![]() ![]() ![]() scanI2C(5000000) // uncomment if the microcontroller supports this speed scanI2C(3400000) // uncomment if the microcontroller supports this speed scanI2C(1000000) // uncomment if the microcontroller supports this speed Thus, the sketch works slavishly through the address space for each transmission rate. Wire.endTransmission() returns “0” if it has worked. Wire.beginTransmission(adresse) starts communication with the I2C device. The Wire library is described on the Arduino web pages here. More information about I2C can be found here on Wikipedia. ![]() The Arduino Uno can only use the Fast Mode. Which clock can be set depends on both the I2C device and the microcontroller used. Since one bit is transmitted at each bar, the clock rate corresponds to the data rate in bits/s. Ultra Fast Mode: 5 MHz (unidirectional only).SDA transmits the data, SCL sets the clock and thus determines the data rate. The I2C bus consists of two lines, most commonly referred to as SDA and SCL. In addition, you may want to check which transfer speed your I2C component is suitable for. O maybe a circuit just doesn’t work and you want to check if the I2C part you’re using is responding at all. Sometimes this is not the case and then you need an I2C scanner. Ideally, you will find a data sheet describing the addressing. For modules, you can sometimes choose the address via jumpers. Therefore, most I2C components have two or three input pins, which you can set to LOW or HIGH to set multiple addresses. ![]() Since this is not very much, issues with duplicate addresses are not unlikely without further action. Strictly speaking, even on 8 to 127, as addresses 0 to 7 are reserved. The address space is limited to addresses from 1 to 127. In order to address several components via a single I2C bus, each of the components must have its own I2C address. This post is about an I2C scanner sketch that you can use to find out I2C addresses. In some posts I had dealt with components that are addressed by means of I2C (more precisely: I 2C), as for example in my last article about the MCP23017. ![]()
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