i need an external nvram to interface with my 89c51 which ic is best to use and readily available?? i tried looking online for navrams, but all i get is EEPROM
i dont want to use EEPROM as a nvram, coz i need to read and write to it a lot...
help pleasE??
A FRAM solution should work great.
But is it the position of parked vehicles you must keep, or the location of the conveyor belts? I would expect that you have enough sensors that you would not need any NV memory to retrieve their current location after a power failure.
If the amount of data to store is small, you can rotate the storage location in a EEPROM memory, greatly increase the number of write cycles you can safely make.
use a FRAM from Ramtron and forget the above.
Erik
"use a FRAM from Ramtron and forget the above."
No, costs are prohibitive for this project.
EEPROM solution is easy to implement and cheaper.
I do know that FRAM is a few cents more than flash; however, what is the cost of the warranty repair when the flash wears out?. I can, of course, not state that your project, the datails of which, I do not know, will risk a flash wear out.
Nevil Bush said, "costs are prohibitive for this project."
Are you on the same project as Bilal Bin Aftab, who started this thread, and specifically stated that he did not want to use EEPROM?
In an automatic car park with lifts and conveyors, can it really be that the cost of one single chip can be "prohibitive" to the budget of the project?!
Bilal Bin Aftab clearly had budget for "Non-Volatile RAM" - how does the cost of FRAM compare to that?
Most of the "Non-Volatile RAM" that I know of relies upon batteries - so they're not going to be cheap, and there's a cost associated with replacing dead batteries...
For a car-park, the cost of a NVRAM chip can be ignored. However, life is complicated when sometimes multiple people from the same company posts in a thread, and somethimes the thread gets hijacked by other people.
Back to a car park - I would very much like such a contraption to have good sensors as extra backup. Especially if it isn't allowed to always return to "home" position after each reset! The oops factor gets less embarasing if it doesn't try to place two cards on top of each other ;)
i want to use as less i/o pins as possible to communicate with the nvram
What about using a serial flash? We're using the MX25L4005A from macronix. The MX25 series has models from 512kbit up to 64Mbit.
See http://www.macronix.com
What would be the advantage over conventional EEPROM?
What would be the advantage over FRAM?
He's already said he doesn't want to use EEPROM, and he doesn't need large capacity...
What would be the advantage over conventional EEPROM? read many, write many? What would be the advantage over FRAM? Only 4 pins instead of many pins?
What would be the advantage over FRAM? Only 4 pins instead of many pins? pins? IIC FRAM and IIC EEPROM uses TWO (uC) pins. SPI FRAM and SPI EEPROM uses 4 (uC) pins. parallel FRAM and parallel EEPROM uses bunches of (uC) pins.