WinCE的LCD驱动程序编写指南

本文以1024*768分辨率的TFT_16BPP真彩LCD为例,说明在WIN CE 4.2中驱动程序的修改事项，目标板的微处理器是S3C2410A。

 

该LCD的时序图如下图所示：

 

Note：LCD时序的参数和时钟相位因不同LCD而异,请参考相应LCD的datasheet.

在WIN CE 4.2中修改LCD驱动程序有五个相关文件,分别是：
1.    …/WINCE420/PLATFORM/SMDK2410/INC/s2410.h
2.    …/WINCE420/PLATFORM/SMDK2410/KERNEL/HAL/cfw.c
3.    …/WINCE420/PLATFORM/SMDK2410/DRIVERS/DISPLAY/S3C2410LCD/s3c2410disp.cpp
4.    …/WINCE420/PLATFORM/SMDK2410/FILES/config.bib
5.    …/ WINCE420/PLATFORM/SMDK2410/FILES/platform.reg

 

1.  s2410.h
…/WINCE420/PLATFORM/SMDK2410/INC/s2410.h
主要有 LCD 控制器的寄存器定义、 LCD 控制器的工作时序定义、分辨率的定义等等。红色部分为修改后的内容：
#define LCDTYPE                       TFT16BPP
#define LCD_TYPE                     TFTxxx_xxx

#define SCR_XSIZE_TFT            (1280)
#define SCR_YSIZE_TFT            (960)
#define LCD_XSIZE_TFT           (1024)
#define LCD_YSIZE_TFT            (768)

#define VBPD                            ((2-1)&0xff)
#define VFPD                            ((2-1)&0xff)
#define VSPW                           ((2-1) &0x3f)
#define HBPD                            ((16-1)&0x7f)
#define HFPD                            ((200-1)&0xff)
#define HSPW                           ((16-1)&0xff)
#define CLKVAL_TFT               (1)   // 这个值的定义在 LCD 初始化函数中并不用到 , 而是直接用数值表示。



2.  cfw.c
…/WINCE420/PLATFORM/SMDK2410/KERNEL/HAL/cfw.c
红色部分为修改后的内容：
static void InitDisplay()
{
       ********
       s2410LCD->rLCDCON1=(1<<8)|(MVAL_USED<<7)|(3<<5)|(12<<1)|0;
                                              // CLKVAL_TFT = 1 , HCLK = 100MHz -> VCLK = 25MHz
                                                                                     // TFT LCD panel
                                                                                                //16 bpp for TFT
       s2410LCD->rLCDCON2=(VBPD<<24)|(LINEVAL_TFT<<14)|(VFPD<<6)|(VSPW);
       s2410LCD->rLCDCON3=(HBPD<<19)|(HOZVAL_TFT<<8)|(HFPD);
       s2410LCD->rLCDCON4=(MVAL<<8)|(HSPW);
       s2410LCD->rLCDCON5=
       (1<<11)|(0<<10)|(0<<9)|(0<<8)|(0<<7)|(0<<6)|(0<<3)|(0<<1)|(1<<0);
        // 5:6:5 Format
        //The video data is fetched at VCLK falling edge
        //VLINE/HSYNC pulse polarity-Normal
        //VFRAME/VSYNC pulse polarity-Normal
        //VD (video data) pulse polarity-Normal
        //VDEN signal polarity-Normal
        //Disable PWREN signal
        //Byte swap Disable
        //Half-Word swap Enable
       ********
}

  红色部分为修改后的内容：

WORD    TempBuffer[1025][768];
S3C2410DISP::S3C2410DISP (void)
{
       ********
       m_nScreenWidth = 1024;
       m_nScreenHeight = 768;
       *********
}

       到此修改工作基本完成，但还要一个问题： 1024*768 分辨率占用的显示缓冲区大小是： 1024*768*2 = 1536 K Bytes, 因此要确认所分配的内存空间够不够 , 是在 config.bib 文件中定义的。如果以前定义的足够大 , 后面的步骤可以省略了。

 

4.  config.bib
…/WINCE420/PLATFORM/SMDK2410/FILES/config.bib
       #define NKNAME NK
       #define NKSTART         8C200000
       #define NKLEN              01D00000
       #define RAMSTART      8E000000
       #define RAMLEN           01F00000
       $(NKNAME)              $(NKSTART)        $(NKLEN)            RAMIMAGE
       RAM                         $(RAMSTART)      $(RAMLEN)        RAM
       AUD_DMA                  8c002000             00002000             RESERVED
       DRV_GLB                   8c010000             00010000             RESERVED
       DBGSER_DMA            8c022000             00002000             RESERVED
       SER_DMA                   8c024000             00002000             RESERVED
       IR_DMA                     8c026000             00002000             RESERVED
       SD_DMA                    8c028000             00008000             RESERVED
       EDBG                         8c030000             00020000             RESERVED
       CPXIPCHAIN              8c050000             00008000             RESERVED
       SLEEP_BUFF              8c058000             00004000             RESERVED
       DISPLAY                    8c100000             00100000             RESERVED



       DISPLAY

       AUD_DMA                 8c002000             00002000             RESERVED
       DRV_GLB                  8c010000             00010000             RESERVED
       DBGSER_DMA           8c022000            00002000              RESERVED
       SER_DMA                 8c024000             00002000              RESERVED
       IR_DMA                    8c026000             00002000              RESERVED
       SD_DMA                   8c028000             00008000             RESERVED
       EDBG                        8c030000             00020000             RESERVED
       CPXIPCHAIN             8c050000             00008000             RESERVED
       SLEEP_BUFF              8c058000              00004000              RESERVED
       ;DISPLAY                   8c100000              00100000              RESERVED
        DISPLAY                    8c 060000              001a 0000              RESERVED

 

 

5.  

在（4）中修改了DISPLAY显示缓冲区的开始地址,因此要在“s2410.h”中做相应的修改：
…/WINCE420/PLATFORM/SMDK2410/INC/s2410.h
#define DMA_BUFFER_BASE                    0xAC000000
#define DMA_PHYSICAL_BASE                0x30000000

//#define FRAMEBUF_BASE                      (DMA_BUFFER_BASE + 0x00100000)
//#define FRAMEBUF_DMA_BASE             (DMA_PHYSICAL_BASE + 0x00100000)
#define FRAMEBUF_BASE                        (DMA_BUFFER_BASE + 0x00060000)
#define FRAMEBUF_DMA_BASE               (DMA_PHYSICAL_BASE + 0x00060000)



6.  在（4）中修改了DISPLAY显示缓冲区的大小, 因此要在“s3c2410disp.cpp”中做相应的修改：
       …/WINCE420/PLATFORM/SMDK2410/DRIVERS/DISPLAY/S3C2410LCD/s3c2410disp.cpp
红色部分为修改后的内容：

void S3C2410DISP::InitializeHardware (void)
{
       *********
       m_VirtualFrameBuffer = (DWORD)VirtualAlloc(0, (0x1A0000), MEM_RESERVE, PAGE_NOACCESS);
       if (m_VirtualFrameBuffer == NULL)
       {
           RETAILMSG(0,(TEXT("m_VirtualFrameBuffer is not allocated/n/r")));
              return;
       }
       else if (!VirtualCopy((PVOID)m_VirtualFrameBuffer, (PVOID)gdwLCDVirtualFrameBase, (0x1A0000), PAGE_READWRITE | PAGE_NOCACHE))
       {
           RETAILMSG(0, (TEXT("m_VirtualFrameBuffer is not mapped/n/r")));
           VirtualFree((PVOID)m_VirtualFrameBuffer, 0, MEM_RELEASE);
           return;
       }
       *********
}

 

7. 

 

 

完！