lcd_main.c

ST7920并行方式的源码,自己写的,大家可以参考一下

#include <AT89X55.H>
#include <LCD.h>
#include <8255.h>
#include <ABSACC.H>








void ST7920_Init(void)
{	
	_8255_CS=0;

	PBYTE[_8255_Cortrol]= _8255_Init;
	_8255_CS=1;

	ST7920_WriteInstruction(ST7920_FUN_SET);
	
	ST7920_WriteInstruction(ST7920_CURSOR_Line);
	
	ST7920_WriteInstruction(ST7920_MODE_SET);
}












/*
***********************************************************************************************
*                                        Write Data RAM		
*
* Description: Write Data RAM
*
* Arguments  : Data value written to RAM
*
* Returns    : none
*
* Notes      : 1) 
***********************************************************************************************
*/

void ST7920_WriteData(unsigned char temp)
{
	unsigned char cDate;
	E12864=0;											//E=0
  	cDate=temp;	 
  	ST7920_RS=1;										//RS=1
	
	_8255_CS=0;
  	PBYTE[_8255_Cortrol]=PC_2_RST;						//RW=0
  	PBYTE[_8255_A]=cDate;								//Write date to Lcd
	_8255_CS=1;

  	E12864=1;											//E=1
	Delayl(0x1A);
}



















/*
***********************************************************************************************
*                                 Write Instruction Register		
*
* Description: Write Instruction Register
*
* Arguments  : Instruction value written to Instruction Register
*
* Returns    : none
*
* Notes      : 1)
***********************************************************************************************
*/

void ST7920_WriteInstruction(unsigned char temp)
{
	unsigned char cDate;
  	E12864=0;											//E=0
  	cDate=temp;										
  	ST7920_RS=0;										//RS=0

	_8255_CS=0;
  	PBYTE[_8255_Cortrol]=PC_2_RST;						//RW=0
  	PBYTE[_8255_A]=cDate;								//Write date to Lcd
	_8255_CS=1;

  	E12864=1;											//E=1
	Delayl(0x1A);
}




void  DspTitle(void)
{ 
 unsigned char Title[] = {"GSM/GPRS通信测试V1.01 2006年05月"
  				  "上海第二工业大学电子电气工程学院"};
  WriteOneScreen(0x0,64,Title);
}


















/*
***********************************************************************************************
*                                       	Write Line Data	
*
* Description: Write Data to Line (ST7920)
*
* Arguments  : startAddress		is the start address of the Line (80 ~ 9F)
*			   dataNum			is the number of data to be written to Line 
*			   dataVector		is a pointer to the header of the data vector
* Returns    : none
*
* Notes      : 1) MAY have problem while interrupts are being enabled
*			   2) data length is UP to 16 bytes	
*		
***********************************************************************************************
*/


  void ST7920_Write_Line (unsigned char startAddress, unsigned char dataNum, 
						  unsigned char *dataVector)
{
 	ST7920_WriteInstruction(startAddress);

    while(dataNum > 0)
    {
        ST7920_WriteData(*dataVector);
        dataNum--;
        dataVector++;
    }
}



















/*
***********************************************************************************************
*                                			Write Full Screen	
*
* Description: Write Full Screen (ST7920)
*
* Arguments  : startAddress		is the start address of the start (80 ~ 9F)
*			   dataNum			is the number of data to be written to Line (0~64)
*			   dataVector		is a pointer to the header of the data vector
*
* Returns    : none
*
* Notes      : 1) data length is UP to 16 bytes	
***********************************************************************************************
*/
	
 void WriteOneScreen(unsigned char startAddress, unsigned char dataNum,unsigned char *dataVector)
{
	unsigned char cLoop;
	
	cLoop = startAddress;
	
    while(dataNum > 0)
    {
        switch(cLoop)
        {
        	case 0x0:
        		ST7920_WriteInstruction(0x80);
        		break;
        	case 0x10:
        		ST7920_WriteInstruction(0x90);
        		break;
        	case 0x20:
        		ST7920_WriteInstruction(0x88);
        		break;
        	case 0x30:
        		ST7920_WriteInstruction(0x98);
        		break;		
        }
        cLoop=(cLoop+1)&0x3f;
        ST7920_WriteData(*dataVector);
        dataNum--;
        dataVector++; 	
    }
}

void Delayl(unsigned int time)
{
	while (time > 0)time--;
}