The XA-S3 is a member of Philips Semiconductors’ XA (eXtended Architecture) family of high performance 16-bit single-chip Microcontrollers. The XA-S3 combines many powerful peripherals on one chip. Therefore, it is suited for general multipurpose high performance embedded control functions.One of the on-chip peripherals is the I2C bus interface. This report describes worked-out driver software (written in C) to program / use the I2C interface of the XA-S3. The driver software, together with a demo program and interface software routines offer the user a quick start in writing a complete I2C - XAS3 system application.1. INTRODUCTION..........72. EXTERNAL (APPLICATION) INTERFACE 92.1 External data interface..92.2 External function interfaces .103. DRIVER OPERATION114. DEMO PROGRAM .....12APPENDIX 1 I2CINTFC.C ....13APPENDIX 2 I2CDRIVR.C....17APPENDIX 3 I2CEXPRT.H...20APPENDIX 4 DEMO.C.22