MicroPython ESP32I2C功能使用介绍

Posted 2022-08-23 perseverance52

【MicroPython ESP32】I2C功能使用介绍

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• 本示例基于Thonny平台开发。
• 参考官方文档：http://docs.micropython.org/en/latest/esp32/quickref.html#software-i2c-bus

硬件I2C总线

有两个标识符为0和1的I2C硬件外设。任何可用的支持输出的引脚都可以用于SCL和SDA，但下面给出了默认值。

	I2C(0)	I2C(0)
SCL	18	25
SDA	19	26

• 默认的I2C引脚引用方法：

from machine import Pin, I2C
i2c = I2C(0) # 默认的i2c0：scl:18 sda:19
i2c = I2C(1) # 默认的i2c1：scl:25 sda:26

等价于：

from machine import Pin, I2C
i2c = I2C(scl=Pin(18), sda=Pin(19),freq=400000)
i2c = I2C(scl=Pin(25), sda=Pin(26),freq=400000)

• 也可以自定义切换指定引脚

from machine import I2C,
i2c = I2C(1, scl=Pin(5), sda=Pin(4), freq=400000)

软件I2C总线

软件 I2C（使用 bit-banging）适用于所有具有输出功能的引脚，并通过machine.SoftI2C类访问：

• 引用方式如下：

from machine import SoftI2C
i2c = SoftI2C(scl=Pin(22),sda=Pin(23),freq=100000)

测试示例这里给出I2C设备地址扫描程序

from utime import sleep # 延时函数在utime库中
from machine import Pin
#from machine import I2C,
from machine import SoftI2C
#i2c = I2C(scl=Pin(18), sda=Pin(19),freq=400000) # Hardware I2C引用
#i2c = I2C(1, scl=Pin(5), sda=Pin(4), freq=400000) # 自定义切换引脚
i2c = SoftI2C(scl=Pin(22),sda=Pin(23),freq=100000) # softi2c引用
led = Pin(2,Pin.OUT)
#i2c = I2C(1)


if __name__ == '__main__':
    while True:             # 无限循环
        print("helloworld")  # 打印"helloworld"字串到console中
        sleep(5)      # 打印完之后休眠1秒
        print('Scan i2c bus...')
        devices = i2c.scan()

        if len(devices) == 0:
            print("No i2c device !")
        else:
            print('i2c devices found:',len(devices))
            
            for device in devices:
                print("Decimal address: ",device," | Hexa address: ",hex(device))
                led.value(led.value()^1)