LCD编程_使用调色板

在前面的博客中，使用的像素格式都是16bpp，24bpp（24bpp实际实际上就是32bpp）？如果想使用8bpp时，就需要使用调色板。

在以前的博客中，曾经说过，在framebuffer中如果每个像素用8bpp表示，这8bpp怎么转换成lcd需要的16bpp的数据，需要引入一个调色板。

2的8次方，为256。即调色板中有256项，0-255。需要在调色板所对应的内存里面，填入16bpp的数据（这些数据就是真正的颜色值）。把lcd控制器设置为8bpp时，它会从framebuffer中取出一个像素的数据（8位），使用这8位数据作为一个索引，在调色板中取出真正的颜色，从而就得到了16位的数据。最终将这16位的数据发给lcd。

需要修改s3c2440_lcd_controller.c    lcd_controller.c中的代码：

 #include "lcd.h"
 #include "lcd_controller.h"
 #include "../s3c2440_soc.h"

 #define HCLK 100

 void jz2440_lcd_pin_init(void)
 {
     /* 初始化引脚 : 背光引脚 */
     GPBCON &= ~0x3;
     GPBCON |= 0x01;

     /* LCD专用引脚 */
     GPCCON = 0xaaaaaaaa;
     GPDCON = 0xaaaaaaaa;

     /* PWREN */
     GPGCON |= (<<);
 }

 /* 根据传入的LCD参数设置LCD控制器 */
 void s3c2440_lcd_controller_init(p_lcd_params plcdparams)
 {
     int pixelplace;
     unsigned int addr;

     jz2440_lcd_pin_init();

     /* [17:8]: clkval, vclk = HCLK / [(CLKVAL+1) x 2]
      *                   9   = 100M /[(CLKVAL+1) x 2], clkval = 4.5 = 5
      *                 CLKVAL = 100/vclk/2-1
      * [6:5]: 0b11, tft lcd
      * [4:1]: bpp mode
      * [0]  : LCD video output and the logic enable/disable
      */
     int clkval = (float)HCLK/plcdparams->time_seq.vclk/-+0.5;
     //int clkval = 5;
     int bppmode = plcdparams->bpp ==   ? 0xb :\
                   plcdparams->bpp ==  ? 0xc :\
                   0xd;  /* 0xd: 24,32bpp */
     LCDCON1 = (clkval<<) | (<<) | (bppmode<<) ;

     /* [31:24] : VBPD    = tvb - 1
      * [23:14] : LINEVAL = line - 1
      * [13:6]  : VFPD    = tvf - 1
      * [5:0]   : VSPW    = tvp - 1
      */
     LCDCON2 =     ((plcdparams->time_seq.tvb - )<<) | \
                 ((plcdparams->yres - )<<)         | \
                 ((plcdparams->time_seq.tvf - )<<)  | \
                 ((plcdparams->time_seq.tvp - )<<);

     /* [25:19] : HBPD     = thb - 1
      * [18:8]  : HOZVAL  = 列 - 1
      * [7:0]   : HFPD     = thf - 1
      */
     LCDCON3 =    ((plcdparams->time_seq.thb - )<<) | \
                 ((plcdparams->xres - )<<)              | \
                 ((plcdparams->time_seq.thf - )<<);

     /*
      * [7:0]   : HSPW     = thp - 1
      */
     LCDCON4 =    ((plcdparams->time_seq.thp - )<<);

     /* 用来设置引脚极性, 设置16bpp, 设置内存中象素存放的格式
      * [12] : BPP24BL
      * [11] : FRM565, 1-565
      * [10] : INVVCLK, 0 = The video data is fetched at VCLK falling edge
      * [9]  : HSYNC是否反转
      * [8]  : VSYNC是否反转
      * [7]  : INVVD, rgb是否反转
      * [6]  : INVVDEN
      * [5]  : INVPWREN
      * [4]  : INVLEND
      * [3]  : PWREN, LCD_PWREN output signal enable/disable
      * [2]  : ENLEND
      * [1]  : BSWP
      * [0]  : HWSWP
      */

     pixelplace = plcdparams->bpp ==  ? () : \
                  plcdparams->bpp ==  ? () : \
                  (<<);  /* 8bpp */

     LCDCON5 = (plcdparams->pins_pol.vclk<<) |\
               (plcdparams->pins_pol.rgb<<)   |\
               (plcdparams->pins_pol.hsync<<) |\
               (plcdparams->pins_pol.vsync<<) |\
                (plcdparams->pins_pol.de<<)    |\
               (plcdparams->pins_pol.pwren<<) |\
               (<<) | pixelplace;

     /* framebuffer地址 */
     /*
      * [29:21] : LCDBANK, A[30:22] of fb
      * [20:0]  : LCDBASEU, A[21:1] of fb
      */
     addr = plcdparams->fb_base & ~(<<);
     LCDSADDR1 = (addr >> );

     /*
      * [20:0] : LCDBASEL, A[21:1] of end addr
      */
     addr = plcdparams->fb_base + plcdparams->xres*plcdparams->yres*plcdparams->bpp/;
     addr >>=;
     addr &= 0x1fffff;
     LCDSADDR2 = addr;//
 }

 void s3c2440_lcd_controller_enalbe(void)
 {
     /* 背光引脚 : GPB0 */
     GPBDAT |= (<<);

     /* pwren    : 给LCD提供AVDD  */
     LCDCON5 |= (<<);

     /* LCDCON1'BIT 0 : 设置LCD控制器是否输出信号 */
     LCDCON1 |= (<<);
 }

 void s3c2440_lcd_controller_disable(void)
 {
     /* 背光引脚 : GPB0 */
     GPBDAT &= ~(<<);

     /* pwren    : 给LCD提供AVDD  */
     LCDCON5 &= ~(<<);

     /* LCDCON1'BIT 0 : 设置LCD控制器是否输出信号 */
     LCDCON1 &= ~(<<);
 }

 /* 设置调色板之前, 先关闭lcd_controller */
138 void s3c2440_lcd_controller_init_palette(void)
139 {
140     volatile unsigned int *palette_base =  (volatile unsigned int *)0x4D000400;
141     int i;
142
143     int bit = LCDCON1 & (1<<0);
144
145     /* LCDCON1'BIT 0 : 设置LCD控制器是否输出信号 */
146     if (bit)
147         LCDCON1 &= ~(1<<0);
148
149     for (i = 0; i < 256; i++)
150     {
151         /* 低16位 : rgb565 */
152         *palette_base++ = i;
153     }
154
155     if (bit)
156         LCDCON1 |= (1<<0);
157 }

 struct lcd_controller s3c2440_lcd_controller = {
     .name    = "s3c2440",
     .init    = s3c2440_lcd_controller_init,
     .enable  = s3c2440_lcd_controller_enalbe,
     .disable = s3c2440_lcd_controller_disable,
     .init_palette = s3c2440_lcd_controller_init_palette,
 };

 void s3c2440_lcd_contoller_add(void)
 {
     register_lcd_controller(&s3c2440_lcd_controller);
 }

 #include "lcd_controller.h"

 #define LCD_CONTROLLER_NUM 10

 static p_lcd_controller p_array_lcd_controller[LCD_CONTROLLER_NUM];
 static p_lcd_controller g_p_lcd_controller_selected;

 int register_lcd_controller(p_lcd_controller plcdcon)
 {
     int i;
     for (i = ; i < LCD_CONTROLLER_NUM; i++)
     {
         if (!p_array_lcd_controller[i])
         {
             p_array_lcd_controller[i] = plcdcon;
             return i;
         }
     }
     return -;
 }

 int select_lcd_controller(char *name)
 {
     int i;
     for (i = ; i < LCD_CONTROLLER_NUM; i++)
     {
         if (p_array_lcd_controller[i] && !strcmp(p_array_lcd_controller[i]->name, name))
         {
             g_p_lcd_controller_selected = p_array_lcd_controller[i];
             return i;
         }
     }
     return -;
 }

 /* 向上: 接收不同LCD的参数
  * 向下: 使用这些参数设置对应的LCD控制器
  */

 int lcd_controller_init(p_lcd_params plcdparams)
 {
     /* 调用所选择的LCD控制器的初始化函数 */
     if (g_p_lcd_controller_selected)
     {
         g_p_lcd_controller_selected->init(plcdparams);
         g_p_lcd_controller_selected->init_palette();
         return ;
     }
     return -;
 }

 void lcd_controller_enable(void)
 {
     if (g_p_lcd_controller_selected)
     {
         g_p_lcd_controller_selected->enable();
     }
 }

 void lcd_controller_disable(void)
 {
     if (g_p_lcd_controller_selected)
     {
         g_p_lcd_controller_selected->disable();
     }
 }

 void lcd_contoller_add(void)
 {
     s3c2440_lcd_contoller_add();
 }

再来看一下，lcd_4.3中，做了什么修改？

led_test.c，注意：这里面的颜色值都是随便写的。目的就是想看看，使用8bpp时，能够实现功能。

 #include "geometry.h"
 #include "font.h"

 void lcd_test(void)
 {
     unsigned int fb_base;
     int xres, yres, bpp;
     int x, y;
     unsigned char *p0;
     unsigned short *p;
     unsigned int *p2;

     /* 初始化LCD */
     lcd_init();

     /* 使能LCD */
     lcd_enable();

     /* 获得LCD的参数: fb_base, xres, yres, bpp */
     get_lcd_params(&fb_base, &xres, &yres, &bpp);
     fb_get_lcd_params();
     font_init();

     /* 往framebuffer中写数据 */
     if (bpp == )
     {
         /* 让LCD输出整屏的红色 */

         /* bpp: palette[12] */

         p0 = (unsigned char *)fb_base;
         for (x = ; x < xres; x++)
             for (y = ; y < yres; y++)
                 *p0++ = ;

         /* palette[47] */
         p0 = (unsigned char *)fb_base;
         for (x = ; x < xres; x++)
             for (y = ; y < yres; y++)
                 *p0++ = ;

         /* palette[88] */
         p0 = (unsigned char *)fb_base;
         for (x = ; x < xres; x++)
             for (y = ; y < yres; y++)
                 *p0++ = ;

         /* palette[0] */
         p0 = (unsigned char *)fb_base;
         for (x = ; x < xres; x++)
             for (y = ; y < yres; y++)
                 *p0++ = ;

     }
     else if (bpp == )
     {
         /* 让LCD输出整屏的红色 */

         /* 565: 0xf800 */

         p = (unsigned short *)fb_base;
         for (x = ; x < xres; x++)
             for (y = ; y < yres; y++)
                 *p++ = 0xf800;

         /* green */
         p = (unsigned short *)fb_base;
         for (x = ; x < xres; x++)
             for (y = ; y < yres; y++)
                 *p++ = 0x7e0;

         /* blue */
         p = (unsigned short *)fb_base;
         for (x = ; x < xres; x++)
             for (y = ; y < yres; y++)
                 *p++ = 0x1f;

         /* black */
         p = (unsigned short *)fb_base;
         for (x = ; x < xres; x++)
             for (y = ; y < yres; y++)
                 *p++ = ;

     }
     else if (bpp == )
     {
         /* 让LCD输出整屏的红色 */

         /* 0xRRGGBB */

         p2 = (unsigned int *)fb_base;
         for (x = ; x < xres; x++)
             for (y = ; y < yres; y++)
                 *p2++ = 0xff0000;

         /* green */
         p2 = (unsigned int *)fb_base;
         for (x = ; x < xres; x++)
             for (y = ; y < yres; y++)
                 *p2++ = 0x00ff00;

         /* blue */
         p2 = (unsigned int *)fb_base;
         for (x = ; x < xres; x++)
             for (y = ; y < yres; y++)
                 *p2++ = 0x0000ff;

         /* black */
         p2 = (unsigned int *)fb_base;
         for (x = ; x < xres; x++)
             for (y = ; y < yres; y++)
                 *p2++ = ;

     }

     delay();

     /* 画线 */
     draw_line(, , xres - , , 0x23ff77);
     draw_line(xres - , , xres - , yres - , 0xffff);
     draw_line(, yres - , xres - , yres - , 0xff00aa);
     draw_line(, , , yres - , 0xff00ef);
     draw_line(, , xres - , yres - , 0xff45);
     draw_line(xres - , , , yres - , 0xff0780);

     delay();

     /* 画圆 */
     draw_circle(xres/, yres/, yres/, 0xff);

     /* 输出文字 */
     fb_print_string(, , "www.100ask.net\n\r100ask.taobao.com", 0xff);
 }