用于令与PORTD口相连的8个发光二极管前4个点亮，后4个熄灭。在调试程序前，应使与PORTD口相连的8位拔码开关拔向相应的位置。-I used to make and PORTD LEDs connected to the eight first 4 lights out after 4. In the debugging process, should make PORTD I connected with the 8-bit code switch pulled to pull the corresponding position.