Hello everyone.
I start this new topic because I have some problems for a project I have been assigned on.
First, you have to know that I am pretty new to everything concerning electricity, electronic, chips, sensors, etc... I have only done so programmation on C++ before, that's all.
My assignement is to connect, as the title says, a NodeMCU v1.0 ESP-12E to a LDC1614 (http://www.ti.com/product/LDC1614/datasheet) using the I2C protocol.
I have been looking a lot for different tutorials and other documentation on the net but I am still not able to perform what I would like to do.
What I did so far :
On a breadboard, the NodeMCU is connected to my computer via an USB-cable.
On the right side of the image, the 3v3 pin is connected to the + of the breadboard and the GND to the - .
The D5 is connected to the SCL pin of the LDC 1614 and the D6 to the SDA's one.
On the LDC1614 :
Apart from the SDA and SCL, the ADDR is connected to ground ( page 3 of the datasheet ) so the address of the LDC1614 will be 0x2A, SD is connected to ground and the INTB is connected to the + of breadbord.
How it looks like now :
To detect if an I2C device is connected to my NodeMCU, I use the following I2C scanner on ArduinoIDE :
http://playground.arduino.cc/Main/I2cScanner
but no device has been found so far.
Thank you for reading my long explanation, I would be very grateful if I could get some help on that 
If anything is missing in my explanation, please just ask me and I'll give the information.