本抢答器具有倒计时、定时、自动（或手动）复位、报警、屏幕显示、按键发光等多种功能的技术合-The Answer has the countdown, timer, automatic (or manual) reset, alarm, screen display, multi-function button LED technology, etc. All

Illustrate the use of PIC18 as a countdown Timer

A countdown timer written in PHP