At 11:41 AM 10/29/2009, Gordon Williams wrote: >There have been a number of threads now on eeprom loss of data problems and >this has got me concerned about PIC reliability. Is this common in all >eeproms in all PICs or are microchip's devices just crappy? > >Over the life of my divice I will read the eeprom less than 700 times. Is >this something that will cause problems? Can someone point me to a document >were the problem is described and specs given? This problem appeared to surface with Microchip's later chips (nanowatt series?). Early chips such as the venerable F84 or the early 16F628 don't have the problem, the (a) versions of the 16F628 (16F628A) apparently do have the problem. So, apparently, does the 12F675. So far as I know, reading the eeprom does NOT cause the problems, Instead, the problem is caused by many writes to one part of the eeprom array. Those bytes that are frequently written are NOT the problem. What does get affected is eeprom addresses that DON'T get written. I know that I've seen Microchip describe this in at least one data sheet but I'll be darned if I can find just WHICH data sheet that was (I spent 5 minutes looking just now). I'll post the URL for the appropriate data sheet when I run across it again. dwayne -- Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist