Hi, Anybody come across continous background checksum tests on eeprom?? Is it worth doing ??
Continous eeprom checksum microcontroller
Started by ●July 3, 2004
Reply by ●July 3, 20042004-07-03
"Vishal" <vishalpatil_89@yahoo.co.in> wrote in message news:8c90af46.0407022034.353ee2e0@posting.google.com...> Hi, Anybody come across continous background checksum tests on > eeprom?? Is it worth doing ??Yes, I do it all the time. Whether it's worth doing depends on whether you need to know if the memory has failed. Probably not for a musical greeting card, probably yes for a radiotherapy dosing controller. Cheers, Alf
Reply by ●July 3, 20042004-07-03
On 2 Jul 2004 21:34:16 -0700, the renowned vishalpatil_89@yahoo.co.in (Vishal) wrote:>Hi, Anybody come across continous background checksum tests on >eeprom?? Is it worth doing ??a) I've implemented it. b) I think so. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
Reply by ●July 3, 20042004-07-03
"Spehro Pefhany" <speffSNIP@interlogDOTyou.knowwhat> schreef in bericht news:5mcde01h0d05orbkpc6jga0gd8kq5lrced@4ax.com...> On 2 Jul 2004 21:34:16 -0700, the renowned vishalpatil_89@yahoo.co.in > (Vishal) wrote: > > >Hi, Anybody come across continous background checksum tests on > >eeprom?? Is it worth doing ?? > > a) I've implemented it. > b) I think so.The question is what to do when an error is detected... *** Keyboard not present *** Press [F1] to continue. The only I thing I once did, was a small database with maximum and minimum allowed values and preferred defaults for each parameter, which were used to validate the user input during setup, and for sanity checks during startup. The values would be put back to their defaults, if out of limits. Silently. When more than 3 errors, the entire set of parameters would be set to default, which was useful for production. I have had some problems with first generations of EEproms, but not the last 5 years or so, not that I noticed anyway ;) -- Thanks, Frank. (remove 'x' and 'invalid' when replying by email)
Reply by ●July 3, 20042004-07-03
On 2 Jul 2004 21:34:16 -0700, vishalpatil_89@yahoo.co.in (Vishal) wrote:>Hi, Anybody come across continous background checksum tests on >eeprom?? Is it worth doing ??Can be worthwhile in a high-reliability system. Compared to the usual power-on checksum, it has the advantage of testing in the actual execution environment: elevated device temperatures, supply voltage levels and noise affected by active peripherals, etc. In a dialysis machine years ago, I tested ROM and RAM in a background task. The RAM was tested a byte at a time, disabling interrupts briefly while the RAM contents were modified. Assuming the device is on an external bus, you're really testing all of the signals on the bus - decodes, control lines, address and data - so failures can be from problems other than in the memory itself. -- Jim McGinnis
Reply by ●July 3, 20042004-07-03
On Sat, 3 Jul 2004 16:54:25 +0200, the renowned "Frank Bemelman" <f.bemelmanx@planet.invalid.nl> wrote:>"Spehro Pefhany" <speffSNIP@interlogDOTyou.knowwhat> schreef in bericht >news:5mcde01h0d05orbkpc6jga0gd8kq5lrced@4ax.com... >> On 2 Jul 2004 21:34:16 -0700, the renowned vishalpatil_89@yahoo.co.in >> (Vishal) wrote: >> >> >Hi, Anybody come across continous background checksum tests on >> >eeprom?? Is it worth doing ?? >> >> a) I've implemented it. >> b) I think so. > >The question is what to do when an error is detected...>*** Keyboard not present *** Press [F1] to continue.<LOL>>The only I thing I once did, was a small database with >maximum and minimum allowed values and preferred defaults >for each parameter, which were used to validate the user >input during setup, and for sanity checks during startup. >The values would be put back to their defaults, if out of >limits. Silently. When more than 3 errors, the entire >set of parameters would be set to default, which was useful >for production. > >I have had some problems with first generations of EEproms, >but not the last 5 years or so, not that I noticed anyway ;)Loss of calibration data can be the equivalent of a hard failure- there's no obvious default values to set it to. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
Reply by ●July 3, 20042004-07-03
"Spehro Pefhany" <speffSNIP@interlogDOTyou.knowwhat> schreef in bericht news:b9jde05j5hdufdvcles7f89lphk4m7aha9@4ax.com...> On Sat, 3 Jul 2004 16:54:25 +0200, the renowned "Frank Bemelman" > <f.bemelmanx@planet.invalid.nl> wrote: > > >"Spehro Pefhany" <speffSNIP@interlogDOTyou.knowwhat> schreef in bericht > >news:5mcde01h0d05orbkpc6jga0gd8kq5lrced@4ax.com... > >> On 2 Jul 2004 21:34:16 -0700, the renowned vishalpatil_89@yahoo.co.in > >> (Vishal) wrote: > >> > >> >Hi, Anybody come across continous background checksum tests on > >> >eeprom?? Is it worth doing ?? > >> > >> a) I've implemented it. > >> b) I think so. > > > >The question is what to do when an error is detected... > > >*** Keyboard not present *** Press [F1] to continue. > > <LOL> > > >The only I thing I once did, was a small database with > >maximum and minimum allowed values and preferred defaults > >for each parameter, which were used to validate the user > >input during setup, and for sanity checks during startup. > >The values would be put back to their defaults, if out of > >limits. Silently. When more than 3 errors, the entire > >set of parameters would be set to default, which was useful > >for production. > > > >I have had some problems with first generations of EEproms, > >but not the last 5 years or so, not that I noticed anyway ;) > > Loss of calibration data can be the equivalent of a hard failure- > there's no obvious default values to set it to.Yes, for calibration data some redundancy is nice, and auto-repair facility. Or a calibration certificate, on luxury paper and interesting stamps all over it.. or display a nag-screen "calibration required" ;) -- Thanks, Frank. (remove 'x' and 'invalid' when replying by email)
Reply by ●July 3, 20042004-07-03
Vishal wrote:> Hi, Anybody come across continous background checksum tests on > eeprom?? Is it worth doing ??If the integrity requirements for your system indicate that such checking is useful then it is definitely worth doing. As some others have indicated, it can catch problems with bus addressing and/or data shared pathways. The most difficult thing about deciding to use continuous eeprom checksum is what you need to do if you discover a problem. -- ******************************************************************** Paul E. Bennett ....................<email://peb@a...> Forth based HIDECS Consultancy .....<http://www.amleth.demon.co.uk/> Mob: +44 (0)7811-639972 .........NOW AVAILABLE:- HIDECS COURSE...... Tel: +44 (0)1235-811095 .... see http://www.feabhas.com for details. Going Forth Safely ..... EBA. www.electric-boat-association.org.uk.. ********************************************************************
Reply by ●July 3, 20042004-07-03
Vishal <vishalpatil_89@yahoo.co.in> wrote:> Is it worth doing ??The answer to this, like to all truly interesting questions, is: "It depends". In the case at hand, it depends on things like: 1) What's more likely: the EEPROM to fail in operation, but without triggering a watch-dog reset or other safeguards; or your EEPROM checking routine itself to fail, for some unrelated reason? 2) Can you afford the extra CPU load for doing this? 3) Does it pay? Or is it even required, maybe? And remember: be careful asking questions if you can't do anything about the answers. In other words, if the only known cure is worse than the disease, it may not be worth diagnosing the disease. -- Hans-Bernhard Broeker (broeker@physik.rwth-aachen.de) Even if all the snow were burnt, ashes would remain.
Reply by ●July 4, 20042004-07-04
On 2 Jul 2004 21:34:16 -0700, vishalpatil_89@yahoo.co.in (Vishal) wrote:>Hi, Anybody come across continous background checksum tests on >eeprom?? Is it worth doing ??Hi, The most important thing when asking if any sort of error checking is worthwhile, is what do you do if the answer is that there is a problem . If you cannot do something practical/realistic with the answer, then do not bother. Anything that can actually be checked and realistically be used to improve reliability is worthwhile. Regards Anton Erasmus
