引脚说明
GND ------ 地线
VCC ------ 电源（5V or 3.3v 电源不同显示效果有点差别）
SDA ------ I2C 数据线
SCL ------ I2C 时钟线
接线方法
LCD1602 i2c模块 Ardunio Uno
GND <------> GND接地线
VCC <------> 5V 接电源
SDA <------> A4
SCL <------> A5
按键模块
K6 （set端口） <------> 7
K7 （加） <------> 6
K8 （减） <------> 5
需要用到LCD1602 I2C的库，下载地址是 https://github.com/marcoschwartz/LiquidCrystal_I2C
程序如下：
#include <Wire.h>
#include <LiquidCrystal_I2C.h> //引用I2C库
//设置LCD1602设备地址，这里的地址是0x3F，一般是0x20，或者0x27，具体看模块手册
LiquidCrystal_I2C lcd(0x3F,16,2);
#define choose 7 //选择端口
#define add 6 //加
#define minus 5 //减
unsigned long seconds;
int s = 0, m = 0, h = 0, d = 0, mon = 0, y = 0; //时间进位
int second = 0, minute = 0, hour = 0, day = 0, month = 0, year = 0; //当前时间
int SECOND = 0, MINUTE = 0, HOUR = 0, DAY = 0, MONTH = 0, YEAR = 0; //初始时间
int chose = 0, ButtonDelay = 10;
void setup(){
for(int i = 6;i <= 9; i++){
pinMode(i,OUTPUT);
}
digitalWrite(add, HIGH);
digitalWrite(minus, HIGH);
digitalWrite(choose, HIGH);
lcd.init(); //初始化LCD1602
lcd.backlight(); //设置LCD背景等亮
set(2018, 7, 25, 12, 30, 50);
}
/** 格式化输出 */
void FormatDisplay(int col, int row,int num){
lcd.setCursor(col, row);
if(num < 10){
lcd.print("0");
}
lcd.print(num);
}
/** 计算时间 */
void time(){
second = (SECOND + seconds) % 60; //计算秒
m = (SECOND + seconds) / 60; //分钟进位
FormatDisplay(6,1,second);
minute = (MINUTE + m) % 60; //计算分钟
h = (MINUTE + m) / 60; //小时进位
FormatDisplay(3,1,minute);
hour = (HOUR + h) % 24; //计算小时
d = (HOUR + h) / 24; //天数进位
FormatDisplay(0,1,hour);
lcd.setCursor(2, 1); lcd.print(":");
lcd.setCursor(5, 1); lcd.print(":");
}
/** 根据年月计算当月天数 */
int Days(int year, int month){
int days = 0;
if(month != 2){
switch(month){
case 1: case 3: case 5: case 7: case 8: case 10: case 12: days = 31; break;
case 4: case 6: case 9: case 11: days = 30; break;
}
}
else{ //闰年
if(year % 4 == 0 && year % 100 != 0 || year % 400 == 0){
days = 29;
}
else{
days = 28;
}
}
return days;
}
/** 计算当月天数 */
void Day(){
int days = Days(year,month);
int days_up;
if(month == 1){
days_up = Days( year - 1, 12 );
} else{
days_up = Days( year, month - 1 );
}
day = (DAY + d) % days;
if(day == 0){
day = days;
}
if((DAY + d) == days + 1){
DAY -= days;
mon++;
}
if((DAY + d) == 0){
DAY += days_up;
mon--;
}
FormatDisplay(8,0,day);
}
/** 计算月份 */
void Month(){
month = ( MONTH + mon ) % 12;
if(month == 0){
month = 12;
}
y = (MONTH + mon - 1) / 12;
FormatDisplay(5,0,month);
lcd.setCursor(7, 0);
lcd.print('-');
}
/** 计算年份 */
void Year(){
year = (YEAR + y) % 9999;
if(year == 0){
year = 9999;
}
lcd.setCursor(0, 0);
if(year < 1000){
lcd.print("0");
}
if(year < 100){
lcd.print("0");
}
if(year < 10) {
lcd.print("0");
}
lcd.print(year);
lcd.setCursor(4, 0);
lcd.print('-');
}
/** 根据年月日计算星期几 */
void Week(int y,int m, int d){
if(m == 1) m = 13;
if(m == 2) m = 14;
int week = (d+2*m+3*(m+1)/5+y+y/4-y/100+y/400)%7+1;
String weekstr = "";
switch(week){
case 1: weekstr = "Mon. "; break;
case 2: weekstr = "Tues. "; break;
case 3: weekstr = "Wed. "; break;
case 4: weekstr = "Thur. "; break;
case 5: weekstr = "Fri. "; break;
case 6: weekstr = "Sat. "; break;
case 7: weekstr = "Sun. "; break;
}
lcd.setCursor(11, 0); lcd.print(weekstr);
}
/** 显示时间、日期、星期 */
void Display(){
time();
Day();
Month();
Year();
Week(year,month,day);
}
/** 显示光标 */
void DisplayCursor(int rol, int row){
lcd.setCursor(rol, row);
lcd.cursor();
delay(100);
lcd.noCursor();
delay(100);
}
/** 设置初始时间 */
void set(int y, int mon, int d, int h, int m, int s){
YEAR = y;
MONTH = mon;
DAY = d;
HOUR = h;
MINUTE = m;
SECOND = s;
}
/** 通过按键设置时间 */
void Set_Time(int rol, int row, int &Time){
DisplayCursor(rol, row);
if(digitalRead(add) == LOW){
delay(ButtonDelay);
if(digitalRead(add) == LOW){
Time ++;
}
Display();
}
if(digitalRead(minus) == LOW){
delay(ButtonDelay);
if(digitalRead(minus) == LOW){
Time --;
}
Display();
}
}
/** 按键选择 */
void Set_Clock(){
if(digitalRead(choose)==LOW){
lcd.setCursor(9, 1); lcd.print("SetTime");
while(1){
if(digitalRead(choose)==LOW){
delay(ButtonDelay);
if(digitalRead(choose)==LOW){
chose++;
}
}
seconds = millis()/1000;
Display();
if(chose == 1){
Set_Time(1, 1, HOUR); //SetHour
}else if(chose == 2){
Set_Time(4, 1, MINUTE); //SetMinute
}else if(chose == 3){
Set_Time(7, 1, SECOND); //SetSecond
}else if(chose == 4){
Set_Time(9, 0, DAY); //SetDay
}else if(chose == 5){
Set_Time(6, 0, MONTH); // SetMonth
}else if(chose == 6){
Set_Time(3, 0, YEAR); //SetYear
}else if(chose >= 7){
chose = 0;
lcd.clear();
break;
}
}
}
}
void loop(){
seconds = millis()/1000; //获取单片机当前运行时间
Display(); //显示时间
Set_Clock(); //设置时间
}