在使用12MHz晶振的条件下，由8051内部定时器1按方式1工作，即作为16位定时器使用，每0.05秒钟T1溢出中断一次。P1口的P1.0～P1.7分别接发光二极管的L1～L8。（用连线连接J2、J3）。

要求：编写程序模拟一循环彩灯。彩灯变化花样为：①L1、L2、…L8依次点亮；②L1、L2、…L8依次熄灭；③L1、L2、…L8全亮、全灭。各时序间隔为0.5秒。让发光二极管按以上规律循环显示下去。

编写一个救护车警笛声程序，要求：高低两种音调交替出现，交替周期1～1.5S。-Conditions of use 12MHz crystal, by 8051 internal timer according to the way a work, that is used as a 16-bit timer overflow interrupt every 0.05 seconds T1. P1 port P1.0 ~ P1.7, respectively, then the light-emitting diode L1 to L8. (Connect J2, J3). Requirements: write a program to simulate a cycle Lantern. Lantern changes in the pattern: a ' L1, L2, ... L8 were lit　② L1, L2, ... L8 off in order　③ L1, L2, ... L8 full brightness, Quanmie. The timing interval is 0.5 seconds. The light-emitting diode cycle continues above rules. Preparation of an ambulance siren program requirements: high and low tones alternating, alternating cycles 1.5S.