Storing Calibration Data

It depends on the programmer. Some only write locations that contain a zero bit. I.E. not 0xff or 0x3fff.

Mike.

That would make sense, there's no need to overwrite data thats already cleared

Pommie said:

It depends on the programmer. Some only write locations that contain a zero bit. I.E. not 0xff or 0x3fff.

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Mine does (and always has), which is what helps make it the fastest programmer software. However, I don't know if 'writing' all ones actually counts as doing a write or not?, as nothing is changed by it.

I think it's the same with flash, but with eeprom a write of any data (even the same data back) will have to erase the block first, unless the compiler or the code itself checks to see if the data is the same before it writes.

Sceadwian said:

I think it's the same with flash, but with eeprom a write of any data (even the same data back) will have to erase the block first, unless the compiler or the code itself checks to see if the data is the same before it writes.

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You can write a word over another one, but it will only affect one's that change to zero's, you can't change zero's to one's without erasing it - same applies to EPROM as well.

Much 'Flash' is actually just EEPROM any way, Atmel started calling their EEPROM devices Flash (as it's a popular buzz word), and everyone else followed suite - although there are some Flash devices now.