用1602做个液晶时钟，第一行显示年-月-日，第二行显示时-分-秒；
通过矩阵键盘上的按键K1按下，此时时钟停止，
K1按一下，光标移动到秒位，两下移到秒十位……光标随着移动到时-分-秒，年-月-日上，
按下K2，K3增加，减小更改光标所在位置上的数值；
按下K4启动时钟(Make a liquid crystal clock with 1602, the first line shows the year - month - day, the second line display - - minutes - seconds;
Press the button on the matrix keyboard, K1, when the clock stops,
K1 press, move the cursor to seconds, and move two to ten seconds...... The cursor moves with time, minutes, seconds, years, months, days,
Press K2, K3 to increase, and reduce the number of changes to the cursor's location;
Press K4 to start the clock.)