class OneWire – One-Wire Protocol

2024-01-02

This class provides One-Wire communication functionality. This feature is currently only supported on the EC200U/EC600U/EG912U/EG915U series.

Constructor

machine.OneWire

class machine.OneWire(GPIO)

Parameter:

  • GPIO - The gpio used, int type.

Example:

from machine import OneWire
obj=OneWire(OneWire.GPIO19)# Create a One-Wire object using GPIO19

Methods

OneWire.reset

OneWire.reset()

This method is used to reset the bus and detect if a device responds. It needs to be called before calling read/write methods.

Return Value:

Returns int value 0 indicating correct response, returns int value -1 indicating no response.

OneWire.read

OneWire.read(len)

This method is used to read data.

Parameter:

  • len - The length of data to read, int type.

Return Value:

Returns the read bytes object.

OneWire.write

OneWire.write(data)

This method is used to write data.

Parameter:

  • data - The data to write, bytes type.

Return Value:

Returns int value 0.

Example: Read DS18B20 data

Needs to work with DS18B20!

from machine import OneWire  

obj=OneWire(OneWire.GPIO19)  
data1=bytearray([0xcc,0x44])
data2=bytearray([0xcc,0xbe])

obj.reset()#First reset bus and detect if slave device responds, then read/write
obj.write(data1) 
obj.reset()
obj.write(data2)
obj.read(2)#The read data is the raw DS18B20 data, needs to be converted to actual temperature based on DS18B20 data format