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13.2 1602整屏移動(dòng) 我們前邊學(xué)第七章點(diǎn)陣LED的時(shí)候，可以實(shí)現(xiàn)上下移動(dòng)，左右移動(dòng)等。而對(duì)于1602液晶來(lái)說(shuō)，也可以進(jìn)行屏幕移動(dòng)，實(shí)現(xiàn)我們想要的一些效果，那我們來(lái)用一個(gè)例程實(shí)現(xiàn)字符串在1602液晶上的左移。每個(gè)人都不要只瞪著眼看，一定要認(rèn)真抄下來(lái)，甚至抄幾遍，邊抄遍理解，要想真正學(xué)好，一定要根據(jù)我的方法來(lái)做。
#include <reg51.h>
#define LCD1602_DB P0
sbit LCD1602_RS = P2^0;
sbit LCD1602_RW = P2^1;
sbit LCD1602_E = P2^2;
bit flagT0 = 0; //T0中斷產(chǎn)生標(biāo)志
unsigned char T0RH = 0; //T0重載值的高字節(jié)
unsigned char T0RL = 0; //T0重載值的低字節(jié)
unsigned char code str1[] = "Kingst Studio"; //待顯示的第一行字符串
unsigned char code str2[] = "Let's move..."; //待顯示的第二行字符串，需保持與第一行字符串等長(zhǎng)，較短的行可用空格補(bǔ)齊
void ConfigTimer0(unsigned int ms);
void LcdShowStr(unsigned char x, unsigned char y, const unsigned char *str, unsigned char len);
void LcdInit();
void main ()
{
unsigned char i;
unsigned char iMove = 0; //移動(dòng)索引
unsigned int tmrMove = 0; //屏幕移動(dòng)定時(shí)器
unsigned char pdata bufMove1[16 + sizeof(str1) + 16]; //移動(dòng)顯示的緩沖區(qū)
unsigned char pdata bufMove2[16 + sizeof(str1) + 16]; //移動(dòng)顯示的緩沖區(qū)
EA = 1; //開(kāi)總中斷
ConfigTimer0(10); //配置T0定時(shí)10ms
LcdInit(); //初始化液晶
for (i=0; i<16; i++) //緩沖區(qū)開(kāi)頭一段填充為空格
{
bufMove1[ i] = ' ';
bufMove2[ i] = ' ';
}
for (i=0; i<(sizeof(str1)-1); i++) //待顯示字符串拷貝到緩沖區(qū)中間位置
{
bufMove1[16+i] = str1[ i];
bufMove2[16+i] = str2[ i];
}
for (i=(16+sizeof(str1)-1); i<sizeof(bufMove1); i++) //緩沖區(qū)結(jié)尾一段也填充為空格
{
bufMove1[ i] = ' ';
bufMove2[ i] = ' ';
}
while(1)
{
if (flagT0)
{
flagT0 = 0;
tmrMove += 10;
if (tmrMove >= 500) //每500ms移動(dòng)一次屏幕
{
tmrMove = 0;
LcdShowStr(0, 0, bufMove1+iMove, 16); //從緩沖區(qū)抽出需顯示的一段字符顯示到液晶上
LcdShowStr(0, 1, bufMove2+iMove, 16);
iMove++; //移動(dòng)索引遞增，實(shí)現(xiàn)左移
if (iMove >= (16+sizeof(str1)-1)) //起始位置達(dá)到字符串尾部后即返回從頭開(kāi)始
{
iMove = 0;
}
}
}
}
}
void ConfigTimer0(unsigned int ms) //T0配置函數(shù)
{
unsigned long tmp;
tmp = 11059200 / 12; //定時(shí)器計(jì)數(shù)頻率
tmp = (tmp * ms) / 1000; //計(jì)算所需的計(jì)數(shù)值
tmp = 65536 - tmp; //計(jì)算定時(shí)器重載值
tmp = tmp + 12; //修正中斷響應(yīng)延時(shí)造成的誤差
T0RH = (unsigned char)(tmp >> 8); //定時(shí)器重載值拆分為高低字節(jié)
T0RL = (unsigned char)tmp;
TMOD &= 0xF0; //清零T0的控制位
TMOD |= 0x01; //配置T0為模式1
TH0 = T0RH; //加載T0重載值
TL0 = T0RL;
ET0 = 1; //使能T0中斷
TR0 = 1; //啟動(dòng)T0
}
void LcdWaitReady() //等待液晶準(zhǔn)備好
{
unsigned char sta;
LCD1602_DB = 0xFF;
LCD1602_RS = 0;
LCD1602_RW = 1;
do
{
LCD1602_E = 1;
sta = LCD1602_DB; //讀取狀態(tài)字
LCD1602_E = 0;
} while (sta & 0x80); //bit7等于1表示液晶正忙，重復(fù)檢測(cè)直到其等于0為止
}
void LcdWriteCmd(unsigned char cmd) //寫(xiě)入命令函數(shù)
{
LcdWaitReady();
LCD1602_RS = 0;
LCD1602_RW = 0;
LCD1602_E = 1;
LCD1602_DB = cmd;
LCD1602_E = 0;
}
void LcdWriteDat(unsigned char dat) //寫(xiě)入數(shù)據(jù)函數(shù)
{
LcdWaitReady();
LCD1602_RS = 1;
LCD1602_RW = 0;
LCD1602_E = 1;
LCD1602_DB = dat;
LCD1602_E = 0;
}
void LcdInit() //液晶初始化函數(shù)
{
LcdWriteCmd(0x38); //16*2顯示，5*7點(diǎn)陣，8位數(shù)據(jù)接口
LcdWriteCmd(0x0C); //顯示器開(kāi)，光標(biāo)關(guān)閉
LcdWriteCmd(0x06); //文字不動(dòng)，地址自動(dòng)+1
LcdWriteCmd(0x01); //清屏
}
void LcdShowStr(unsigned char x, unsigned char y, const unsigned char *str, unsigned char len) // 顯示字符串，屏幕起始坐標(biāo)(x,y)，字符串指針str，需顯示長(zhǎng)度len
{
unsigned char addr;
//由輸入的顯示坐標(biāo)計(jì)算顯示RAM的地址
if (y == 0)
{
addr = 0x00 + x; //第一行字符地址從0x00起始
}
else
{
addr = 0x40 + x; //第二行字符地址從0x40起始
}
//由起始顯示RAM地址連續(xù)寫(xiě)入字符串
LcdWriteCmd(addr | 0x80); //寫(xiě)入起始地址
while (len--) //連續(xù)寫(xiě)入字符串?dāng)?shù)據(jù)
{
LcdWriteDat(*str);
str++;
}
}
void InterruptTimer0() interrupt 1 //T0中斷服務(wù)函數(shù)
{
TH0 = T0RH; //定時(shí)器重新加載重載值
TL0 = T0RL;
flagT0 = 1;
}
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