Reading = Wire. Wire.requestFrom(address, numBtyes) // request 2 bytes from slave device #112 new values to the register the I2C loop mode is in error write(busAddress.
Wire.endTransmission(false) // repeated start includeWire.write(byte(reg)) // sets register pointer Uint8_t reg = 0x04 // BatterySystemInfo() register Uint8_t address = 0x0A // 0x14, but Wire i2c adressing uses the high 7 bits so shift right Let me know if you still have any trouble.
The endTransmission() function, with no argument, does a stop and then a start which will not work here.īelow is some working sample code that will repeatedly read this register. The problem may be that the LTC1760 needs an actual repeated start bit. My read code is as follows, and initiates after the ackcheck in my wire.endTransmission above replies with a 0.Īnyone have any thoughts? I'm just plain stuck. I didn't include the code in my question in an attempt for brevity, which in retrospect was probably confusing. Int x = Wire.Thanks for the help! I am already using the Wire.read() command, unfortunately. While(Wire.available()) // slave may send less than requestedĬhar c = Wire.read() // receive a byte as character Wire.requestFrom(2, 6) // request 6 bytes from slave device #2
Serial.begin(9600) // start Serial for output Nick Gammon came up with a fantastic C++ template to allow sending data, regardless of data types. Wire library - Master Reader/Slave Sender The Wire library has no concept of data types, and only permits sending data as bytes. Int x = Wire.read() // receive byte as an integer
While(1 < Wire.available()) // loop through all but the lastĬhar c = Wire.read() // receive byte as a character this function is registered as an event, see setup() function that executes whenever data is received from master It does not change the value of the data or add any new data. On the OSR USB FX2 device, these two endpoints are configured for loopback, so the device moves data from the bulk-in endpoint to the bulk-out endpoint. Serial.begin(9600) // start serial for output Next, send data to the devices bulk-in and bulk-out endpoints that can be used for read and write requests, respectively. Wire.onReceive(receiveEvent) // register event Wire.begin(4) // join i2c bus with address #4 Wire.endTransmission() // stop transmitting Wire.beginTransmission(4) // transmit to device #4 Wire.begin() // join i2c bus (address optional for master) In this way, it's possible for your Arduino or Genuino boards to communicate with many device or other boards using just two pins of your microcontroller, using each device's unique address.
The bits after contain the memory address on the Slave that the Master wants to read data from or write data to, and the data to be written, if any.Įach Slave device has to have its own unique address and both master and slave devices need to take turns communicating over a the same data line line. eight clock pulses) from the Master to Slaves contain the address of the device the Master wants data from. When this information is sent - bit after bit -, the called upon device executes the request and transmits it's data back - if required - to the board over the same line using the clock signal still generated by the Master on SCL as timing. The I2C protocol involves using two lines to send and receive data: a serial clock pin (SCL) that the Arduino or Genuino Master board pulses at a regular interval, and a serial data pin (SDA) over which data is sent between the two devices.Īs the clock line changes from low to high (known as the rising edge of the clock pulse), a single bit of information - that will form in sequence the address of a specific device and a a command or data - is transferred from the board to the I2C device over the SDA line.
Once that message is received, it can then be viewed in the Slave board's serial monitor window opened on the USB connected computer running the Arduino Software (IDE). In this example, two boards are programmed to communicate with one another in a Master Writer/Slave Receiver configuration via the I2C synchronous serial protocol.Īrduino 1, the Master, is programmed to send 6 bytes of data every half second to a uniquely addressed Slave. In some situations, it can be helpful to set up two (or more!) Arduino or Genuino boards to share information with each other.
Wire library - Master Writer/Slave Receiver