m128的特點是io口很多，所以我們可以用并行的方式來驅動此液晶屏，增加總線的速度，此程序是是網上整理收集而來，但已經通過本人驗證可以使用，故在此發表.大家在應用的時候只需更改相應的io就行了.
軟件：GCC V4.20
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實驗內容：寫Lcd12864_ST7920。
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硬件連接：
LCD12864_ST7920 ATmega128
1.GND -------- GND
2.VCC -------- VCC
3.V0 -------- NC
4.RS(CS) -------- PD7
5.R/W(SID) -------- PG0
6.E(SCLK) -------- PG1
7.D0 -------- PC0
8.D1 -------- PC1
9.D2 -------- PC2
10.D3 -------- PC3
11.D4 -------- PC4
12.D5 -------- PC5
13.D6 -------- PC6
14.D7 -------- PC7
15.PSB -------- VCC
16.NC -------- NC
17.RST -------- VCC
18.NC -------- NC
19.LED+ -------- VCC
20.LED- -------- GND
以下是程序源代碼：
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#include <avr/io.h>
#include<avr/pgmspace.h>
#include <util/delay.h>
#define E_set PORTG|=_BV(PG1) //液晶使能
#define E_clear PORTG&=~_BV(PG1)
#define RW_set PORTG|=_BV(PG0) //液晶讀寫
#define RW_clear PORTG&=~_BV(PG0)
#define RS_set PORTD|=_BV(PD7) //液晶數據
#define RS_clear PORTD&=~_BV(PD7) //液晶指令
unsigned char j=0;
unsigned char yb=0x80;
unsigned char name00[] PROGMEM={"飛射白鹿雪連天，"};
unsigned char name01[] PROGMEM={"笑書神俠倚碧鴛。"};
unsigned char name02[] PROGMEM={"自古英雄多奇逸，"};
unsigned char name03[] PROGMEM={"金老揮毫盡使然。"};
unsigned char name10[] PROGMEM={"李白乘舟將欲行，"};
unsigned char name11[] PROGMEM={"忽聞岸上踏歌聲。"};
unsigned char name12[] PROGMEM={"桃花潭水深千尺，"};
unsigned char name13[] PROGMEM={"不及汪倫送我情。"};
unsigned char name20[] PROGMEM={"this is a 12864 "};
unsigned char name21[] PROGMEM={"display program,"};
unsigned char name22[] PROGMEM={"welcome to commu"};
unsigned char name23[] PROGMEM={"nicate with me! "};
void wr_com(unsigned char);
void wr_data(unsigned char);
void reset (void);
void outChinese(unsigned char,unsigned char,unsigned char *point);
void ydgb(void);
void outchar(unsigned char,unsigned char,unsigned char *point);
void wr_com(unsigned char value)//寫指令，寫指令時必須為RS=0;RW=0;
{
E_clear;
RS_clear;
RW_clear;
_delay_ms(1);
PORTC=value; //并入字符數據
E_set;
_delay_ms(2); //如果沒有延時就必須要加查忙指令
E_clear;
}
void wr_data(unsigned char sj)//寫數據，寫數據時必須為 RS=1;RW=0;
{
E_clear;
RS_set;
RW_clear;
_delay_ms(1);
PORTC=sj;
E_set;
_delay_ms(1);//如果沒有延時就必須要加查忙指令
E_clear;
}
void reset (void)
{
wr_com(0x01);//清屏
wr_com(0x08);//關顯示
wr_com(0x03);//歸位
wr_com(0x30);//功能設置
wr_com(0x0f);//開顯示
wr_com(0x01);//清屏
}
//****************
//outChinese 為函數名
//place 為顯示地址的首地址
//unit 字符長度
//charcode[] 要顯示數據的內容
void outChinese(unsigned char place,unsigned char unit,unsigned char *point)
{
unsigned char i,progdata;
wr_com(place);
for(i=0;i<unit*2;i++)//一個漢字為兩個字符
{
progdata=pgm_read_byte(point+i);
wr_data(progdata);
}
}
void outchar(unsigned char place,unsigned char unit,unsigned char *point)
{
unsigned char i,progdata;
wr_com(place);
for(i=0;i<unit;i++)
{
progdata=pgm_read_byte(point+i);
wr_data(progdata);
}
}
void ydgb(void)
{
wr_com(yb);//顯示光標位置
yb=yb+0x01;
if(yb==0x88){yb=0x90;}
if(yb==0x97){yb=0x88;}
if(yb==0x8f){yb=0x98;}
if(yb==0xa0){yb=0x80;}
}
void display1(void)
{
ydgb();
outChinese(0x80,8,name00);//第一行：80-87H
outChinese(0x90,8,name01);//第二行：90-97H
outChinese(0x88,8,name02);//第三行：88-8FH
outChinese(0x98,8,name03);//第四行：98-9FH
//outchar(0x9f,2,name4);
}
void display2(void)
{
ydgb();
outChinese(0x80,8,name10);
outChinese(0x90,8,name11);
outChinese(0x88,8,name12);
outChinese(0x98,8,name13);
}
void display3(void)
{
ydgb();
outchar(0x80,16,name20);
outchar(0x90,16,name21);
outchar(0x88,16,name22);
outchar(0x98,16,name23);
}
int main(void)
{
DDRC=0xff; //數據
PORTC=0x00;
DDRG=0xff; //命令
PORTG=0xff;
DDRD=0xff; //命令
PORTD=0xff;
reset();
while(1)
{
ydgb();
j++;
ydgb();
wr_com(0x01);//清屏
if(j==3)j=0;
switch(j)
{
case 0:display1();break;
case 1:display2();break;
case 2:display3();break;
}
_delay_ms(3000);
}
}