![]() ![]() One of the commonly used techniques is the I2C (or TWI) protocol. #Arduino wire library multiple bytes how toĪhh what we have here is a basic question on how to design I2C communication.It can be practical, especially in home automation projects, to communicate between several devices. Unfortunately Examples for I2C master and slave included in Arduino IDE are IMO too limited to provide clear guidance on this matter.įirst of all in your examples the master and slaves roles are exchanged and should be switched. Slave should read values from analog inputs and master should request them. Why? Because it's master which should decide when to request values and properly decode the request. Slave should provide proper answer to a given request eliminating the problem of data interpretation. ![]() I2C communication is based on requestFunction-(wait)-requestResponse sequence controlled by the master. Wire.requestFrom(112, 2) // request 2 bytes from slave device #112 Second: master requests response: // step 4: request reading from sensor 10 - 50 ms to process requests but in the example I'm refering to master doesn't delay read) Wire.endTransmission() // stop transmitting Wire.write(byte(0x02)) // sets register pointer to echo #1 register (0x02) Wire.beginTransmission(112) // transmit to device #112 In a nutshell:įirst: master requests a function to measure distance: // step 3: instruct sensor to return a particular echo reading Plese refer to the range finder example on arduino page. Third: master tries to read and analyze response. Here is how I do it you can follow my pattern and get extensible slave implementation which will support one function: read analog inputs but can be easily extended by adding additional function codes and required processing implementation to the slave main loop You should design reliable I2C communication in a similar way. Some kind of a simple protocol is needed to control slave - e.g. #Arduino wire library multiple bytes how to. ![]()
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