FRAM - prices, availability, speed, experience

FRAM? Don't they make oil filters ?:-)

...Jim Thompson

FRAM is made by Ramtron.

FRAM is the non-volitile technology bits and is available in Serial and Parallel.

Serial

-------------------------- Serial FRAM is either in I2C or SPI.... and has very much the same signal functionality as EEPOMs... "almost" drop-in compt to EEPROM.

For an I2C EEPROM part No 24c04.... the equiv Fram part is FM24C04..

For an SPI EEPROM part No 25c04 the equiv FRAM part is FM25c04.... well you get the idea,

In most cases you can pull off a 24cXX and replace it with a FM24cXX etc.... with no or minimal code change... Then you can remove the 10mS delay loops per byte write required for EEPROM.

Bus write speed is 25MHz or more... check the data sheets on the web site above

Parallel

---------------------------- Parallel FRAM is designed to replace battery backup SRAM.... and is indential pinout to SRAMs etc.

Regards Joe

I have used it for several years. My application needs the endurance. Flash memory typically is limited to about 100,000 cycles.

It is available throught distribution in reasonable quantities:

Write time is many times faster, read time is probably limited by bus speed with an I2C device.

Great, just perfect. I see the website is back up, it seemed to be down yesterday and today morning (could be my isp related).

Mouser: ~3 US$ for FM24C64-G, some samples going my way too, I hope.

Anyway, thanks everyone :)

SioL

I have. One thing to remeber is that it works like the old ring core memory. Reads are destructive. Therefore each read involves a write to the memory. Hence, the number of read cycles is also limited!

Core memory data was destroyed by one read. Some of the Ramtron FRAM parts boast "unlimited" Read/Writes, others say 10^12, which is still a lot more than one. I don't think they are multiple-sourced.

Best regards, Spehro Pefhany

Toshiba are making some under license I think (the parallel versions), and these have started to appear in a lot more equipment recently.

Best Wishes

FRAM makes OK oil and air filters. ;-)

In fact even if I read it in a continuous loop all the time this will be > 10 years.

Way past warranty period :)

SioL

plenty.

years.

The limit still renders these devices useless to store a program. I once did make a circuit which starts to run from FRAM, copies the contents into SRAM and then switched the SRAM and FRAM in the address map to execute the software from SRAM (while running at a much higher clock frequency).