监视开关K1（接在P3.0端口上），用发光二极管L1（接在单片机P1.0端口上）显示开关状态，如果开关合上，L1亮，开关打开，L1熄灭。 -Monitor switch K1 (then in the port P3.0), using light-emitting diodes L1 (in the single-chip access port P1.0) Show switch status, if the switch closed, L1 light, switch open, L1 extinguished.