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???
01/15/10 15:28
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#172492 - Reset performance of micro is important!!!
Responding to: ???'s previous message
Uus said:
1. Is there any write cycle (endurance) for BP0 and BP1? Or Is it same with memory endurance of EEPROM itself?

I don't think so. If I was the manufacturer, I would implement each non-volatile Block Protect bit by a larger number of non-volatile memory bits and take the average of all these when reading "its" content. This would make sense as the Block Protect bits are way more often altered than any other non-volatile memory bit.

Uus said:
2. Anybody know why in software protection mode we only can select whole memory or upper area of memory? Why we can not select lower memory (ex. 0000 - 4000H)?

This can have many reasons. For instance to distinguish between a data storage memory that is altered all the time and an important configuration data section which is only altered rarely.

Remember that the reset performance of your micro has a major influence, when thinking about memory security. Don't trust too much the hardware protection of EEPROM, but spend the micro a good reset controller and use the watchdog feature. A MAX1232 providing an external brown-out detection and containig a watchdog is a good choice.

Also, remember that fast glitches on any pin of micro can make the program counter jump to undefined code lines eventually unlocking the software protection. So, your micro must be extremely well shielded against all kind of EMI.

Kai Klaas


List of 10 messages in thread
TopicAuthorDate
EEPROM Protection            01/01/70 00:00      
   No much use            01/01/70 00:00      
      Think about this ...            01/01/70 00:00      
         Robust better than correct            01/01/70 00:00      
            You'll get no argument from me            01/01/70 00:00      
               Always a balance between cost and gains/losses            01/01/70 00:00      
                  No argument here ...            01/01/70 00:00      
            Shielding will not solve?            01/01/70 00:00      
               Magnetic fields are tricky to shield from            01/01/70 00:00      
   Reset performance of micro is important!!!            01/01/70 00:00      

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