A simple count-down LED timer that counts in minutes and seconds. Three buttons below the LED provide control of the unit, allowing you set the desired countdown time in minutes and seconds and a start/stop button. Completion of the countdown is in

基于ARM9的倒计时秒表，用QT绘制界面，倒计时为零LED闪烁，有加减计时，暂停，启动，复位，单片机复位等功能-ARM9-based countdown stopwatch with QT drawing interface, the countdown to zero LED flashes, there is plus or minus timing, pause, start, reset, the microcontroller reset function