We have an 87c51 system which uses a 93C06 EEPROM to hold configuration data. The units operate 7/24 and on average lost their data every few months. Sometimes ( if not always ) they erase to 0ffh's. I cannot find anything wrong with the micro code.
Has anyone experience hardware errors with these devices?
Thanks, Arthur
Usually something to do with the micro controlling them.. and electrical noise or improper startup and shutdown.
Best regards, Spehro Pefhany
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Watch out for brownouts (voltage dips) small enough to make the -51 misbehave but not low enough to activate the write protection of the EEPROM.
We had a similar problem with a 8051 and EEPROM, and the problem was cured with a brownout detector / reset chip.
It seems that the 8051 family chips start to misbehave and spew all kinds of rubbish on the bus lines just before dying on power starvation.
HTH
Tauno Voipio tauno voipio @ iki fi
Hi, Perhabs you write a lot into the EEPROM and the memory has reached its max number of erasure / programming....
Yvan
********************** YBDesignTauno Voipio a écrit dans le message : eEKOb.24$ snipped-for-privacy@read3.> > We have an 87c51 system which uses a 93C06 EEPROM to hold configuration
Spehro Pefhany schrieb:
Especially power up might cause problems, if CS is not explicitly held inactive (low) until VCC has reached the operating range. If you are interfacing to the '51 directly (particularly CS), this might be an issue. There is a detailed AN on the website of STMicroelectronics about this.
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I recently heard of an inherent weakness of all EEPROMs at low voltage. I'd have to look it up. The essence was to have a fast transition from 0V to operating and back. Especially recommended was a shunt resistor over the power supply to make the power off faster. Eg 1k @ 5V or so.
Rene
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Thank you all for your input.Will try a bit of power supply cycling may reproduce the problem.
Thank you all. I will try some power supply cycling to see if I can reproduce the problem.
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