| Author |
Message |
Dummy
Guest
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 Posted:
Wed Mar 02, 2005 6:10 am Post subject:
EEPROM checksum error |
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What is the possible cause of EEPROM checksum error?
Could magnetic field corrupt the EEPROM data? Any design guidelines to
prevent this potential failure?
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Luhan Monat
Guest
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| Posted:
Wed Mar 02, 2005 6:10 am Post subject:
Re: EEPROM checksum error |
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Dummy wrote:
| Quote: | What is the possible cause of EEPROM checksum error?
Could magnetic field corrupt the EEPROM data? Any design guidelines to
prevent this potential failure?
|
Eeproms, as far as I know, do not have this feature. Something else
(the programming device) must be making one up and storing it in the
eeprom - somewhere.
You will need to provide more specific information.
--
Luhan Monat (luhanis 'at' yahoo 'dot' com)
"The future is not what it used to be..."
http://members.cox.net/berniekm |
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Ken Taylor
Guest
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| Posted:
Wed Mar 02, 2005 6:10 am Post subject:
Re: EEPROM checksum error |
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"Dummy" <ahkit1021@yahoo.com> wrote in message
news:74bb84c0.0503011834.4ce69faf@posting.google.com...
| Quote: | What is the possible cause of EEPROM checksum error?
Could magnetic field corrupt the EEPROM data? Any design guidelines to
prevent this potential failure?
|
When did this occur? After a long time in circuit? After programming?
Ken
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Dummy
Guest
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| Posted:
Thu Mar 03, 2005 6:10 am Post subject:
Re: EEPROM checksum error |
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"Ken Taylor" <ken@home.nz> wrote in message news:<1bbVd.5787$1S4.626359@news.xtra.co.nz>...
| Quote: | "Dummy" <ahkit1021@yahoo.com> wrote in message
news:74bb84c0.0503011834.4ce69faf@posting.google.com...
What is the possible cause of EEPROM checksum error?
Could magnetic field corrupt the EEPROM data? Any design guidelines to
prevent this potential failure?
When did this occur? After a long time in circuit? After programming?
Ken
|
The range of usage spanned from 6 months to 2 years. EEPROM is used in
mobile radios. All radios are equipped in car or truck. Suspected to
be noise at the supply line that caused the EEPPROM checksum error,
but experiment showed that the noise injected at supply line is
filtered by regulator circuit. Power supply line to EEPROM is
confirmed to be clean regardless the amount of noise exist at main
supply. What could have caused the checksum error? |
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Robert Monsen
Guest
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| Posted:
Thu Mar 03, 2005 1:35 pm Post subject:
Re: EEPROM checksum error |
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Dummy wrote:
| Quote: | "Ken Taylor" <ken@home.nz> wrote in message news:<1bbVd.5787$1S4.626359@news.xtra.co.nz>...
"Dummy" <ahkit1021@yahoo.com> wrote in message
news:74bb84c0.0503011834.4ce69faf@posting.google.com...
What is the possible cause of EEPROM checksum error?
Could magnetic field corrupt the EEPROM data? Any design guidelines to
prevent this potential failure?
When did this occur? After a long time in circuit? After programming?
Ken
The range of usage spanned from 6 months to 2 years. EEPROM is used in
mobile radios. All radios are equipped in car or truck. Suspected to
be noise at the supply line that caused the EEPPROM checksum error,
but experiment showed that the noise injected at supply line is
filtered by regulator circuit. Power supply line to EEPROM is
confirmed to be clean regardless the amount of noise exist at main
supply. What could have caused the checksum error?
|
Make sure you follow all the recommendations of the manufacturer of the
eeprom.
Is the eeprom programmed in the field, or is it just programmed once at
the factory and then used from then on? Is it possible there is a
software error causing this? EEPROMs usually use keyed programming
sequences to prevent inadvertent corruption.
Make sure you lock out interrupts while programming the thing.
--
Regards,
Robert Monsen
"Your Highness, I have no need of this hypothesis."
- Pierre Laplace (1749-1827), to Napoleon,
on why his works on celestial mechanics make no mention of God. |
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Ken Taylor
Guest
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| Posted:
Fri Mar 04, 2005 1:07 am Post subject:
Re: EEPROM checksum error |
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"Robert Monsen" <rcsurname@comcast.net> wrote in message
news:i-qdnTpRspPbI7vfRVn-og@comcast.com...
| Quote: | Dummy wrote:
"Ken Taylor" <ken@home.nz> wrote in message
news:<1bbVd.5787$1S4.626359@news.xtra.co.nz>...
"Dummy" <ahkit1021@yahoo.com> wrote in message
news:74bb84c0.0503011834.4ce69faf@posting.google.com...
What is the possible cause of EEPROM checksum error?
Could magnetic field corrupt the EEPROM data? Any design guidelines to
prevent this potential failure?
When did this occur? After a long time in circuit? After programming?
Ken
The range of usage spanned from 6 months to 2 years. EEPROM is used in
mobile radios. All radios are equipped in car or truck. Suspected to
be noise at the supply line that caused the EEPPROM checksum error,
but experiment showed that the noise injected at supply line is
filtered by regulator circuit. Power supply line to EEPROM is
confirmed to be clean regardless the amount of noise exist at main
supply. What could have caused the checksum error?
Make sure you follow all the recommendations of the manufacturer of the
eeprom.
Is the eeprom programmed in the field, or is it just programmed once at
the factory and then used from then on? Is it possible there is a software
error causing this? EEPROMs usually use keyed programming sequences to
prevent inadvertent corruption.
Make sure you lock out interrupts while programming the thing.
--
Regards,
Robert Monsen
All that good stuff.... |
Also, are these two-way radios? Do the EEPROM's get altered during normal
use, in which case is it possible RF is causing problems?
Ken |
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Pooh Bear
Guest
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| Posted:
Sat Mar 05, 2005 6:10 am Post subject:
Re: EEPROM checksum error |
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Dummy wrote:
| Quote: | What is the possible cause of EEPROM checksum error?
Could magnetic field corrupt the EEPROM data? Any design guidelines to
prevent this potential failure?
|
*What* checksum ? How do you calculate 'your' checksum ?
What type of Eeprom ? 24Cxx family for example ?
Far too little info supplied to meaningfully respond.
Graham |
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Pooh Bear
Guest
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| Posted:
Sat Mar 05, 2005 6:10 am Post subject:
Re: EEPROM checksum error |
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Robert Monsen wrote:
| Quote: | Dummy wrote:
"Ken Taylor" <ken@home.nz> wrote in message news:<1bbVd.5787$1S4.626359@news.xtra.co.nz>...
"Dummy" <ahkit1021@yahoo.com> wrote in message
news:74bb84c0.0503011834.4ce69faf@posting.google.com...
What is the possible cause of EEPROM checksum error?
Could magnetic field corrupt the EEPROM data? Any design guidelines to
prevent this potential failure?
When did this occur? After a long time in circuit? After programming?
Ken
The range of usage spanned from 6 months to 2 years. EEPROM is used in
mobile radios. All radios are equipped in car or truck. Suspected to
be noise at the supply line that caused the EEPPROM checksum error,
but experiment showed that the noise injected at supply line is
filtered by regulator circuit. Power supply line to EEPROM is
confirmed to be clean regardless the amount of noise exist at main
supply. What could have caused the checksum error?
Make sure you follow all the recommendations of the manufacturer of the
eeprom.
Is the eeprom programmed in the field, or is it just programmed once at
the factory and then used from then on? Is it possible there is a
software error causing this? EEPROMs usually use keyed programming
sequences to prevent inadvertent corruption.
Make sure you lock out interrupts while programming the thing.
|
The serial interface is timing tolerant IME. Never seen false data as a result of background
interrupts.
Graham |
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Harold Ryan
Guest
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| Posted:
Sat Mar 05, 2005 8:46 pm Post subject:
Re: EEPROM checksum error |
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Checksum is just the addition of each byte of data. At the end of the file,
another byte or word is added that will total all of the bytes to zero. If
any of the bytes are corrupt, the total sum of all the bytes will not be
zero. A loose wire or strong magnetic field may cause this problem.
Harold
"Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:422913CA.21AE9381@hotmail.com...
| Quote: |
Dummy wrote:
What is the possible cause of EEPROM checksum error?
Could magnetic field corrupt the EEPROM data? Any design guidelines to
prevent this potential failure?
*What* checksum ? How do you calculate 'your' checksum ?.
What type of Eeprom ? 24Cxx family for example ?
Far too little info supplied to meaningfully respond.
Graham
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Spehro Pefhany
Guest
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| Posted:
Sat Mar 05, 2005 9:23 pm Post subject:
Re: EEPROM checksum error |
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On 2 Mar 2005 21:05:59 -0800, the renowned ahkit1021@yahoo.com (Dummy)
wrote:
| Quote: | "Ken Taylor" <ken@home.nz> wrote in message news:<1bbVd.5787$1S4.626359@news.xtra.co.nz>...
"Dummy" <ahkit1021@yahoo.com> wrote in message
news:74bb84c0.0503011834.4ce69faf@posting.google.com...
What is the possible cause of EEPROM checksum error?
Could magnetic field corrupt the EEPROM data? Any design guidelines to
prevent this potential failure?
When did this occur? After a long time in circuit? After programming?
Ken
The range of usage spanned from 6 months to 2 years. EEPROM is used in
mobile radios. All radios are equipped in car or truck. Suspected to
be noise at the supply line that caused the EEPPROM checksum error,
but experiment showed that the noise injected at supply line is
filtered by regulator circuit. Power supply line to EEPROM is
confirmed to be clean regardless the amount of noise exist at main
supply. What could have caused the checksum error?
|
What kind of EEPROM? Data corruption in EEPROMs is not uncommon-
caused directly by electrical noise, or by faulty design of the
controlling microprocessor system, either wrt to EMI or power supply
supervision. Redesign to decrease EMI susceptibility and PS issues,
and then (and ONLY then) tweaks to add redundancy to the non-volatile
storage can reduce the issue to insignificance even for large
quantities of units in challenging applications.
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 |
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Pooh Bear
Guest
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| Posted:
Mon Mar 07, 2005 6:10 am Post subject:
Re: EEPROM checksum error |
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Harold Ryan wrote:
| Quote: | Checksum is just the addition of each byte of data. At the end of the file,
another byte or word is added that will total all of the bytes to zero. If
any of the bytes are corrupt, the total sum of all the bytes will not be
zero. A loose wire or strong magnetic field may cause this problem.
Harold
|
I'm broadly familiar with this thanks. I'm less familiar with why Eprom
programmers of old seemed to produce different checksums according to
manufacturer.
The OP still hasn't explained *what checksum* he's talking about under what
conditions.
Can he even validate the file ?
Graham |
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Lord Garth
Guest
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| Posted:
Mon Mar 07, 2005 12:24 pm Post subject:
Re: EEPROM checksum error |
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"Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:422BE817.F051E6A@hotmail.com...
| Quote: | Harold Ryan wrote:
Checksum is just the addition of each byte of data. At the end of the
file,
another byte or word is added that will total all of the bytes to zero.
If
any of the bytes are corrupt, the total sum of all the bytes will not be
zero. A loose wire or strong magnetic field may cause this problem.
Harold
I'm broadly familiar with this thanks. I'm less familiar with why Eprom
programmers of old seemed to produce different checksums according to
manufacturer.
The OP still hasn't explained *what checksum* he's talking about under
what
conditions.
Can he even validate the file ?
Graham
|
Maybe a CRC was used rather than a checksum. How old is the code in the
EPROM? |
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Dummy
Guest
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| Posted:
Tue Mar 08, 2005 12:25 pm Post subject:
Re: EEPROM checksum error |
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Pooh Bear <rabbitsfriendsandrelations@hotmail.com> wrote in message news:<422BE817.F051E6A@hotmail.com>...
| Quote: | Harold Ryan wrote:
Checksum is just the addition of each byte of data. At the end of the file,
another byte or word is added that will total all of the bytes to zero. If
any of the bytes are corrupt, the total sum of all the bytes will not be
zero. A loose wire or strong magnetic field may cause this problem.
Harold
I'm broadly familiar with this thanks. I'm less familiar with why Eprom
programmers of old seemed to produce different checksums according to
manufacturer.
The OP still hasn't explained *what checksum* he's talking about under what
conditions.
Can he even validate the file ?
Graham
|
The EEPROM will be programmed in factory before shipping out to
customer.
Everytime when radio is turned on, checksum will be verified. Checksum
error will occur when any bytes are corrupted in the EEPROM. If data
corrupted during radio ON, any checksum error won't be detected until
the next radio turned OFF and ON cycle.
The corrupted bytes are at random EEPROM address.
Some of the parts could be recovered after re-programming while some
could not. For those parts which damaged permanently, failure analysis
showed cell overwritten. Trying to inject some noises to EEPROM data
or supply line while performing write operation could cause checksum
error. But all the voltages supplied to EEPROM are clean when in
normal use. The filter and regulator have taken care of the noises. So
it's not right to point to the noise as the culprit.
Most of the radios failed after being in the field from 6 months to 2
years. |
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Robert Monsen
Guest
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| Posted:
Tue Mar 08, 2005 12:54 pm Post subject:
Re: EEPROM checksum error |
|
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Dummy wrote:
| Quote: | Pooh Bear <rabbitsfriendsandrelations@hotmail.com> wrote in message news:<422BE817.F051E6A@hotmail.com>...
Harold Ryan wrote:
Checksum is just the addition of each byte of data. At the end of the file,
another byte or word is added that will total all of the bytes to zero. If
any of the bytes are corrupt, the total sum of all the bytes will not be
zero. A loose wire or strong magnetic field may cause this problem.
Harold
I'm broadly familiar with this thanks. I'm less familiar with why Eprom
programmers of old seemed to produce different checksums according to
manufacturer.
The OP still hasn't explained *what checksum* he's talking about under what
conditions.
Can he even validate the file ?
Graham
The EEPROM will be programmed in factory before shipping out to
customer.
Everytime when radio is turned on, checksum will be verified. Checksum
error will occur when any bytes are corrupted in the EEPROM. If data
corrupted during radio ON, any checksum error won't be detected until
the next radio turned OFF and ON cycle.
The corrupted bytes are at random EEPROM address.
Some of the parts could be recovered after re-programming while some
could not. For those parts which damaged permanently, failure analysis
showed cell overwritten. Trying to inject some noises to EEPROM data
or supply line while performing write operation could cause checksum
error.
|
You say they are preprogrammed, but this implies that you are writing
them during normal operation. Which is it?
| Quote: | But all the voltages supplied to EEPROM are clean when in
normal use.
|
^ Famous last words. :)
The filter and regulator have taken care of the noises. So
| Quote: | it's not right to point to the noise as the culprit.
Most of the radios failed after being in the field from 6 months to 2
years.
|
If the eeproms aren't being reprogrammed in the field during normal use,
then a software error is unlikely, unless the magic write sequence is
stumbled upon during a freak crash. If they *are* being reprogrammed
(ie, you are saving some value when the user retunes the radio) then
I'll again say software. I'm telling you, lock out those interrupts!
The other possibility is a bad batch of eeproms. This is fairly
unlikely, but not without precedent*. Attempt to correlate the bad ones
with some lot. Talk to the manufacturer, and ensure that they don't have
a 'known' problem. Also, I wouldn't reuse the corrupted ones just
because you managed to program them. I'd swap them out as soon as practical.
* A company I used to work for decided to save 10 cents a ram chip and
forgo individual testing of the chips by the manufacturer. Sadly, it
turned out that those chips were bad 5 to 10 percent of the time. They
were selling high availability purple ethernet switches for hundreds of
thousands of dollars each. The engineer responsible was of course
promoted to VP, and given vast new responsibilites.
--
Regards,
Robert Monsen
"Your Highness, I have no need of this hypothesis."
- Pierre Laplace (1749-1827), to Napoleon,
on why his works on celestial mechanics make no mention of God. |
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Spehro Pefhany
Guest
|
| Posted:
Tue Mar 08, 2005 8:20 pm Post subject:
Re: EEPROM checksum error |
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On 7 Mar 2005 22:25:27 -0800, the renowned ahkit1021@yahoo.com (Dummy)
wrote:
| Quote: |
The EEPROM will be programmed in factory before shipping out to
customer.
Everytime when radio is turned on, checksum will be verified. Checksum
error will occur when any bytes are corrupted in the EEPROM. If data
corrupted during radio ON, any checksum error won't be detected until
the next radio turned OFF and ON cycle.
The corrupted bytes are at random EEPROM address.
|
Okay. As I suspected.
| Quote: | Some of the parts could be recovered after re-programming while some
could not. For those parts which damaged permanently, failure analysis
showed cell overwritten. Trying to inject some noises to EEPROM data
or supply line while performing write operation could cause checksum
error. But all the voltages supplied to EEPROM are clean when in
normal use.
|
Well, what about "abnormal" use, say something that might happen only
rarely? Are you claiming that the supply voltage on these parts was
maintained at 5.0V +/- 5% constantly, never straying lower or higher,
from factory to failure? And noise injected from the supply or other
pins could cause the micro's PC to point to random bits of code.
| Quote: | The filter and regulator have taken care of the noises. So
it's not right to point to the noise as the culprit.
|
I sure don't think you can conclude that.
| Quote: | Most of the radios failed after being in the field from 6 months to 2
years.
|
My original comments definitely apply to this situation. Can you post
a link to the schematic of the power supply, micro and EEPROM?
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 |
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