.用单片机的定时器和计数器设计一个秒表，LED采用BCD码显示，发光二极管亮表示0，暗表示1，从零开始计时，记到99后从头开始，依次循环，时间间隔为900ms，要求采用定时器0工作于工作方式2。-With the design of single-chip timers and counters a stopwatch, LED BCD code display, light emitting diode light 0, dark one, the timing of starting fro

vhdl learning materials，-VHDL based on the digital clock has an alarm clock, stopwatch, clock, date, stopwatch functions can start, pause, cleared, the clock can be set-up times, you can set the date