> We converted an old static logic module to a PIC16C57 last year and sent to a > test house for EMC compliance testing this consisted of 8Kv air discharge to > the case of the equipment and exposure to RF field to 30V per meter. Well, if we're getting into old war stories. I worked on an industrial control system that had noise immunity as #1 on the design goals as the previous model was starting to get a reputation. When it was finished (it flew through the compliance testing) we could run a 6" spark down the casing or discharge directly onto the RS232 pins. The test I was most proud of, was applying 240V to the comms pins, blowing up the interface itself, but the CPU still didn't miss a tick. This was a pretty dense 4"x6" PCB with SMD on both sides and the serial interface on the same PCB (about 2" from the CPU). It had memory mirroring which would halt the system if it detected a fault as would the latching watchdog. And not a single opto in sight. I designed it, and I still don't believe it. ====================================================== Very funny Scotty. Now beam down my clothes. ====================================================== Steve Baldwin Electronic Product Design TLA Microsystems Ltd Microcontroller Specialists PO Box 15-680 email: steveb@kcbbs.gen.nz New Lynn, Auckland ph +64 9 820-2221 New Zealand fax +64 9 820-1929 ======================================================