先看看基本用法：

from pyb import I2C

i2c = I2C(1)                         # create on bus 1

i2c = I2C(1, I2C.MASTER)             # create and init as a master

i2c.init(I2C.MASTER, baudrate=20000) # init as a master

i2c.init(I2C.SLAVE, addr=0x42)       # init as a slave with given address

i2c.deinit()                         # turn off the peripheral

i2c.init(I2C.MASTER)

i2c.send(‘123‘, 0x42)        # send 3 bytes to slave with address 0x42

i2c.send(b‘456‘, addr=0x42)  # keyword for address

i2c.is_ready(0x42)           # check if slave 0x42 is ready

i2c.scan()                   # scan for slaves on the bus, returning

#   a list of valid addresses

i2c.mem_read(3, 0x42, 2)     # read 3 bytes from memory of slave 0x42,

#   starting at address 2 in the slave

i2c.mem_write(‘abc‘, 0x42, 2, timeout=1000) # write ‘abc‘ (3 bytes) to memory of slave 0x42

# starting at address 2 in the slave, timeout after 1 second

I2C的用法：

class pyb.I2C(bus, ...)

bus，I2C总线的序号

i2c.deinit()，解除I2C定义

i2c.init(mode, *, addr=0x12, baudrate=400000, gencall=False)，初始化

mode，只能是 I2C.MASTER 或 I2C.SLAVE

addr，7位I2C地址

baudrate，时钟频率

gencall，通用调用模式

i2c.is_ready(addr)，检测I2C设备是否响应，只对主模式有效

i2c.mem_read(data, addr, memaddr, *, timeout=5000, addr_size=8)，读取数据

data，整数或者缓存

addr，设备地址

memaddr，内存地址

timeout，读取等待超时时间

addr_size，memaddr的大小。8位或16位

i2c.mem_write(data, addr, memaddr, *, timeout=5000, addr_size=8)，写入数据，参数含义同上

i2c.recv(recv, addr=0x00, *, timeout=5000)，从总线读取数据

recv，需要读取数据数量，或者缓冲区

addr，I2C地址

timeout，超时时间

i2c.send(send, addr=0x00, *, timeout=5000)

send，整数或者缓冲区

addr，I2C地址

timeout，超时时间

i2c.scan()，搜索I2C总线上设备。