Hugo Holden did a quick calculation using his logic analyzer, and the FRAM datasheet, and came up with the following:
Ramtron claims the FM16W08 cells should operate for 10^14 R/W cycles.
The life is apparently related to temperature, and supply voltage. the 10^12 number is at max temperature, and 5.5V, tek runs the
^ 10^14
logic at 5V and much cooler..
Given that the FRAM is like the old magnetic core memory, in that reading requires destroying the data bit, and rewriting it, every read or write cycle wears the FRAM the same.
Hugo calculated that the 2465 accesses RAM at a 100KHz rate, and that if the same cell was accessed at that rate, 24/7, it would last 31 years.
Hugo further calculated that at the 6802's 100KHz RAM R/W rate, operating 5 days per week, and 8 hours per day, it should last 130 years.
Will it? Nobody knows, FRAM's haven't been around very long.
It is a grand experiment that a few of us are doing.
But seriously, your scope needs calibrating every 5-10 years.
-Chuck Harris
Raymond Domp Frank wrote:
On Fri, Oct 12, 2018 at 04:34 PM, Chuck Harris wrote: Hi Chuck, You're writing:
99% (hopeless exaggeration) of the NVRAM is not calibration constants, but rather operating memory for the 6802. That memory holds stuff like the interrupt pointers, stack, heap, and data areas for the program.
Knowing the limited number of write cycles that an FRAM is capable of: Have you ever done any calculations or measurements re. the lifetime to be expected for these devices in a 2445(X) or 2465(X)? Since these devices do not do any wear leveling, results could be worrying/disappointing.
