RK2706播放器printf定位到LCD

发布于 2011-10-21 22:17:04 浏览：9698 订阅该版

[attachment=-2]
看RM970原理图得知LCD中IM0 IM1 ID0都接上了GND,查LCD(控制器为SPFD5420A)得知,此时LCD工作于18bit,80-system.既为最常见的MCU接口.

所以配置RK2706来说是这么一个通用流程:
1.设置相应引脚为LCD功能
```c
void iomux_lcd(void)
{
   unsigned long muxa;

SCU_IOMUXA_CON = muxa;
   SCU_IOMUXB_CON |=

IOMUX_LCD_D815;
}
```

2.设置LCD寄存器,配置时序.
```c
void lcdctrl_init(void)
{
	/* alpha b111
	 * stop at current frame complete
	 * MCU mode
	 * 24b RGB
	 */
	LCDC_CTRL = ALPHA(7) | LCDC_STOP | LCDC_MCU | RGB24B;

MCU_CTRL = ALPHA_BASE(0x3f) | MCU_CTRL_BYPASS;

HOR_ACT = 400 + 3;    /* define horizonatal active region */

VERT_ACT = 240;       /* define vertical active region */

VERT_PERIOD = 0xfff;  /* CSn/WEn/RDn signal timings */

LINE0_YADDR = LINE_ALPHA_EN | 0x7fe;
	LINE1_YADDR = LINE_ALPHA_EN | ((1 * 400) - 2);
	LINE2_YADDR = LINE_ALPHA_EN | ((2 * 400) - 2);
	LINE3_YADDR = LINE_ALPHA_EN | ((3 * 400) - 2);
	LINE0_UVADDR = 0x7fe + 1;
	LINE1_UVADDR = ((1 * 400) - 2 + 1);
	LINE2_UVADDR = ((2 * 400) - 2 + 1);
	LINE3_UVADDR = ((3 * 400) - 2 + 1);

LCDC_INTR_MASK = INTR_MASK_LINE; /* INTR_MASK_EVENLINE; */
}
```

3.初始化LCD寄存器.
```c
void lcd_init_device()
{
  unsigned int x, y;
  iomux_lcd();       /* setup pins for 18bit lcd interface */
  lcdctrl_init();    /* basic lcdc module configuration */
  lcdctrl_bypass(1); /* run in bypass mode - all writes goes directly to lcd controller */

lcd_write_reg(RESET, 0x0001);
  delay_nop(10000);
  lcd_write_reg(RESET, 0x0000);
  delay_nop(10000);

lcd_write_reg(IF_ENDIAN,    0x0000); /* order of receiving data */
  lcd_write_reg(DRIVER_OUT_CTRL, 0x0000);
  lcd_write_reg(ENTRY_MODE,      0x1038);
  lcd_write_reg(WAVEFORM_CTRL,   0x0100); 
  lcd_write_reg(SHAPENING_CTRL,  0x0000);
  lcd_write_reg(DISPLAY_CTRL2,   0x0808);
  lcd_write_reg(LOW_PWR_CTRL1,   0x0001);
  lcd_write_reg(LOW_PWR_CTRL2,   0x0010);
  lcd_write_reg(EXT_DISP_CTRL1,  0x0000);
  lcd_write_reg(EXT_DISP_CTRL2,  0x0000);
  lcd_write_reg(BASE_IMG_SIZE,   0x3100);
  ......................
}
```

细心的朋友会发现这些寄存器初始值都为16bit,而LCD为18bit,所以得用下面函数转换成18bit后才能写给LCD.
```c
__inline unsigned int lcd_data_transform(unsigned int data)
{
    /* 18 bit interface */
    unsigned int r, g, b;

r = (data & 0x0000fc00)<<8;
    g = ((data & 0x00000300) << 6) | ((data & 0x000000e0) << 5);
    b = (data & 0x00000001f) << 3;

return (r | g | b);
}
```
初试化完毕后,一个不约而同的规则便是实现画横竖线与打点了.
```
/* 画水平线 */
void rt_hw_lcd_draw_hline(rtgui_color_t *c, rt_base_t x1, rt_base_t x2, rt_base_t y)
{

lcd_write_reg(WINDOW_H_START,  y);
    lcd_write_reg(WINDOW_H_END,    y);
    lcd_write_reg(WINDOW_V_START,  x1);
    lcd_write_reg(WINDOW_V_END,    x2);

lcd_write_reg(GRAM_H_ADDR,     y);
    lcd_write_reg(GRAM_V_ADDR,     x1);

lcd_cmd(GRAM_WRITE); /* Prepare to write GRAM */
    while (x1 < x2)
    {
        LCD_DATA = lcd_pixel_transform(*c);
        x1++;
    }
}

/* 垂直线 */
void rt_hw_lcd_draw_vline(rtgui_color_t *c, rt_base_t x, rt_base_t y1, rt_base_t y2)
{

lcd_write_reg(WINDOW_H_START,  y1);
    lcd_write_reg(WINDOW_H_END,    y2);
    lcd_write_reg(WINDOW_V_START,  x);
    lcd_write_reg(WINDOW_V_END,    x);

lcd_SetCursor(x, y1);
    lcd_cmd(GRAM_WRITE); /* Prepare to write GRAM */

while (y1 < y2)
    {
        LCD_DATA = lcd_pixel_transform(*c);
        y1++;
    }
}

/*  设置像素点 颜色,X,Y */
void rt_hw_lcd_set_pixel(rtgui_color_t *c, rt_base_t x, rt_base_t y)
{
    lcd_write_reg(WINDOW_H_START,  y);
    lcd_write_reg(WINDOW_H_END,    y);
    lcd_write_reg(WINDOW_V_START,  x);
    lcd_write_reg(WINDOW_V_END,    x);

lcd_SetCursor(x,y);

lcd_cmd(GRAM_WRITE);
    LCD_DATA = lcd_pixel_transform(*c);
}
```

注意这SPFD5420A打点函数与常见的控制器还不一样,还要设置窗口为此点.要不然会有些莫名奇妙的问题.(起码这边测试的是这样).
实现打点函数后便可以将printf定位到LCD了,新建Retarget.c文件,在里面实现fputc()函数
```c
int fputc(int ch, FILE *f) 
{
  int MaxX = 400 / 6;
  int MaxY = 240 / 12;
  int n;
 	
  if(ch != '
' && ch != '
' && ch != '�')
  {
        lcd_show_char(CurrentX*6, ((CurrentY + MaxY)%MaxY)*12, ch);
  }

CurrentX++;
  return 1;
}
```

这里并没考虑更多情况,请各位按需要自行改进.
最后顺便在rtthread.h加上:
```c
#define rt_kprintf printf
```
两个应该注意的地方.一是记得开背光,二是Options-Target-Use Micro LIB选项记得勾上,而且启动代码中Micro_Lib_Stack_Size宏大小最好相应改大.

如无意外printf,与rt_kprintf都已经定位到LCD了.
[attachment=-1]
附件为SPFD5420A数据手册
[attach]0[/attach] 
- [SPFD5420A.rar](uploads/2304_0a1912ad2c8c871f972447d3444fcac9.rar)

<br> 
![lcd.jpg](https://oss-club.rt-thread.org/uploads/2304_82c54a37b1bc2a2829fcc846db65fbc9.jpg)
 
<br> 
![lcd_printf.jpg](https://oss-club.rt-thread.org/uploads/2304_77e8cdd17a6c8701dc9b55ec9a26acfd.jpg)

<br> 
![截图5420.png](https://oss-club.rt-thread.org/uploads/3871_d4dd4923e99cfcaaa11e2e8794747e91.png)
 
<br> 
![数据转换.png](https://oss-club.rt-thread.org/uploads/3871_83c14b49f1fd62c1539d420c74aea4ab.png)