Suggestions for Non Volatile Memory
Suggestions for Non Volatile Memory
(OP)
Here is the second question. For the project I will require some non volatile memory for temporary storage while the unit is unpowered. I designed the board using a Dallas-Maxim part, but it is only a byte wide part. Since just about every device on the system is 16 bits wide and the processor isn't byte addressable, this becomes a real inconvenience. The problem is that in x16 sizing, or with two devices in parallel, Dallas chips get very expensive.
The present device on the board is only 32K x8, but it does have a real time clock which is a plus. If I use a different device, I will need to use a clock chip too, which isn't too big of a deal.
I was wondering if anybody has any suggestions or recommendations for NV ram that they have had a good experience with?
The present device on the board is only 32K x8, but it does have a real time clock which is a plus. If I use a different device, I will need to use a clock chip too, which isn't too big of a deal.
I was wondering if anybody has any suggestions or recommendations for NV ram that they have had a good experience with?





RE: Suggestions for Non Volatile Memory
RE: Suggestions for Non Volatile Memory
Would you be willing to elaborate please?
RE: Suggestions for Non Volatile Memory
http://en.wikipedia.org/wiki/Flash_memory
RE: Suggestions for Non Volatile Memory
TTFN
RE: Suggestions for Non Volatile Memory
I am also hesitant to go with anything that will require special access handling because the memory chips connect to the processor's external interface very cleanly and the only thing I have to do is make sure the wait states for that address range are within the timing paramaters of the memory.
It looks like TI (not reknown for memory), Maxim, and Simtek (aquired ZMD) make a form of battery backed ram, so the choice is slightly limited.
I also received a suggestion to look at Ramtron, which I understand used to have issues associated with very limited rewrites, that apparently have been solved. It is limited in size, about 32K x8 but a $10 per device is about half the price of the battery memories. I was wondering if anyone has had any experience with these devices?
RE: Suggestions for Non Volatile Memory
The key is that you only update the memory when it changes.
RE: Suggestions for Non Volatile Memory
RE: Suggestions for Non Volatile Memory
Many companies have this one.
SPI very easy to use. You can bit bang at 10MHz or use your processor's SPI port.
It has a chip select so you can use multiple ones.
If you're into I2C (yuck) you can get 16bit I think, and 128K X 8
http://w
RE: Suggestions for Non Volatile Memory
Anything else will be a lot slower, but bang for your buck and minimal board space, the serial EEPROMs will be hard to beat.
RE: Suggestions for Non Volatile Memory
My initial thought was to use two Dallas chips, but I am looking for alternatives that would be less expensive. I hear that Simtek and Ramtron are about 1/3 to 1/4 the price of Dallas_Maxim, though I don't have experience with either of them to personally attest to their reliablity.
Using a serial eeprom is a good suggestion, though.