st7920 c语言驱动程序.txt

常用液晶模块选型资料及中文数据手册

/*=====================================================================
File name:  ST7920.c
Description:This is a test programm to diver ST7920.The interface between
            MCU and LCM is in parallel mode(Only write dat is available).
            Pin assignment :
            1--VSS;2--VDD;3--V0;4--R/S(CS)--P7.0;5--R/W(SID)--P7.1;
            6--E(SCLK)--P7.2;7-14--DB0-DB7--P6;15--PSB--P7.3;
            16--NC--P7.4;17--/RST--P7.5;18--VEE;19--LEDA;20--LEDK  
            
            RS     RW                  Description
            0       0                  MPU write instruction to IR(ST7920)
            0       1                  MPU read BF and AC(address counter)
            1       0                  MPU write data to DR(data register)
            1       1                  MPU read dat from DR          

Version: 1.0
date :   5,10  2005 (M-D-Y)
========================================================================*/


#include <C8051F040.H>  
#include <intrins.h>


#define  uchar   unsigned char
#define  uint   unsigned int

//define connection between MCU and ST7920
sbit ST7920RW=P7^1;     //Pin 5
sbit ST7920RS=P7^0;     //Pin 4
sbit ST7920CS=P7^6;     //Pin 6


//=================== prototype list =============================

void ST7920_Delay1ms(uchar n);       //to delay 1 ms about
void ST7920_SendCmd(uchar cmd);     //write command to ST7920
void ST7920_SendData(uchar dat);   //write dat to ST7920
void ST7920_Configuration(void);
void ST7920_Init(void);          //Initialize  ST7920

//================================================================


void main(void)
{
    uchar *chara="我爱你！";
    uchar *date="5-11-2005";
    uchar i;
    ST7920_Configuration();
    ST7920_Init();
    ST7920_SendCmd(0x80);
    ST7920_SendData('I');
    ST7920_SendCmd(0x81);
    ST7920_SendData('l');
    ST7920_SendData('o');
    ST7920_SendData('v');
    ST7920_SendData('e');
    ST7920_SendData('!');

          
    ST7920_SendCmd(0x90);
    for(i=0;i<4;i++)
    {       
             
        ST7920_SendData(*chara++);
        ST7920_SendData(*chara++);
        
    }  
    ST7920_SendCmd(0x88);
    /*while(*date!='\0')
    {
        ST7920_SendData(*date);
        date++;
    }  */
    for(;*date!='\0';date++)
    ST7920_SendData(*date);  
    while(1);       
}


//================================================================
void ST7920_Delay1ms(uchar n)
{
    uchar i;
    uchar j;
    for(j=0;j<n;j++)
    for(i=0;i<255;i++);
}

//================================================================
void ST7920_SendCmd(unsigned char cmd)
{
    EA=0;
    SFRPAGE=0x0f;
    P6=cmd;
    ST7920RS=0;
    ST7920RW=0;
    ST7920CS=1;
    _nop_();
    ST7920CS=0;
    _nop_();
    ST7920CS=1;
    _nop_();
    ST7920RW=1;
    P6=0xff;            
    ST7920RS=0;
    while(P6&0x80);     //make sure ST7920 is not in busy state by reading BF
    ST7920CS=0;
    ST7920CS=1;
    EA=1;
    // if(cmd)
    // ST7920_Delay1ms(3);
}
    

//================================================================
void ST7920_SendData(unsigned char dat)
{
    EA=0;
    SFRPAGE=0x0f;
    P6=dat;
    ST7920RS=1;
    ST7920RW=0;
    ST7920CS=1;
    ST7920CS=0;
    ST7920CS=1;
    ST7920RW=1;
    P6=0xff;            
    ST7920RS=0;
    while(P6&0x80);     //if BF(busy flag) is '1',wait 
    ST7920CS=0;
    ST7920CS=1;
    EA=1;
}  


//================================================================
//must be excuted ST7920_Init() firstly when reset the system

void ST7920_Init(void)  
{
    ST7920_Delay1ms(200);         //waiting
    ST7920_SendCmd(0x30);        //function set :8-bit interface
    ST7920_Delay1ms(10);
    ST7920_SendCmd(0x30);       //basic instruction
    ST7920_Delay1ms(10);
    ST7920_SendCmd(0x0c);      //display on,cursor off,blink off
    ST7920_Delay1ms(0x100);
    ST7920_SendCmd(0x01);     //display clear
    ST7920_Delay1ms(100);
    ST7920_SendCmd(0x06);    //cursor move right AC increased by 1,display not shift
    ST7920_Delay1ms(100);
}


//==================================================================
void ST7920_Configuration(void)
{
    WDTCN=0x07;
    WDTCN=0xde;
    WDTCN=0xad;   //disable watchdog       
   
    P6MDOUT=0x00;  // P6 is configured in Open-Drain mode
    P7MDOUT=0x0f; 
    
    SFRPAGE=0x0f;
    CLKSEL=0x00;       //   select internal oscillator  
    OSCXCN=0x00;      //  disable external oscillator 
    OSCICN=0x80;     // system clock derived from internal oscillator(24.5MHZ) devided by 8 
}