.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

用单片机控制8个LED发光二极管实现如下显示方式：偶数灯先闪烁4次，奇数灯再闪烁4次，循环不止。其中闪烁延时1s，要求用查询方式下定时器1（工作方式2）来实现。-MCU control 8 LED light-emitting diodes to achieve the following display: an even number of light first flashes 4 times, the odd light flashes 4 times, the cycle is more