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

交通灯实现,可以实现倒计时显示和灯的闪烁-tfaffic lights