单项选择题 颅内血肿清除 的一次性的用物准备有哪些（）

单项选择题 MCU parallel I/O port line P1.0 to P1.3 connected to four LED, at this time it is what interface function?

未知题型 One button S1 controls 8 LEDs to display different patterns. When S1 is not pressed, 8 LEDs are fully turned on; when S1 is pressed, 8 LEDs cross on and off.