+ 图片显示

对于其它的开发板，若不借助SD卡要显示图片是较为困难，因为通常的MCU其程序存储空间是相对较小的，只能借助外部存储单元来存放图片数据。由于NUCLEO_F412ZGT6具有1 MB 闪存、256KB的SRAM，使用在存放程序之余是有空间来存放图像数据的。以一幅320*240像素的16位色彩的图片为例，它要占用153.6KB 的 存储空间，是完全可以将图像数据存放到程序的。

在NUCLEO_F412ZG开发板上，要显示图像的显示需要具备以下的条件：

1）具有相应的TFT显示屏来支持图像显示，为了有效地减少连线数量，这里是采用2.2寸的串行TFT屏来显示图像。

2）配有相应的工具软件来辅助进行图片的处理，主要处理的任务是裁剪图片使之符合TFT显示屏的尺寸规格及压缩图片的数据量，对于24位色的位图文件*.bmp，可以通过辅助工具将其转为16位色*.C文件，这样就可以在保证图像质量的情况下，是图像数据量缩减三分之一。

3）编写相应的TFT屏驱动程序及图像显示函数。

以显示图1的内容为例，为了适应TFT屏的显示形式需将图片旋转90度，使之成为纵向的放置的图片。然后再使用工具软件Image2Lcd v2.9来进行文件格式的转换，相关参数的设置下图所示。

所生成的数据文件其数据格式如下：

const unsigned char gImage_123[84960] = { /* 0X10,0X10,0X00,0XF0,0X00,0XB1,0X01,0X1B, */

0X6C,0X38,0X6C,0X59,0X6C,0X79,0X64,0X58,0X6C,0X99,0X6C,0X79,0X6C,0X79,0X6C,0X59,

0X6C,0X59,0X74,0X99,0X6C,0X59,0X74,0X99,0X6C,0X79,0X6C,0X59,0X6C,0X79,0X6C,0X79,

0X6C,0X79,0X6C,0X59,0X74,0X99,0X74,0X99,0X6C,0X79,0X74,0X99,0X74,0X99,0X74,0X9A,

0X74,0X9A,0X74,0X99,0X74,0X9A,0X74,0X9A,0X6C,0X79,0X74,0X9A,0X6C,0X99,0X74,0X9A,

0X6C,0X79,0X74,0X99,0X6C,0X99,0X74,0X9A,0X74,0XBA,0X74,0X99,0X74,0X99,0X74,0X9A,

0X74,0X99,0X74,0XBA,0X6C,0X99,0X74,0X99,0X74,0X99,0X74,0XBA,0X74,0XBA,0X74,0XB9,

0X74,0X99,0X74,0XBA,0X74,0X99,0X74,0XBA,0X74,0X99,0X74,0X99,0X74,0XBA,0X74,0X99,

0X74,0XBA,0X74,0XBA,0X74,0XBA,0X7C,0XDA,0X74,0XBA,0X74,0XB9,0X74,0XBA,0X74,0XBA,

0X74,0XBA,0X74,0XBA,0X7C,0XDA,0X74,0XDA,0X74,0XBA,0X74,0XBA,0X74,0XBA,0X74,0XBA,

0X7C,0XDA,0X7C,0XDA,0X7C,0XDA,0X7C,0XDA,0X7C,0XDA,0X74,0XB9,0X7C,0XDA,0X74,0XDA,

0X7C,0XDA,0X7C,0XDA,0X74,0XDA,0X74,0XDA,0X7C,0XFA,0X7C,0XDA,0X7C,0XDA,0X7C,0XFA,

0X7C,0XFB,0X7C,0XFA,0X7C,0XFA,0X74,0XDA,0X7C,0XFA,0X7C,0XFB,0X7C,0XDA,0X7C,0XFA,

0X7C,0XDA,0X7C,0XFA,0X7C,0XFB,0X7C,0XFA,0X7C,0XFA,0X7C,0XFA,0X7C,0XFA,0X7C,0XFA,

0X84,0XFA,0X84,0XFA,0X85,0X1A,0X85,0X1B,0X85,0X1A,0X85,0X1A,0X7C,0XFA,0X84,0XFA,

0X84,0XFA,0X85,0X1A,0X85,0X1A,0X85,0X1B,0X85,0X1A,0X85,0X3B,0X85,0X3B,0X85,0X3B,

0X85,0X3A,0X85,0X3B,0X85,0X3B,0X85,0X3B,0X85,0X3B,0X85,0X5B,0X85,0X3B,0X8D,0X5B,

0X85,0X3B,0X85,0X3B,0X8D,0X7C,0X8D,0X5B,0X8D,0X5B,0X95,0X9B,0X9D,0XDC,0XA5,0XBB,

0X9D,0X9B,0XA5,0XFC,0XAD,0XFC,0XB6,0X3C,0XB6,0X1C,0XAE,0X1C,0XAD,0XFC,0X9D,0XBC,

0X9D,0XBC,0X9D,0X9C,0X95,0X9C,0X95,0X9C,0X95,0X9C,0X9D,0XBC,0XAE,0X1D,0XBE,0X5D,

0XBE,0X7D,0XC6,0X7D,0XC6,0X9D,0XBE,0X9D,0XBE,0X5D,0XAE,0X1D,0XA5,0XDC,0X9D,0XDC,

0X9D,0XBC,0X9D,0XDC,0X9D,0XDC,0X9D,0XDC,0X9D,0XBC,0X9D,0XBC,0X9D,0XDC,0X9D,0XDC,

0XA5,0XFD,0XA5,0XDC,0XA5,0XFD,0XA5,0XFD,0XA5,0XFD,0XA6,0X1D,0XB6,0X3D,0XB6,0X5D,

0XB6,0X3D,0XBE,0X7D,0XBE,0X5D,0XBE,0X5D,0XBE,0X5D,0XBE,0X5D,0XBE,0X7D,0XBE,0X9D,

0XC6,0X9D,0XC6,0X9D,0XBE,0X9D,0XC6,0X9D,0XC6,0X9E,0XC6,0X7D,0XC6,0X9E,0XC6,0XBE,

0XC6,0XBD,0XCE,0XBD,0XCE,0XDE,0XD6,0XFE,0XD6,0XFE,0XDF,0X1E,0XDF,0X1E,0XDF,0X3E,

0XDF,0X3E,0XDF,0X3F,0XDF,0X3F,0XDF,0X3F,0XDF,0X3F,0XE7,0X5F,0XDF,0X3E,0XE7,0X5F,

0XE7,0X5F,0XE7,0X7F,0XE7,0X7F,0XE7,0X7F,0XE7,0X7F,0XE7,0X5F,0XDF,0X5F,0XDF,0X3F,。}

参数设置界面如上图所示。

就2.2寸串行TFT屏来讲，它共有9个引脚，其与开发板的连接关系如下：

CS --PB.4 SCK --PB.3 SDI --PB.5 DC --PB.1 REST --PB.0

向TFT屏输出高、低电平的语句定义如下：

#define LCD_CS_High() { HAL_GPIO_WritePin(GPIOB, GPIO_PIN_4, GPIO_PIN_SET);}

#define LCD_CS_Low() { HAL_GPIO_WritePin(GPIOB, GPIO_PIN_4, GPIO_PIN_RESET);}

#define LCD_SCK_High() { HAL_GPIO_WritePin(GPIOB, GPIO_PIN_3, GPIO_PIN_SET);}

#define LCD_SCK_Low() { HAL_GPIO_WritePin(GPIOB, GPIO_PIN_3, GPIO_PIN_RESET);}

#define LCD_SDI_High() { HAL_GPIO_WritePin(GPIOB, GPIO_PIN_5, GPIO_PIN_SET);}

#define LCD_SDI_Low() { HAL_GPIO_WritePin(GPIOB, GPIO_PIN_5, GPIO_PIN_RESET);}

#define LCD_DC_High() { HAL_GPIO_WritePin(GPIOB, GPIO_PIN_1, GPIO_PIN_SET);}

#define LCD_DC_Low() { HAL_GPIO_WritePin(GPIOB, GPIO_PIN_1, GPIO_PIN_RESET);}

#define LCD_REST_High() { HAL_GPIO_WritePin(GPIOB, GPIO_PIN_0, GPIO_PIN_SET);}

#define LCD_REST_Low() { HAL_GPIO_WritePin(GPIOB, GPIO_PIN_0, GPIO_PIN_RESET);}

配置GPIO引脚实现输入、输出的函数如下：

• static GPIO_InitTypeDef  GPIO_InitStruct;
  
• void GPIO_Configuration(void)
  
• {
  
•     __HAL_RCC_GPIOB_CLK_ENABLE();  
  
•   GPIO_InitStruct.Pin   = GPIO_PIN_4|GPIO_PIN_3|GPIO_PIN_5|GPIO_PIN_1|GPIO_PIN_0;
  
•   GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;   
  
•   GPIO_InitStruct.Mode  = GPIO_MODE_OUTPUT_PP;
  
•   GPIO_InitStruct.Pull  = GPIO_PULLUP;
  
•   HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
  
• }
  

• 实现图片显示的函数为：

  
  
• • void showimage(unsigned int x,unsigned int y)
    
  • {  
    
  •     unsigned int i,j,k;
    
  •     unsigned int da;
    
  •     k=0;
    
  •     for(i=0;i<320;i++)
    
  •     {   
    
  •         LCD_SetCursor(x,y+i);
    
  •         LCD_WriteRAM_Prepare();                     
    
  •         for(j=0;j<240;j++)
    
  •         {
    
  •             da=gImage_gq1[k*2];
    
  •             da<<=8;
    
  •             da|=gImage_gq1[k*2+1];
    
  •             LCD_WR_DATA(da);                    
    
  •             k++;   
    
  •         }
    
  •     }
    
  • }
    
  • 经编译和下载，程序的运行效果下图所示。
    
  • 
    
    
    
  • 
    
    
  
  

谢谢分享，学习学习。