一、LCD时序配置
fl2440开发板的LCD是3.5寸屏型号是WXCAT35-TG3#001，这是一款320x240分辨率的TFT LCD屏，先来了解一下TFT LCD的时序如下：
图1 TFT LCD时序
（1）VSYNC信号来一个脉冲时，表示一帧的开始
（2） VSPW表示VSYNC信号的脉冲宽度为（VSPW+1）个HSYNC信号周期，即（VSPW+1）行，这（VSPW+1）行的数据无效。
（3）VSYNC信号脉冲之后，还要经过（VBPD+1）个（HSYNC）信号周期，有效的行数据才出现。所以，在VSYNC信号有效之后，总共还要经过（VSPW+1+VBPD+1）个无效行，
（4）随后连续发出（LINEVAL+1）行的有效数据
（5）最后是（VFPD+1）个无效行，完整的一帧结束，紧接着就是下一帧的数据了（即下一个VSYNC信号）。
（6）HSYNC信号有效时，表示一行数据的开始
（7） HSPW表示HSYNC信号的脉冲宽度为（HSPW+1）个VCLK信号周期，即（HSPW+1）个像素，这（HSPW+1）个像素的数据无效。
（8）HSYNC信号脉冲之后，还要经过（HBPD+1）个VCLK信号周期，有效的像素数据才会出现。所以，在HSYNC信号有效之后，总共还要经过（HSPW + 1 + HBPD + 1）个无效的像素，第一个有效像素才出现。
（9）随后即连续发出（HOZVAL+1）个像素的有效数据。
（10）最后是（HFPD+1）个无效的像素，完整的一行结束，紧接着就是下一行的数据了（即下一个HSYNC信号）。
TFT LCD的正常工作主要需要配置S3C2440的寄存器LCDCON1~LCDCON5。
二、u-boot支持LCD的配置工作
首先要添加一个文件，driver/video/s3c2410_fb.c，其内容为：/*
* (C) Copyright 2006 by OpenMoko, Inc.
* Author: Harald Welte <laforge@openmoko.org>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include <common.h>
#if defined(CONFIG_VIDEO_S3C2410)||defined(CONFIG_VIDEO_S3C2440)
#include <video_fb.h>
#include <asm/arch/s3c2410.h>
#include "videomodes.h"
/*
* Export Graphic Device
*/
static GraphicDevice smi;
#define VIDEO_MEM_SIZE 0x200000 /* 240x320x16bit = 0x25800 bytes */
extern void board_video_init( GraphicDevice *pGD);
/*
* Add by yanghao
*/
/*******************************************************************************
*
* Init video chip with common Linux graphic modes (lilo)
*/
void *video_hw_init (void)
{
struct s3c24x0_lcd * const lcd = s3c24x0_get_base_lcd();
GraphicDevice *pGD = (GraphicDevice *)&smi;
int videomode;
unsigned long t1, hsynch, vsynch;
char *penv;
int tmp, i, bits_per_pixel;
struct ctfb_res_modes *res_mode;
struct ctfb_res_modes var_mode;
// unsigned char videoout;
/* Search for video chip */
printf("Video: ");
tmp = 0;
videomode = CONFIG_SYS_DEFAULT_VIDEO_MODE;
/* get video mode via environment */
if ((penv = getenv ("videomode")) != NULL) {
/* deceide if it is a string */
if (penv[0] <= '9') {
videomode = (int) simple_strtoul (penv, NULL, 16);
tmp = 1;
}
} else {
tmp = 1;
}
if (tmp) {
/* parameter are vesa modes */
/* search params */
for (i = 0; i < VESA_MODES_COUNT; i++) {
if (vesa_modes[i].vesanr == videomode)
break;
}
if (i == VESA_MODES_COUNT) {
printf ("no VESA Mode found, switching to mode 0x%x ", CONFIG_SYS_DEFAULT_VIDEO_MODE);
i = 0;
}
res_mode =
(struct ctfb_res_modes *) &res_mode_init[vesa_modes[i].
resindex];
bits_per_pixel = vesa_modes[i].bits_per_pixel;
} else {
res_mode = (struct ctfb_res_modes *) &var_mode;
bits_per_pixel = video_get_params (res_mode, penv);
}
/* calculate hsynch and vsynch freq (info only) */
t1 = (res_mode->left_margin + res_mode->xres +
res_mode->right_margin + res_mode->hsync_len) / 8;
t1 *= 8;
t1 *= res_mode->pixclock;
t1 /= 1000;
hsynch = 1000000000L / t1;
t1 *=
(res_mode->upper_margin + res_mode->yres +
res_mode->lower_margin + res_mode->vsync_len);
t1 /= 1000;
vsynch = 1000000000L / t1;
/* fill in Graphic device struct */
sprintf (pGD->modeIdent, "%dx%dx%d %ldkHz %ldHz", res_mode->xres,
res_mode->yres, bits_per_pixel, (hsynch / 1000),
(vsynch / 1000));
printf ("%s\n", pGD->modeIdent);
pGD->winSizeX = res_mode->xres;
pGD->winSizeY = res_mode->yres;
pGD->plnSizeX = res_mode->xres;
pGD->plnSizeY = res_mode->yres;
switch (bits_per_pixel) {
case 8:
pGD->gdfBytesPP = 1;
pGD->gdfIndex = GDF__8BIT_INDEX;
break;
case 15:
pGD->gdfBytesPP = 2;
pGD->gdfIndex = GDF_15BIT_555RGB;
break;
case 16:
pGD->gdfBytesPP = 2;
pGD->gdfIndex = GDF_16BIT_565RGB;
break;
case 24:
pGD->gdfBytesPP = 3;
pGD->gdfIndex = GDF_24BIT_888RGB;
break;
}
/* statically configure settings */
pGD->winSizeX = pGD->plnSizeX = 320;
pGD->winSizeY = pGD->plnSizeY = 240;
pGD->gdfBytesPP = 2;
pGD->gdfIndex = GDF_16BIT_565RGB;
pGD->frameAdrs = LCD_VIDEO_ADDR;
pGD->memSize = VIDEO_MEM_SIZE;
board_video_init(pGD);
lcd->LCDSADDR1 = pGD->frameAdrs >> 1;
/* This marks the end of the frame buffer. */
lcd->LCDSADDR2 = (lcd->LCDSADDR1&0x1fffff) + (pGD->winSizeX+0) * pGD->winSizeY;
lcd->LCDSADDR3 = (pGD->winSizeX & 0x7ff);
/* Clear video memory */
memset((void *)pGD->frameAdrs, 0, pGD->memSize);
/* Enable Display */
lcd->LCDCON1 |= 0x01; /* ENVID = 1 */
return ((void*)&smi);
}
#endif /* CONFIG_VIDEO_S3C2410 */
修改driver/video/videomodes.h文件第25行左右为：
#ifndef CONFIG_SYS_DEFAULT_VIDEO_MODE
//#define CONFIG_SYS_DEFAULT_VIDEO_MODE 0x301
#define CONFIG_SYS_DEFAULT_VIDEO_MODE 0x211
#endif
紧接着修改driver/video/videomodes.h第81行左右为：
#define RES_MODE_1280x1024 5
#define RES_MODE_240x320 6
#define RES_MODES_COUNT 7
#define VESA_MODES_COUNT 20
在driver/video/videomodes..c文件struct ctfb_vesa_modes vesa_modes定义中添加（第78行左右）本开发板LCD的相关配置：
{0x211, RES_MODE_240x320, 16},
在driver/video/videomodes..c文件struct ctfb_res_modes res_mode_init定义中添加（第100行左右）本开发板LCD的相关配置：
{320, 240, 158025, 58, 15, 3, 5, 8, 15, 0, FB_VMODE_NONINTERLACED},
紧接着修改driver/video/Makefile文件，在41行后添加：
COBJS-$(CONFIG_VIDEO_S3C2440) += videomodes.o
COBJS-$(CONFIG_VIDEO_S3C2440) += s3c2410_fb.o
最后，修改文件board/fl2440/fl2440.c，在文件最后添加：
/*
* Add by yanghao
*/
#if defined(CONFIG_VIDEO_S3C2440)
#define MVAL (13)
#define MVAL_USED (0)
#define INVVDEN (1)
#define BSWP (0)
#define HWSWP (1)
//TFT 240320
#define LCD_XSIZE_TFT_240320 (320)
#define LCD_YSIZE_TFT_240320 (240)
//TFT 240320
#define HOZVAL_TFT_240320 (LCD_XSIZE_TFT_240320-1)
#define LINEVAL_TFT_240320 (LCD_YSIZE_TFT_240320-1)
//Timing parameter for WXCAT35-TG#001
#define VBPD_240320 (3)
#define VFPD_240320 (5)
#define VSPW_240320 (15)
#define HBPD_240320 (58)
#define HFPD_240320 (15)
#define HSPW_240320_WXCAT35 (8)//adjust the horizontal displacement of the screen
#define CLKVAL_TFT_240320 (7)
//FCLK = 405MHZ, HCLK = 101.25MHZ, VCLK=4602272HZ
void board_video_init(GraphicDevice *pGD)
{
struct s3c24x0_lcd * const lcd = s3c24x0_get_base_lcd();
/*Configuration for fl2440*/
lcd->LCDCON1 = (CLKVAL_TFT_240320 <<8)|(MVAL_USED <<7)|(3<<5)|(12<<1)|0;
lcd->LCDCON2 = (VBPD_240320<<24)|(LINEVAL_TFT_240320<<14)|(VFPD_240320<<6)|(VSPW_240320);
lcd->LCDCON3 = (HBPD_240320<<19)|(HOZVAL_TFT_240320<<8)|(HFPD_240320);
lcd->LCDCON4 = (MVAL<<8)|(HSPW_240320_WXCAT35);
lcd->LCDCON5 = (1<<11)|(1<<9)|(1<<8)|(1<<3)|(BSWP<<1)|(HWSWP);
lcd->LPCSEL = 0x00000000;
}
#endif /*CONFIG_VIDEO_S3C2440*/
最后还需要在开发板配置文件中添加LCD屏支持的宏定义，修改文件include/configs/fl2440.h文件，在文件中添加：
#include <video_fb.h> //头文件定义处添加
/*****************add by yanghao support LCD文件末尾处添加********************//*LCD support*/#define CONFIG_VIDEO_S3C2440 1#define CONFIG_VIDEO_LOGO 1#define CONFIG_VIDEO_BMP_LOGO 1#define VIDEO_FB_16BPP_WORD_SWAP 1#define CONFIG_CMD_BMP 1//#define CONFIG_LCD 1#define CONFIG_VIDEO 1#define CONFIG_CFB_CONSOLE 1#define CFG_CONSOLE_INFO_QUIET //support display of console information at boot#define LCD_VIDEO_ADDR 0x33b00000/*for PC-keyboard*/#define VIDEO_KBD_INIT_FCT 0/*for PC-keyboard*/#define VIDEO_TSTC_FCT serial_tstc#define VIDEO_GETC_FCT serial_getc#define CONFIG_SERIAL_MULTI 1/*LCD support*/
重新上电后，uboot的输出就都显示在LCD上了，我们的输入还是选择的串口输入，输入信息也都显示在LCD屏之上效果图如下：
