[嵌入式]单片机项目式实训分支（显示）

学习内容：

1. 10s倒计时

2. 动态显示

3. LCD1602

10s倒计时

数码管引脚排列http://29cx.com/shuma/6010.html74LS47译码器：tips:译码器应与数码管寻求匹配，如共阳就配低电平有效的译码器。

74LS47译码器https://wenku.baidu.com/view/d1a54ca4c47da26925c52cc58bd63186bceb922c.html位选和段选：位选选数码管，段选输出数码段。tips:先段选后位选，会重影。

位选和段选https://wenku.baidu.com/view/8725fc2e753231126edb6f1aff00bed5b8f37343.html

#include<reg52.h>
#define uint unsigned int 
void main()
{
    char ctime;
    for(ctime = 9;ctime > 0;ctime--)
    {
        P0 = ctime;
        delay();
    }
    while(1);
}

void delay()
{
uint i,j;
for(i = 1000;i > 0;i--)
for(j = 115;j > 0;j--);
}
//tips:自动转换进制

then

#include<reg52.h>
#define uchar unsigned char
uchar code led[] = {0x81,0xf3,0x49,0x61,0x33,0x25,0x05,0xf1,0x01,0x21};//段选
ucahr code ledw[] = {0xf7,0xfb,0xfd,0xfe};//位选
uchar utime[4];

void delay(uchar xms);
void main()
{
    int ctime;
    uchar b,c;
    for(ctime = 999;ctime > 0;ctime--)
    {
        utime[0] = ctime%10;
        utime[1] = ctime/10%10;
        utime[2] = ctime/100%10;
        for(c = 0;c < 33;c++)
        {
            for(b = 0;b <= 2;b++)//类似动态扫描
            {
                P0 = led[utime[b]];
                P1 = ledw[b];
                delay(10);
            }
        }
    }while(1);
}

void delay(uchar xms)
{
    uchar i,j;
    for(i = 0;i < xms;i++)
    for(j = 0;j < 115;j++);
}

动态显示（利用发光管余晖和人眼视觉暂留作用）

tips:明确共阳还是共阴，段选要一一对应，不然乱码。动态显示依靠快速位选端。

#include<reg52.h>
#define uchar unsigned char
uchar code led[] = {0xf3,0x49,0x61,0x33};
uchar code ledw[] = {0xfe,0xfd,0xfb,0xf7};
void delay(uchar xms);

void main()
{
    while(1)
    {
        uchar b;
        for(b = 0;b < 4;b++)
        {
            P0 = led[b];
            P1 = ledw[b];
            delay(xms);
        }
    }
}
void delay(uchar xms)//略去不写

LCD1602

lcd1602https://blog.csdn.net/aaaaaaaa123345/article/details/124212417

#include<reg52.h>
#include<stdio.h>
#define uchar unsigned char
#define uint unsigned int 

sbit lcden = P2^0;//enable
sbit lcdrs = P2^1;//choose data
void delay(uint xms);

void write_com(uchar com)//write com
{
    lcdrs = 0;
    P0 = com;
    delay(5);
    lcden = 1;
    delay(5);
    lcden = 0;
}

void write_data(uchar data)//write data
{
    lcdrs = 1;
    P0 = data;
    delay(5);
    lcden = 1;
    delay(5);
    lcden = 0;
}

void LCDloc(char x,char y)//set position 
{
    if(x == 1)
    {
        write_come(0x80+y);
    }
    else
    {
        write_come(0xc0+y);
    }
}

char putchar(char c)
{
    write_data(c);
    return(c);
}

void init()//start
{
    lcden = 0;
    write_com(0x38);
    write_com(0x0c);
    write_com(0x06);
    write_com(0x01);
    write_com(0x80);
}

void main()
{
    int ctime;
    init();
    for(ctime = 999;ctime > 0;ctime--)
    {
        LCDloc(1,2);
        printf("%d",ctime);
        delay(1000);
    }
    while(1);
}

void delay(uint xms)
{
    uint i,j;
    for(i = 0;i < xms;i++)
        for(j = 0; j < 115;j++);
}