0x00 for example would be saved as '00000000', '01010101', and '11111111'. I can't say that Serial EE's are less prone to failure, but for the amount of data I was writing, I felt it would impart less writes to each cell, thereby not getting as close to the limits. Plus the extra space allowed me to do the RAID-type system much easier. Due to other timing constraints, I am not reading back to verify each byte group, but I'm writing to multiple groups, and with the data growing continuously, a scan of all groups on power up easily tells me which one was the latest. A microchip FAE/tech told me that what fails is the charge pump, but the info on this list indicates that the cells fail. I look at the bottom line -- I've seen 5 failures (on 4 different instances of this circuit/product) with the system that stored data on the PIC's EEPROM, and no failures so far with the Serial-EE version (touch tree-trunks full of wood). Cheers, -Neil. > -------- Original Message -------- > Subject: Re: [PIC] "Best of" PIC EEPROM Algorithm Clarified > From: Peter Todd > Date: Wed, April 26, 2006 7:09 pm > To: "Microcontroller discussion list - Public." > > On Wed, Apr 26, 2006 at 01:47:39PM -0700, Picdude wrote: > > Having been bitten by EEPROM failure on the PICs in the the past, I ended up using a serial EE and doing most of this, after discussion on and advice from this list. I also flipped bits in the copies of each byte so in case the EE all fails to a certain state, it won't be identified as valid data. > > Flipped bits? Clever, and smart, I wouldn't have thought of that one. > > Do you think the stand-alone serial EEPROMs are less prone to failure? I > mean, the few ones I've seen datasheets for, say the same reliability > figures as PICs, but all the same... > > Be really nice if some MFG made an EEPROM with wear-leveling tech built > into it for a cheap price... Of course, that's what flash memory is > really. > > -- > pete@petertodd.ca http://www.petertodd.ca > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist