FRAM Ramtron FM24C512 / FM24C256

[This N°9]

Looking for some kind of serial accessible RAM, I found someting interesting. It's a non-volatile RAM device (Ferroelectric technology).

features:

- up to 512Kbits (4, 64, 256 also available) storage

- no delays on writes (!)

- up to 1MHz clock frequency

- two-wire serial communication (SC / SD)

- two address pins (up to 4 devices)

- 10 billion (10^10) write/read cycle life endurance (!)

It's a bit more expensive than a bankstick  with the same size (ca. 15$ / 10eur for a 256Kb @ farnell), and seems to be harder to get. For the 512Kb I only found the datasheets so far, and the 256Kb I only found @ farnell.

Maybe somebody knows more about it, or even has experiences with this device type. I will study it a bit more, and check for other sources.

I attached the datasheet for everbody who likes to know more.

EDIT: also available here (USA), much cheaper than in europe:

http://www.futureelectronics.com/en/technologies/semiconductors/memory/fram-mram/Pages/8772774-FM24C512-G.aspx?CrossPart=

even cheaper (bulk order):

http://www.onlinecomponents.com/buy/RAMTRON/FM24C512-G/

fm24c512_datasheet.pdf

fm24c512_datasheet.pdf

[This N°9]

I read the specs of both the bankstick 24LC512 and the Ramton FM24C512 (atention! there are devices with the same type name that are EEProm devices, not ferroelectric!).

I must say I'm absolutely excited! This is THE thing! The only negative aspects may be the fact that it is only available as SMD, and that there are only 2 device address pins. But this is exactly what I need for the sequencer I plan, I can read and write randomly from it at both full speed without any delays, and it's very enduring. Life extending stuff could be done, but is absolutly not necessary. This is a quote from the spec:

"Even at 30 accesses per second to the same segment, 10 years time will pass before 10 billion endurance cycles occur".

I suppose until then we will have some holographic storage or something..  :D

The protocoll is different from the 24LC512, but very handy. It's also based on IIC, max. clock frequency is 1MHz. I'll order some FM24C512 from onlinecomponents.com (they ship internationally), and write a driver for it. Hardware interface is the same as for the banksticks, they could even be mixed in the same chain, using either the regular bankstick functions or the FRAM driver functions.

Subsequent reads/writes are possible and don't differ from single reads, so I will build stuff to have most flexibility.

I will also add a multiplex feature, which can be used with a dual 4-channel analog multiplexer like the 74HC4052. The pins used to multiplex will be configurable, default will be RC4 / RC5. So 4 chains can be used in parallel, which gives you 1MByte FRAM storage. The SDcard driver can be used in parallel with default Port C.

[stryd_one]

Sounds interesting :)

I have a driver here for parallel SRAM (628512 etc) shared with the LCD data buss if you're really hungry for big fast storage...

[This N°9]

The speed will be sufficient for my needs, and it doesnt matter if I read a single byte or a series of them. So no more buffering needed on reads! I can just test if I need more data, if not, I close the stream. And.. writes will be performed the same speed as reads, no delays, full clock speed! 1MB is enough for one "song", I will use the SDcard to stuff the current song to a bigger storage, the FRAMs will be my working-space.

The FRAM technology seems to be quite new, it uses not floating gate transistors, but "cells" that can keep potentials like a condesator, but some kind of piezzo-like cristal material is used.

[This N°9]

I just received the IC's and built a PCB with 4 of them, I used some "SMD wrappers" to mount the IC's (This rellay costs nerves if you don't have flux on hand, I've got to learn design/etch PCBs!)

Next step is to write a driver in ASM for these, this will cost me some more nerves because this is my first ASM project  :)

Enjoy the pictures

[stryd_one]

Wow, way to jump right in the deep end... of the pool with sharks in it... with fricken laser beams attached to their heads... and bees in their mouth, and when they bite you, they shoot bees.

:D

Good stuff!!

[This N°9]

Wow, way to jump right in the deep end... of the pool with sharks in it... with fricken laser beams attached to their heads... and bees in their mouth, and when they bite you, they shoot bees.

Don't worry, I'm quite used to that... my regular ways  ;)