Storing variable in perment memory location in LPC2378

Dear sirs
I have one counter variable updating on every 1 second.I have to store that variable in perment memory location.so that I will use that counter after power OFF and ON hardware.but I want value of that variable is last value befour Power OFF the H/W.I want also start counting from last value (not from zero).

Plz suggest me which memory area is sutable to store such variale which is updating at every 1 second.Because it may affect read write cycle life of flash memories.
Here are some memories that I know
1)On chip flash LPC2378
2)On chip RTC battary backup ram of LPC2378
3)External flash
4)External EEPROM.

Thanks&Regards
Parineeta
India

Parents
  • Of the suggested memories, only the battery-backed RAM will not suffer from wear. But the LPC23xx chips are a bit hungry so a supercap will need to be quite large to get longer backup times, and if you switch to silver-oxide or lithium non-chargeable batteries you will have to replace them regularly.

    An EEPROM normally supports an order of magnitude more write cycles than flash. And you may design a scheme where you use 100 memory locations in the EEPROM to scale the life further. Remember that your value is a counter, so the difference between two values is just one - no need for a full 32-bit variable to store each value. Depending on EEPROM type, it may even be that only changes from 0->1 for an individual bit, or from 1->0, may be the only significant wear, in which case you can get even more creative - but such optimizations requires that you contact the chip manufacturer, since such information isn' in the datasheet.

    Note that there are EEPROM-equivalent memories (such as FRAM) that have practically no wear-out count. It may be your simplest solution to the problem - especially since the LPC2378 does not have any built-in EEPROM so your only practical solution to survive a write/second is to pay for hardware.

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  • Of the suggested memories, only the battery-backed RAM will not suffer from wear. But the LPC23xx chips are a bit hungry so a supercap will need to be quite large to get longer backup times, and if you switch to silver-oxide or lithium non-chargeable batteries you will have to replace them regularly.

    An EEPROM normally supports an order of magnitude more write cycles than flash. And you may design a scheme where you use 100 memory locations in the EEPROM to scale the life further. Remember that your value is a counter, so the difference between two values is just one - no need for a full 32-bit variable to store each value. Depending on EEPROM type, it may even be that only changes from 0->1 for an individual bit, or from 1->0, may be the only significant wear, in which case you can get even more creative - but such optimizations requires that you contact the chip manufacturer, since such information isn' in the datasheet.

    Note that there are EEPROM-equivalent memories (such as FRAM) that have practically no wear-out count. It may be your simplest solution to the problem - especially since the LPC2378 does not have any built-in EEPROM so your only practical solution to survive a write/second is to pay for hardware.

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