上一节带大家一起实现了LED的点灯效果，让大家熟悉IO控制输出的基础方法，可能大家对代码还有疑问，下面大家一起来看下。
一、machine模块支持以下函数
Pin, Timer, ADC, I2C和Soft I2C, SPI和Soft SPI, WDT, PWM, UART
上电初始化引脚函数格式：
machine.Pin(pin,mode,pull,value,alt)
重新初始化引脚函数格式：
Pin.init(pin,mode,value,driver,at)
?另外还有：
machine.reset() 复位设备，等同于按下外部复位按钮
machine.reset_cause() 返回复位原因
machine.disable_irq() 关闭中断请求
machine.enable_irq() 使能中断请求
machine.freq() 返回CPU运行速率参数
二、电路连接
LED通过一个限流电阻连接到GPIO, LED可通过拉电流或者推电流模式连接。拉电流模式引脚输出低点亮，推电流模式引脚输出高LED点亮。
我们在代码里LED分配了GP0并且配置这个引脚为输出。然后每隔一秒闪烁一次。
下面我们再来实现两个LED灯交替闪烁的例子：
?红色LED连接的GPIO口是流入电流的。白色LED连接的GPIO口是流出电流的。
main.py：
# 这个例子是实现外接2个LED交替闪烁
import machine
import utime
red_LED = machine.Pin(0,machine.Pin.OUT) #端口0
white_LED = machine.Pin(7,machine.Pin.OUT) #端口7
while True:
red_LED.value(1) # 红色LED 亮起
white_LED.value(1) # 白色LED 亮起
utime.sleep(1) # 延迟1秒
red_LED.value(0) # 红色LED 熄灭
white_LED.value(0) # 白色LED 熄灭
utime.sleep(1) # 延迟1秒diagram.json
{
"version": 1,
"author": "Anonymous maker",
"editor": "wokwi",
"parts": [
{
"type": "wokwi-pi-pico",
"id": "pico",
"top": 0,
"left": 0,
"attrs": { "env": "micropython-20220117-v1.18" }
},
{
"type": "wokwi-led",
"id": "led1",
"top": -2.89,
"left": 116.74,
"attrs": { "color": "white", "flip": "", "lightColor": "blue" }
},
{
"type": "wokwi-resistor",
"id": "r1",
"top": 96.97,
"left": 91.4,
"rotate": 180,
"attrs": { "value": "470" }
},
{
"type": "wokwi-led",
"id": "led2",
"top": -74.72,
"left": 2.51,
"attrs": { "color": "red" }
},
{
"type": "wokwi-resistor",
"id": "r2",
"top": -39.12,
"left": 63.93,
"attrs": { "value": "470" }
}
],
"connections": [
[ "led1:C", "r1:1", "green", [ "v35.22", "h26.2" ] ],
[ "r1:2", "pico:GND.6", "green", [ "v0" ] ],
[ "led1:A", "pico:GP7", "green", [ "v0" ] ],
[ "led2:A", "r2:1", "green", [ "v0" ] ],
[ "r2:2", "pico:3V3", "green", [ "v0" ] ],
[ "led2:C", "pico:GP0", "green", [ "v18.7", "h-36.48" ] ]
]
}好了，点灯就到此为止了。