drive_functions.h

单片机AT89C51扩展32KSRAM程序

#define uchar unsigned char
#define uint unsigned int
#define DI 	P03
#define RW 	P04
#define CS1 P05
#define CS2 P06
#define E 	P07
uchar chip_select=1;
uchar color=0x00;
bit black_flag=0;  //黑屏显示标志位
sbit P03=P0^3;
sbit P04=P0^4;
sbit P05=P0^5;
sbit P06=P0^6;
sbit P07=P0^7;
sbit P30=P3^0;
sbit P31=P3^1;
sbit P27=P2^7;
bit busy_bit=1;
bit menu=0;
uchar line=0;
uchar select=0;
#define LCD P1
/*************************** check busy ************************/

bit CheckBusy(void)
{
	uchar state=0;

	LCD=0xFF;
	RW=1;
	DI=0;
	E=1;
	E=0;
	E=1;        //E的下降沿，然后E持续拉高读才有效
	state=LCD;
	E=0;
	busy_bit=(bit)(state>>7);
	
	return(busy_bit);
	}


/************************* set display page ****************/ 

void SetPage(uchar page)
{	
	CS1=1;
	CS2=0;
	while(CheckBusy());
	LCD=0xFF;
	RW=0;
	DI=0;
	LCD=page+0xB8;
	E=1;
	E=0;

	CS1=0;
	CS2=1;
	while(CheckBusy());
	LCD=0xFF;
	RW=0;
	DI=0;
	LCD=page+0xB8;
	E=1;
	E=0;
	}

/************************ set display column *****************/

void SetColumn(uchar column)
{
	CS1=1;
	CS2=0;
	while(CheckBusy());
	LCD=0xFF;
	RW=0;
	DI=0;
	LCD=column+0x40;
	E=1;
	E=0;

	CS1=0;
	CS2=1;
	while(CheckBusy());
	LCD=0xFF;
	RW=0;
	DI=0;
	LCD=column+0x40;
	E=1;
	E=0;
	}


/***************************** write data ************************/

void WriteData(uchar dsp_data)
{
	while(CheckBusy());
	LCD=0xFF;
	if(chip_select==1)
	{
		CS1=1;
		CS2=0;
		}
	 else{
			CS1=0;
			CS2=1;
			}
	RW=0;
	DI=1;
	
	LCD=dsp_data;
	E=1;
	E=0;
	}

/**************************** read data ***********************/

uchar ReadData(void)
{
	uchar dsp_data;
	while(CheckBusy());
	LCD=0xFF;
	if(chip_select==1)
	{
		CS2=0;
		CS1=1;
		}
	 else{
	 		CS2=1;
			CS1=0;
			}
	RW=1;
	DI=1;
	E=1;
	E=0;
	E=1;        //E的下降沿，然后E持续拉高读才有效

	dsp_data=LCD;

	E=0;
	return(dsp_data);
	}

/******************** clear LCD *******************************/

void ClearLCD(void)
{
	uchar page,column;
if(black_flag==1)color=0xFF;   //设置清屏颜色
else color=0x00;
	for(page=0;page<8;page++)
	{
	  SetPage(page);
	  SetColumn(0);
	  for(column=0;column<64;column++)
	  {	 
		chip_select=1;   
		WriteData(color);               //clear chip1
		chip_select=2;                  
		WriteData(color);               //clear chip2
		}
	   }
	  }