On Dec 13, 2007 8:38 PM, Matthew Rhys-Roberts wrote: > Will someone correct me if I'm wrong about this? > > As far as I can tell, writing (i.e. erase-writing) to any PIC EEPROM > address will disrupt the stored charge in neighboring memory cells. > Eventually, if written enough times, EEPROM data corruption may result. > Microchip recommend using an EEPROM refresh routine periodically, in > cases where erase-write cycles are likely to approach 1- to 10-million > times ("specification D124"). Which PIC are you using? Have you checked the errata? > I'm only asking so I can make a sensible choice between EEPROM and Flash > program memory, for storing some infrequently changed non-volatile > constants. I can not relate this paragraph with the previous paragraph. Since it is infrequent, you can use either EEPROM or Flash but I think EEPROM is easier if your PIC has the EEPROM. Anyway, you need to tell us which PIC you are going to use first. Xiaofan -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist