Quote:
the calculator can only be flashed a few 1000 times...
The endurance spec is 10,000 times, with 10 year retention. This means that at 10,000 writes, the flash will still give valid data at all combinations of the chip's specifications, such as low voltage at low temperature, low voltage at high temperature, high voltage at low temperature, and at all process corners. And still meet the 10 year data retention specification. It doesn't mean that it will fail on the 10,001st write.
In other words, there's a good chance that your calculator can be flashed a lot more than 10,000 times, because you probably only operate it at room temperature, and not at any temperature extremes (or high voltage extreme), and because Atmel is probably fairly conservative in specifying the endurance at 10,000, but if it does happen to fail on the 10,001st write, it's your problem and not Atmel's.
If you were using a calculator based on this part for development (rather than a simulator), it would take quite a while to try 10,000 code images. The calculator isn't that expensive, so even if it does fail on the 10,001st write, you can buy a new one, and not feel like you didn't get your money's worth for the first one.
I'm doing some firmware development now on a different vendor's ARM chip. I don't have a simulator. I might work 12 hours in a day on it, but I don't think I've ever reflashed it more than about 50 times in a day, and usually not nearly that many.