STM32F103带RA8871M，显示单张图片变成填充的问题。

qq812126060

用RA8871M驱动4.3寸（480*272）液晶屏，初始化配置显示480*272图片正常，但是显示100*100就变成平铺模式。是8871中的哪个寄存器没有配置好？求指点。
部分代码：
//画布配置

LCD_CanvasStructure.Address = 0x001C0000;      
  LCD_CanvasStructure.Width = 100;
  LCD_CanvasStructure.X_Coordinates = 0;  
  LCD_CanvasStructure.Y_Coordinates = 0;  
  LCD_CanvasStructure.Active_Width = 100;  
  LCD_CanvasStructure.Active_Height = 100;
  LCD_CanvasStructure.Mode = LCD_CANVAS_MODE_BLOCK;  
  LCD_CanvasStructure.ColorDepth = LCD_BLOCKMODE_COLORDEEP_16BPP;


//主显示配置
LCD_MainWindowsStructure.Address = 0x001C0000;      
  LCD_MainWindowsStructure.Width = 100;
  LCD_MainWindowsStructure.X_Coordinates = 0;  
  LCD_MainWindowsStructure.Y_Coordinates = 0;   
  LCD_MainWindowsStructure.ColorDepth = LCD_MAINWINDOWS_COLORDEEP_16BPP;