Installing and running
The simplest probably is to launch this program as WEB application. Then only one file USB-I2C.application will be download to your computer.
In the case you decide to install this program into disk of your computer, you have to start setup.exe. It unpacks self into 2 files: USB-I2C.exe and Microchip MCP2221DLL-M-dotNet4.dll , that are necessary for run on 32 or 64bit Windows. For older OS than Windows 7, i.e. Vista or XP SP3 maybe you also need to install USB driver http://www.microchip.com/wwwproducts/Devices.aspx?product=MCP2221#documentatin or/and .NET library. This free program is built direct in C# of "Visual Studio 13 community", which is designed for education. Software is signed but not certified CA and so warnings appear during install, although no malware hides inside program.
Then run USB_I2C.exe file:
You need to connect the computer and the MCP2221 USB/I2C bridge by USB cable with mini-B connector. Next you connect bridge and slave ICs by I2C bus: SCL,SDA,GND, 3.3 or 5V power (if missing). Bridge works as a master, and if other master IC is connected yet, probably you need to disconnect it. You can choose "Device" from upper menu strip . Besides of general I2C device for the present you may choose among 5 of types from hundreds of interesting devices:
24CXX Serial EEPROM
ADXL345 3-axes accelerometer(see picture)
DRV10983 BLDC motor driver (DRV10983 is described in particular manual).
DS1307 Real time clock and calendar
MCP4725 12-bit D/A converter
TC74 Temperature sensor
On menu File you can download or upload .hex , .csv or .bin file on disk to registers or memory of device.