im curious.. should it effectively last forever if handled with care? or can games only be flashed onto the memory so many 1000's times?
ed64 flash has 100 000 guaranted rewrite cycles by flash datasheet. you can reflash game 5 times every day for a 55 years
You'll have to sit around all day reflashing probably to ever reach the end of the Flash's lifespan atleast in theory.
Something to consider though is that EverDrives use FRAM; FRAM is not only write-destructive, it's also read-destructive. Since it's used in lieu of SRAM, any games which doesn't double-buffer save variables could really wear out the memory. On the SNES it's also possible that games execute code out of SRAM so in theory a game could use up 3.5 M accesses/second. FRAM endures 100 trillion accesses for the highest chip grade so it would only take 28571428 seconds or less than one year if you left such a game running straight. The standard grade being sold now only endures *1 trillion* so that would only take a few days to wear out if you tried! Old old FRAM's endurance is only in the millions or billions, but I don't think any of those chips are used.
even if such games exist, then snes should read/write same byte with 3.5mhz rate, but it is just impossible, even if some code was loaded to save ram, because any program loop has at least few instruction plus any instruction need few cpu cycles. so in worst case it will be few kilo cycles per second. by the fact, when i develop snes cart, i used led on the cart for indicate access to sram and all tested games touch the sram only when they load or save something
That's true, but 65XXX architectures have 1 bus access / CPU cycle. clc here: bcc here Would kill the memory very fast, just pointing it out. I'm not so sure there are trillion+ accesses per byte either, it might be per whole device since Ramtron doesn't specify and perhaps the row/column decoders wear out many cells at once.
bus acces 1 cycle, but then need few cycles for execute instructions i must accept that code in save memory could be dangerous if 1tril cycles limit for whole device. probably i will lock acces to sram for such games if i will found them once, but i really not think that any games trying to load code to sram or something like like this. currently i use new fm18w08 where 100tril guarantied cycles, but even old carts with old fm1808, where 1tril cycles life time, never not back to me with dead ramtron. sometimes new ramtron chip from box could be defective and it is the main problem on this moment, by this reason i made some equipment for test them
For curiousitys sake: Why did you use FRAM at all? Wouldnt it be easier/better, to just use SRAM and Battery?
not easier and not better. sram is cheaper, and on the practic it is the only advantage of sram. i not like battery solutions
Flash based Everdrives use an extremely low density 8 MB SLC NOR flash with over 100,000 rewrite cycles. Totally different from the extremely high density 25nm and smaller MLC NAND flash with multi GIGAbytes per chip used in SSDs and thumb drives that have less than 10,000 rewrites (and even those will last a decade with constant writing at the max speed due to wear leveling algorithms and sufficient slack space). MRAM/FRAM should have virtually unlimited rewrites despite being rated with a hard number. There is no floating gate insulator being deteriorated by hot electron tunneling as flash does.
That could always be put to the test by writing a Genesis or SNES ROM that constantly rewrites the SRAM space.
Yea if your comfortable leaving your console powered up for years:lol: If it lasts longer than an xbox 360, I'm happy:flamethrower:
My NES has already outlasted two Xbox 360 consoles will will likely outlast the one I have now. This is the nature of the NES's simple design that can actually be repaired unlike newer consoles that when something goes wrong they tend to be doomed or too costly to bother repairing.
totally agree unfortunately modern consoles require being more complicated, at least we can fix them to an extent, be nice if the 360 had worked when it left the production line the first time, alas it didnt
360's use ball-pin-grid-array processors. They will never be reliable until they switch, to something that doesn't chip creep. I like Microsofts policy that they will give life time warranty for rrod's, and then they come out with a new generation....with the same problem...and call it a different error.:lol:
They didnt give life time warranties, it was 3 years. BGA has been used for years and do not fail like the xbox has been doing. Its a combination of bad processor placement (as in, location on the board) and the need to switch to lead free solder.
