Hi Mr? Minchang, > I FOUND THE I2C VHDL CORE INTRODUCTION, > > BUT I CAN'T FIND THE SOURCE CODE ANYWHERE, http://member.nifty.ne.jp/fpga/freeip/i2cif/index.html http://member.nifty.ne.jp/fpga/freeip/i2cif/i2creg.html Mr.Basaro in Japan provides free IP for I2C interface.