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Hi , We have been using 68hc11 for many of our products. Recently we have identified a problem where there is a memeory corruption.The code is stored in EEPROM and also has some calibration data.The system works fine in most of the typical use,But recently we conducted vibration test and later found that the code was corrupted in EEPROM? But there is no problem in EEPROm cuz we can download the code again and it works fine. The problem happens only when we vibrate the unit. Any thoughts or suggestions? What would be a possible suspect? Powersupply or EEPROM? or anything else? Thanks anees [Non-text portions of this message have been removed]

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Anees, sorry for the elementary questions here: are you using a socket for your HC11 ? Connectors ? Cabinet shielding ? Sounds like something mechanical ... An idea of how much vibration ( acceleration) ? I had LOTS of problems with PLCC-52's of prime quality brands and also problems with the quality of the contact between chip leads and socket pins . Ceramic package is a pain in the a... ( no way to keep leads stright , but if you are talking production you are not using ceramics for sure ). Regards, Roberto Guillermo Berner Boolean General ICQ 119529928 54 11 4308 3500 54 11 4308 3700 15 5122 6095 ----- Original Message ----- From: Anees Hameed To: Sent: Friday, October 25, 2002 3:33 PM Subject: [m68HC11] memory corruption Hi , We have been using 68hc11 for many of our products. Recently we have identified a problem where there is a memeory corruption.The code is stored in EEPROM and also has some calibration data.The system works fine in most of the typical use,But recently we conducted vibration test and later found that the code was corrupted in EEPROM? But there is no problem in EEPROm cuz we can download the code again and it works fine. The problem happens only when we vibrate the unit. Any thoughts or suggestions? What would be a possible suspect? Powersupply or EEPROM? or anything else? Thanks anees [Non-text portions of this message have been removed] Yahoo! Groups Sponsor ADVERTISEMENT To unsubscribe from this group, send an email to: Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. [Non-text portions of this message have been removed]

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There is also the factor of power supply condition. I believe the pink book talks about carefully maintaining your power supply, and controlling reset when the system powers on and off. If the power supply is unstable enough, the reset pin should be pulled low to prevent corruption of the internal memory. As Roberto mentions, you should check your socket (if you're using one) to make sure that the chip is firmly reatined during the vibration. If you have the surface mount version of the PLCC socket, you should be especially careful - from my own experience they are very difficult to get soldered consistently, and since there is less mass to the socket, it doesn't maintain form as well.... If the chip vibrates in the socket, you could be getting intermittent power, and corruption this way. You should also check your power supply components. If something is shaking loose or is intermittent during the vibration, your power supply could brown out enough to cause memory corruptions. This would include any and all cabling and interconnects. If you have a way to monitor your power supply and/or the address/dfata bus during the test, you will likely find the cause very quickly. If you're using an external EEPROM, see if it has a write-protect feature, and find a way to use it. Unstable power supply conditions can cause the write enable and chip enable lines to go the wrong way at the wrong time, giving random corruption of the memory. Write-protection takes some overhead for changing code in the field, but it can be invaluable. -Brian --- Boolean General <> wrote: > Anees, sorry for the elementary questions here: are you using a > socket for your HC11 ? Connectors ? Cabinet shielding ? Sounds like > something mechanical ... An idea of how much vibration ( > acceleration) ? I had LOTS of problems with PLCC-52's of prime > quality brands and also problems with the quality of the contact > between chip leads and socket pins . Ceramic package is a pain in the > a... ( no way to keep leads stright , but if you are talking > production you are not using ceramics for sure ). > > Regards, > > Roberto Guillermo Berner > Boolean General > > ICQ 119529928 > 54 11 4308 3500 > 54 11 4308 3700 > 15 5122 6095 > > ----- Original Message ----- > From: Anees Hameed > To: > Sent: Friday, October 25, 2002 3:33 PM > Subject: [m68HC11] memory corruption > Hi , > We have been using 68hc11 for many of our products. Recently we > have > identified a problem where there is a memeory corruption.The code > is stored > in EEPROM and also has some calibration data.The system works fine > in most > of > the typical use,But recently we conducted vibration test and later > found > that the code was corrupted in EEPROM? But there is no problem in > EEPROm cuz > > we can download the code again and it works fine. > The problem happens only when we vibrate the unit. > Any thoughts or suggestions? What would be a possible suspect? > Powersupply > or EEPROM? or anything else? > Thanks > anees > > [Non-text portions of this message have been removed] > Yahoo! Groups Sponsor > ADVERTISEMENT > > > To unsubscribe from this group, send an email to: > > > __________________________________________________

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