osd.c

这是一个7"LCD 液晶屏显示器

#include "indash.h"

extern          char    Current_Status;

void OSD_Clk()
{
   /* clock period > 4uS */
   OSD_SCL = 1;
   OSD_SCL = 1;
   OSD_SCL = 1;
   OSD_SCL = 1;
   OSD_SCL = 1;
   OSD_SCL = 1;
   OSD_SCL = 1;
   OSD_SCL = 1;
   OSD_SCL = 1;
   OSD_SCL = 1;
   OSD_SCL = 1;
   OSD_SCL = 0;
   OSD_SCL = 0;
}

void OSD_Transmit_Byte(unsigned char value) reentrant
{
   static char cnt = 0;

   cnt++;
   if (cnt < 8)
      OSD_Transmit_Byte(value / 2);
   else
      cnt = 0;

   OSD_SDA = value % 2;
   OSD_Clk();
}

void OSD_Ack_Bit()
{
   OSD_SDA = 1;
   OSD_Clk();
}

void OSD_Init(void)
{
/*
   unsigned int i,j;
*/

   OSD_Set( 0x129, 0x3158);
   OSD_Set( 0x120, 0x0580);
   OSD_Set( 0x121, 0x2c2b);
   OSD_Set( 0x122, 0x0bf);
   OSD_Set( 0x123, 0x180);//Horizontal display start location
   OSD_Set( 0x124, 0x20); //Vertical display start location
   OSD_Set( 0x125, 0);
   OSD_Set( 0x126, 0x0);
   OSD_Set( 0x127, 0x0);
   OSD_Set( 0x128, 0x2824);
/*
   for (i = 0; i < 250; i++)
   {
      j++;
      if (j > 7)
         j = 0;
      OSD_Set( i, 0x6000 | (j << 8) | i);
   }
   OSD_Set( 0x129, 0x1d40);
   Delay(1000);
*/

}

void OSD_Set(unsigned int addr, unsigned int value)
{
   /* start bit */
   OSD_SDA = 0;
   OSD_SCL = 0;

   /* control byte */
   OSD_Transmit_Byte(0x7c);
   OSD_Ack_Bit();

   /* address byte */
   OSD_Transmit_Byte(addr % 256);
   OSD_Ack_Bit();

   /* address byte */
   OSD_Transmit_Byte(addr / 256);
   OSD_Ack_Bit();

   /* data byte */
   OSD_Transmit_Byte(value % 256);
   OSD_Ack_Bit();

   /* data byte */
   OSD_Transmit_Byte(value / 256);
   OSD_Ack_Bit();

   /* stop bit */
   OSD_SDA = 0;

   /* very important */
   OSD_SCL = 1;

   OSD_SDA = 1;
}