Verilog投币式手机充电仪

清华大学数字电子技术基础课程EDA大作业。刚上电数码管全灭，按开始键后，数码管显示全为0。输入一定数额，数码管显示该数额的两倍对应的时间，按确认后开始倒计时。输入数额最多为20。若10秒没有按键，数码管全灭。(Verilog coin operated cell phone charger

EDA major homework of digital electronic technology foundation course, Tsinghua University. Just put on the digital tube completely extinguished, press the start button, the digital tube display is 0. Enter a certain amount, the digital tube shows the amount of double the corresponding time, according to the confirmation began countdown. The maximum amount of input is 20. If there is no button in 10 seconds, the digital tube will die out.)