Sir "Board" level buses, (IIC, etc) are not intended for external use. Note that the electrical part of these "standards" do not really address EMC issues. These busses are intended as internal constructions (no permanent external "port"), logic-level, and are mostly just software protocols.
I personnaly prefer RS422 or 488 if I need to stream data external to my "box". For data port surge suppression issues, look at application notes on the Maxim, TI, or LT websites for serial I/O ICs. good luck Brian -----Original Message----- From: Alex McNeil [ mailto:[email protected]] Sent: Thursday, January 16, 2003 12:58 AM To: [email protected] Subject: I2C bus sensitivity to EFT Hi Forum, Has anyone on this forum worked with I2C products and maybe be able to advise on the best method to suppress EFT noise that would alow the I2C bus, via external cables, to operate as expected e.g. Good EFT devices? How best to shield the I2C? Other? As always I look forward to your proffesional advice. History I have a system that connects 3 products (powered from an in-line external non-earthed power supply, SELV) using the I2C bus via a 1m shielded and 1m shielded curly cable. I use an I2C bi-directional extender IC P82B715 on one of the products. The I2C protocol gets corrupted when I appply the Electrical Fast Transient (EFT) Test per the EMC Standard EN61000-4-4. I have tried shielded cables, several EFT devices and 1nF caps on the lines but with little affect. Kind Regards Alex McNeil at:
