存位置与像素位置的关系图
LCD控制器中的REGBANK的17个寄存器可以分为6类,在一般应用中我们只需用到三类共9个寄存器[23:0]:TPALVAL,颜色值
LCD编程注意事项:
1、必须打开LCD背光电路,否则,LCD不会亮
2、在写LCDADDR3之前必须使得LCDCON1[0]=0,而相关寄存器全部设置好之后LCDCON1[0]=1
3、别忘记将S3C2440相应引脚设为为LCD使用
4、设置LCD_PWREN有效,它用于打开LCD的电源
5、程序中应该设置一个死循环,否则程序会一闪而过
下面是一个LCD的实例
Makefile文件
objs := head.o init.o main.o
lcd.bin: $(objs)
arm-linux-ld -Tlcd.lds -o lcd_elf $^
arm-linux-objcopy -O binary -S lcd_elf $@
arm-linux-objdump -D -m arm lcd_elf > lcd.dis
%.o:%.c
arm-linux-gcc -Wall -O2 -c -o $@ $<
%.o:%.S
arm-linux-gcc -Wall -O2 -c -o $@ $<
clean:
rm -f lcd.bin lcd_elf lcd.dis *.o
链接文件lcd.lds
SECTIONS {
. = 0x30000000;
.text : { *(.text) }
.rodata ALIGN(4) : {*(.rodata)}
.data ALIGN(4) : { *(.data) }
.bss ALIGN(4) : { *(.bss) *(COMMON) }
}
head.S文件
.extern main
.text
.global _start
_start:
Reset:
ldr sp, =4096 /*设置C函数的栈*/
bl disable_watch_dog /*关看门狗*/
bl clock_init /*初始化时钟FCLK:HCLK:PCLK=200MHZ:100MHZ:50MHZ*/
bl memsetup /*存储控制器初始化,使得SDRAM可用*/
bl copy_steppingstone_to_sdram /*将代码复制到SDRAM 中*/
ldr pc, =on_sdram /*地址相关代码,从这里开始,代码跳到SDRAM中运行*/
on_sdram:
ldr sp, =0x34000000 /*重新设置C函数堆栈*/
ldr lr, =halt_loop
ldr pc, =main /*跳转到main函数中执行*/
halt_loop:
b halt_loop
init.c文件
#include "s3c2440.h"
void disable_watch_dog(void);
void clock_init(void);
void memsetup(void);
void copy_steppingstone_to_sdram(void);
/*
* 关闭WATCHDOG,否则CPU会不断重启
*/
void disable_watch_dog(void)
{
WTCON = 0; // 关闭WATCHDOG很简单,往这个寄存器写0即可
}
#define S3C2410_MPLL_200MHZ ((0x5c<<12)|(0x04<<4)|(0x00))
#define S3C2440_MPLL_200MHZ ((0x5c<<12)|(0x01<<4)|(0x02))
/*
* 对于MPLLCON寄存器,[19:12]为MDIV,[9:4]为PDIV,[1:0]为SDIV
* 有如下计算公式:
* S3C2410: MPLL(FCLK) = (m * Fin)/(p * 2^s)
* S3C2440: MPLL(FCLK) = (2 * m * Fin)/(p * 2^s)
* 其中: m = MDIV + 8, p = PDIV + 2, s = SDIV
* 对于本开发板,Fin = 12MHz
* 设置CLKDIVN,令分频比为:FCLK:HCLK:PCLK=1:2:4,
* FCLK=200MHz,HCLK=100MHz,PCLK=50MHz
*/
void clock_init(void)
{
// LOCKTIME = 0x00ffffff; // 使用默认值即可
CLKDIVN = 0x03; // FCLK:HCLK:PCLK=1:2:4, HDIVN=1,PDIVN=1
/* 如果HDIVN非0,CPU的总线模式应该从“fast bus mode”变为“asynchronous bus mode” */
__asm__(
"mrc p15, 0, r1, c1, c0, 0\n" /* 读出控制寄存器 */
"orr r1, r1, #0xc0000000\n" /* 设置为“asynchronous bus mode” */
"mcr p15, 0, r1, c1, c0, 0\n" /* 写入控制寄存器 */
);
MPLLCON = S3C2440_MPLL_200MHZ; /* 现在,FCLK=200MHz,HCLK=100MHz,PCLK=50MHz */
}
/*
* 设置存储控制器以使用SDRAM
*/
void memsetup(void)
{
volatile unsigned long *p = (volatile unsigned long *)MEM_CTL_BASE;
/* 这个函数之所以这样赋值,而不是像前面的实验(比如mmu实验)那样将配置值
* 写在数组中,是因为要生成”位置无关的代码”,使得这个函数可以在被复制到
* SDRAM之前就可以在steppingstone中运行
*/
/* 存储控制器13个寄存器的值 */
p[0] = 0x22011110; //BWSCON
p[1] = 0x00000700; //BANKCON0
p[2] = 0x00000700; //BANKCON1
p[3] = 0x00000700; //BANKCON2
p[4] = 0x00000700; //BANKCON3
p[5] = 0x00000700; //BANKCON4
p[6] = 0x00000700; //BANKCON5
p[7] = 0x00018005; //BANKCON6
p[8] = 0x00018005; //BANKCON7
p[9] = 0x008C04F4;
p[10] = 0x000000B1; //BANKSIZE
p[11] = 0x00000030; //MRSRB6
p[12] = 0x00000030; //MRSRB7
}
void copy_steppingstone_to_sdram(void)
{
unsigned int *pdwSrc = (unsigned int *)0;
unsigned int *pdwDest = (unsigned int *)0x30000000;
while (pdwSrc < (unsigned int *)4096)
{
*pdwDest = *pdwSrc;
pdwDest++;
pdwSrc++;
}
}
main.c文件
#include "s3c2440.h"
#define GLOBAL_CLK 1
#define LOWER21BITS(n) ((n) & 0x1fffff)
#define BPPMODE_16BPP 0xC
#define LCDTYPE_TFT 0x3
#define ENVID_DISABLE 0
#define FORMAT8BPP_565 1
#define VSYNC_INV 1
#define HWSWP 1
#define HSYNC_INV 1
#define LCDFRAMEBUFFER 0x30400000
#define UINT32 unsigned int
#define UINT16 unsigned short
#define UINT8 unsigned char
unsigned int fb_base_addr;
unsigned int bpp;
unsigned int xsize;
unsigned int ysize;
#define GPB0_MSK (3<<(0*2))
#define GPB0_out (1<<(0*2))
/*演示函数*/
void delay(int times)
{
int i,j;
for(i=0;i> 19) & 0x1f;
green = (color >> 10) & 0x3f;
blue = (color >> 3) & 0x1f;
color = (red << 11) | (green << 5) | blue; // 格式5:6:5
*addr = (UINT16) color;
}
void DrawLine(int x1,int y1,int x2,int y2,int color)
{
int dx,dy,e;
dx=x2-x1;
dy=y2-y1;
if(dx>=0)
{
if(dy >= 0) // dy>=0
{
if(dx>=dy) // 1/8 octant
{
e=dy-dx/2;
while(x1<=x2)
{
PutPixel(x1,y1,color);
if(e>0){y1+=1;e-=dx;}
x1+=1;
e+=dy;
}
}
else // 2/8 octant
{
e=dx-dy/2;
while(y1<=y2)
{
PutPixel(x1,y1,color);
if(e>0){x1+=1;e-=dy;}
y1+=1;
e+=dx;
}
}
}
else // dy<0
{
dy=-dy; // dy=abs(dy)
if(dx>=dy) // 8/8 octant
{
e=dy-dx/2;
while(x1<=x2)
{
PutPixel(x1,y1,color);
if(e>0){y1-=1;e-=dx;}
x1+=1;
e+=dy;
}
}
else // 7/8 octant
{
e=dx-dy/2;
while(y1>=y2)
{
PutPixel(x1,y1,color);
if(e>0){x1+=1;e-=dy;}
y1-=1;
e+=dx;
}
}
}
}
else //dx<0
{
dx=-dx; //dx=abs(dx)
if(dy >= 0) // dy>=0
{
if(dx>=dy) // 4/8 octant
{
e=dy-dx/2;
while(x1>=x2)
{
PutPixel(x1,y1,color);
if(e>0){y1+=1;e-=dx;}
x1-=1;
e+=dy;
}
}
else // 3/8 octant
{
e=dx-dy/2;
while(y1<=y2)
{
PutPixel(x1,y1,color);
if(e>0){x1-=1;e-=dy;}
y1+=1;
e+=dx;
}
}
}
else // dy<0
{
dy=-dy; // dy=abs(dy)
if(dx>=dy) // 5/8 octant
{
e=dy-dx/2;
while(x1>=x2)
{
PutPixel(x1,y1,color);
if(e>0){y1-=1;e-=dx;}
x1-=1;
e+=dy;
}
}
else // 6/8 octant
{
e=dx-dy/2;
while(y1>=y2)
{
PutPixel(x1,y1,color);
if(e>0){x1-=1;e-=dy;}
y1-=1;
e+=dx;
}
}
}
}
}
void ClearScr(UINT32 color)
{
UINT32 x,y;
for (y = 0; y < ysize; y++)
for (x = 0; x < xsize; x++)
PutPixel(x, y, color);
}
/*LCD开关*/
void Lcd_EnvidOnOff(int onoff)
{
if (onoff == 1)
{
LCDCON1 |= 1; // ENVID ON
GPBDAT |= (1<<0); // Power on
}
else
{
LCDCON1 &= 0x3fffe; // ENVID Off
GPBDAT &= ~(1<<0); // Power off
}
}
/*端口初始化*/
void Lcd_Port_Init(void)
{
GPCUP = 0xffffffff; // 禁止内部上拉
GPCCON = 0xaaaaaaaa; // GPIO管脚用于VD[7:0],LCDVF[2:0],VM,VFRAME,VLINE,VCLK,LEND
GPDUP = 0xffffffff; // 禁止内部上拉
GPDCON = 0xaaaaaaaa; // GPIO管脚用于VD[23:8]
GPBCON &= ~(GPB0_MSK); /*下面三行打开LCD背光驱动电路*/
GPBCON |= GPB0_out;
GPBDAT &= ~(1<<0);
}
void Tft_Lcd_Init(void)
{
/*
* 设置LCD控制器的控制寄存器LCDCON1~5
* 1. LCDCON1:
* 设置VCLK的频率:VCLK(Hz) = HCLK/[(CLKVAL+1)x2]
* 选择LCD类型: TFT LCD
* 设置显示模式: 16BPP
* 先禁止LCD信号输出
* 2. LCDCON2/3/4:
* 设置控制信号的时间参数
* 设置分辨率,即行数及列数
* 现在,可以根据公式计算出显示器的频率:
* 当HCLK=100MHz时,
* Frame Rate = 1/[{(VSPW+1)+(VBPD+1)+(LIINEVAL+1)+(VFPD+1)}x
* {(HSPW+1)+(HBPD+1)+(HFPD+1)+(HOZVAL+1)}x
* {2x(CLKVAL+1)/(HCLK)}]
* = 60Hz
* 3. LCDCON5:
* 设置显示模式为16BPP时的数据格式: 5:6:5
* 设置HSYNC、VSYNC脉冲的极性(这需要参考具体LCD的接口信号): 反转
* 半字(2字节)交换使能
*/
LCDCON1 = (4<<8) | (LCDTYPE_TFT<<5) | \
(BPPMODE_16BPP<<1) | (ENVID_DISABLE<<0);
LCDCON2 = (1<<24) | (271<<14) | \
(1<<6) | (9);
LCDCON3 = (1<<19) | (479<<8) | (1);
LCDCON4 = 40;
LCDCON5 = (1<<11) | (1 << 9) | (1 << 8) | (1 << 3) | (0<<1)|(1 << 0);
/*
* 设置LCD控制器的地址寄存器LCDSADDR1~3
* 帧内存与视口(view point)完全吻合,
* 图像数据格式如下:
* |----PAGEWIDTH----|
* y/x 0 1 2 239
* 0 rgb rgb rgb ... rgb
* 1 rgb rgb rgb ... rgb
* 1. LCDSADDR1:
* 设置LCDBANK、LCDBASEU
* 2. LCDSADDR2:
* 设置LCDBASEL: 帧缓冲区的结束地址A[21:1]
* 3. LCDSADDR3:
* OFFSIZE等于0,PAGEWIDTH等于(240*2/2)
*/
LCDSADDR1 = ((LCDFRAMEBUFFER>>22)<<21) | LOWER21BITS(LCDFRAMEBUFFER>>1);
LCDSADDR2 = LOWER21BITS((LCDFRAMEBUFFER+ \
(480)*(272)*2)>>1);
LCDSADDR3 = (0<<11) | (480*2/2);
/* 禁止临时调色板寄存器 */
TPAL = 0;
fb_base_addr = LCDFRAMEBUFFER;
bpp = 8;
xsize = 480;
ysize = 272;
}
void Lcd_PowerEnable(int invpwren, int pwren)
{
LCDCON5 = (LCDCON5 & (~(1<<5))) | (invpwren<<5); // 设置LCD_PWREN的极性: 正常/反转
LCDCON5 = (LCDCON5 & (~(1<<3))) | (pwren<<3); // 设置是否输出LCD_PWREN
}
/*主函数*/
int main(void)
{
Lcd_Port_Init(); // 设置LCD引脚,打开背光电路
Tft_Lcd_Init(); // 初始化LCD控制器
Lcd_PowerEnable(0, 1); // 设置LCD_PWREN有效,它用于打开LCD的电源
Lcd_EnvidOnOff(1); // LCD信号输出使能,LCDCON1[0]=0,才可写LCDADDR2,写完LCDADDR2应使能LCD信号输出
ClearScr(0x0); // 清屏,黑色
DrawLine(0 , 0 , 479, 0 , 0xff0000); // 红色
DrawLine(0 , 0 , 0 , 271, 0x00ff00); // 绿色
DrawLine(479, 0 , 479, 271, 0x0000ff); // 蓝色
DrawLine(0 , 271, 479, 271, 0xffffff); // 白色
DrawLine(0 , 0 , 479, 271, 0xffff00); // 黄色
DrawLine(479, 0 , 0 , 271, 0x8000ff); // 紫色
DrawLine(240, 0 , 240, 271, 0xe6e8fa); // 银色
DrawLine(0 , 136, 479, 136, 0xcd7f32); // 金色
while(1);
Lcd_EnvidOnOff(0);
return 0;
}
头文件
/* WOTCH DOG register */
#define WTCON (*(volatile unsigned long *)0x53000000)
/* SDRAM regisers */
#define MEM_CTL_BASE 0x48000000
#define SDRAM_BASE 0x30000000
/*GPIO registers*/
#define GPBCON (*(volatile unsigned long *)0x56000010)
#define GPBDAT (*(volatile unsigned long *)0x56000014)
/*clock registers*/
#define LOCKTIME (*(volatile unsigned long *)0x4c000000)
#define MPLLCON (*(volatile unsigned long *)0x4c000004)
#define UPLLCON (*(volatile unsigned long *)0x4c000008)
#define CLKCON (*(volatile unsigned long *)0x4c00000c)
#define CLKSLOW (*(volatile unsigned long *)0x4c000010)
#define CLKDIVN (*(volatile unsigned long *)0x4c000014)
// LCD CONTROLLER
#define LCDCON1 (*(volatile unsigned long *)0x4d000000) //LCD control 1
#define LCDCON2 (*(volatile unsigned long *)0x4d000004) //LCD control 2
#define LCDCON3 (*(volatile unsigned long *)0x4d000008) //LCD control 3
#define LCDCON4 (*(volatile unsigned long *)0x4d00000c) //LCD control 4
#define LCDCON5 (*(volatile unsigned long *)0x4d000010) //LCD control 5
#define LCDSADDR1 (*(volatile unsigned long *)0x4d000014) //STN/TFT Frame buffer start address 1
#define LCDSADDR2 (*(volatile unsigned long *)0x4d000018) //STN/TFT Frame buffer start address 2
#define LCDSADDR3 (*(volatile unsigned long *)0x4d00001c) //STN/TFT Virtual screen address set
#define REDLUT (*(volatile unsigned long *)0x4d000020) //STN Red lookup table
#define GREENLUT (*(volatile unsigned long *)0x4d000024) //STN Green lookup table
#define BLUELUT (*(volatile unsigned long *)0x4d000028) //STN Blue lookup table
#define DITHMODE (*(volatile unsigned long *)0x4d00004c) //STN Dithering mode
#define TPAL (*(volatile unsigned long *)0x4d000050) //TFT Temporary palette
#define LCDINTPND (*(volatile unsigned long *)0x4d000054) //LCD Interrupt pending
#define LCDSRCPND (*(volatile unsigned long *)0x4d000058) //LCD Interrupt source
#define LCDINTMSK (*(volatile unsigned long *)0x4d00005c) //LCD Interrupt mask
#define TCONSEL (*(volatile unsigned long *)0X4D000060) //LPC3600 Control
#define PALETTE 0x4d000400 //Palette start address