说明：  先检测NRF24L01模块是否存在，在检测到NRF24L01模块之后，根据KEY0和KEY1的设置来决定模块的工作模式，在设定好工作模式之后，就会不停的发送/接收数据，同样用DS0来指示程序正在运行。
(First detect whether the nRF24L01 module exists. After detecting the nRF24L01 module, determine the working mode of the module according to the settings of key0 and key1. After setting the working mode, it will send / receive data continuously, and also use DS0 to indicate that the program is running.)