I need 512k x 8 storage space which can be done with a single
29C040A Flash. The quoted figure for Flash is > 10,000 write
cycles. I "might" have a look at battery backed-up SRAM, I've a
few 8M TSOPs, but truly NV is preferable

Does the endurance refer to the number of times a bit changes
state or the number of times that bit is written to, whether it
changes state or stays the same ? As the PIC's Flash memory
can be re-programmed ~1,000 times that makes me wonder.
Could that be Microchip's definition of > 10,000, ie 14 bits x 1,000 ?

If, (as I think because the 29C040A data doesn't say otherwise),
it means each sector can be over-written 10,000 times however
the contents change, then I'm OK, else I'll go with 8 x 24C512
EEPROM (> 10,000,000 writes but more board and 3x the price)

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