On Mon, 9 Mar 1998 23:34:01 -0400 John Hansen writes: >Hi: > > I am working on a program that is going to do a lot of writing >to the EEPROM data memory on a 16F84. Microchip estimates that >these chips are good for 1,000,000 write/erase cycles. Does >anyone know what this means? Does it mean that each byte >individually is rated for 1,000,000 cycles Yes, it means exactly that. Each EEPROM byte wears out independently from the others. If you write a small amount of data lots of times, try to spread it out rather than always writing to the same location. Also having multiple copies of the data may allow the program to compensate for failure of one location. The rated number of cycles is on the very leading tail of the "bell curve" (likely not bell-shaped in this case) of the number of cycles until failure. Most bytes will last much longer. A very few will fail earlier. I think the explanation from Microchip is that less than 1% of chips will have 1 or more bytes failed after all bytes have been cycled the rated number of times. _____________________________________________________________________ You don't need to buy Internet access to use free Internet e-mail. Get completely free e-mail from Juno at http://www.juno.com Or call Juno at (800) 654-JUNO [654-5866]