PSoC Designer provides a user module I2CHW, for implementing the I2C protocol in hardware. This hardware resource can work both as I2C Master and Slave.
Attached project demonstrates the usage of I2CHW user module configured as master to communicate with an external I2C EEPROM (24C256) which is an I2C slave. In this example, data is written to the external EEPROM and same data is read back to check if data was written to the external EEPROM without any errors.
The attached document provides complete information on the User modules, their placement, user module parameter settings, global resources settings, hardware connection, and detailed description on the working of the project.