A challenge in many Arduino projects is that it can be difficult to get I2C components working properly. Many times the libraries and demonstration code indicate a certain I2C address for the component, but the Arduino is unable to find the component at that Address. This can be a challenge, because often times we might not have the exact same version of the component that is assumed in the libraries and code. A perfect example of this are the SSD1306 OLED displays. Many of the components look identical, but they can have different I2C addresses. In order to overcome this challenge, the following code allows you to scan your I2C Bus, and list the address of all the components found. Simply attach the component as instructed in the component documentation. Then run the following code. It will list the address of the I2C components it finds. Then you can edit the sample code to use the proper address. Enjoy!
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#include <Wire.h> #define myWire Wire int numDevices; byte error, address; void setup() { myWire.begin(); Serial.begin(9600); Serial.println("Find I2C Devices: "); } void loop() { Serial.println("Scanning..."); numDevices = 0; for (address = 1; address < 127; address=address+1) { myWire.beginTransmission(address); error = myWire.endTransmission(); if (error == 0) { Serial.print("I2C device found at address 0x"); if (address < 16) Serial.print("0"); Serial.print(address, HEX); Serial.println(" !"); numDevices = numDevices + 1; } else if (error == 4) { Serial.print("Unknown error at address 0x"); if (address < 16) Serial.print("0"); Serial.println(address, HEX); } } if (numDevices == 0) Serial.println("No I2C devices found"); delay(5000); } |