Wire. Wire.begin(1) // join i2c bus with address #1 Here is the complete send side - #include The wiring of the two UNO's are directly from the example. Code samples in the reference are released into the public domain.It good to see so many responses from people that have used the wire library and know it inside and out. The text of the Arduino reference is licensed under aĬreative Commons Attribution-ShareAlike 3.0 License.

SPI library supports the entire Arduino SPI API including transactions. Wire.begin(0, 2) on ESP-01, else they default to pins 4(SDA) and 5(SCL). Before using I2C, pins for SDA and SCL need to be set by calling Wire.begin(int sda, int scl), i.e.

shift the value one bit to the right), yielding an address between 0 and 127.Ĭorrections, suggestions, and new documentation should be posted to the Forum. I2C (Wire library) Wire library currently supports master mode up to approximately 450KHz. Set the Wire Library mode to 2x Wire, Master or Slave. If you have a datasheet or sample code that uses 8 bit address, you'll want to drop the low bit (i.e. To me, that reads as saying the Wire library is not compatible with Due but I'm pretty sure that's wrong because Arduino SAM Boards does contain a Wire library, the example sketches are functionally identical to those in the examples page, and the Wire library reference page does mention the Due. Some settings must be set in the Arduino IDE for the library to function. The Wire library uses 7 bit addresses throughout. 7 bits identify the device, and the eighth bit determines if it's being written to or read from. There are both 7- and 8-bit versions of I2C addresses. Because of this, send() and receive() have been replaced with read() and write(). On the Arduino Mega, SDA is digital pin 20 and SCL is 21.Īs of Arduino 1.0, the library inherits from the Stream functions, making it consistent with other read/write libraries. On most Arduino boards, SDA (data line) is on analog input pin 4, and SCL (clock line) is on analog input pin 5. This library allows you to communicate with I2C / TWI devices. Reference Language | Libraries | Comparison | Changes