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FRAM seems great and I wonder why it's not used more. TI has some MSP430 processors that include it, but when they went to the MSP432 (ARM architecture), they

FRAM seems great and I wonder why it's not used more. TI has some MSP430 processors that include it, but when they went to the MSP432 (ARM architecture), they said something about a process incompatibility. Some ARM or Risc-V processors with FRAM would be great. Any idea what the process issue is? Would you say FRAM is on the decline? Super low powered CMOS ram used to also be a thing, but I haven't seen that in a while either. Added: article mentions flash memory is $15/gbit. I guess that is NOR flash? NAND is way way cheaper, more like $15/terabit. Another question: is it reasonable to say that FRAM automatically implements secure erasure? Like if you overwrite a cell, can you be sure that the old contents are gone? With flash, you have to worry about stuff like sector remapping other the covers. Here's a 4 mbit Adafruit FRAM breakout, out of stock but smaller sizes are available: https://www.adafruit.com/product/4719 https://www.adafruit.com/product/4719 TI MSP430FR5969 development board: https://www.ti.com/tool/MSP-EXP430FR5969 https://www.ti.com/tool/MSP-EXP430FR5969 That is a fancy MSP430 processor with 64KB of FRAM and 2KB of regular ram. The board is $16. The regular ram is I think a little bit faster than the FRAM and good for "infinite" write cycles instead of mere trillions, so I guess you need both. They have a few more of these boards including one with 128KB of FRAM if I remember right.

kens 2y ago
The metal ions from the ferroelectric material can contaminate the silicon production line. I read that they would manufacture the silicon die at one facility (i.e. make the transistors) and then do the rest of the fabrication (the ferroelectric material, top metal, etc.) at another facility to avoid contamination. Maybe that's the process incompatibility that you mentioned. I don't know if FRAM is on a decline or will hold on as a niche product.
- cushychicken 2y ago
  It’s real popular in the niches that use it. Industrial controls systems really seem to love it. I’ve heard that some real fast control systems like to have it as a recovery method to save state in event of major system hiccups.
  - rcxdude 2y ago
    It's also a pretty good debug tool: you can log a trace into a circular buffer in it more or less continuously, then dunno or the contents after a crash or some other failure.
- throwaway81523 2y ago
  Hmm, thanks, I'm surprised those MSP430 cpus aren't more expensive if their fabrication is that complicated. So it sounds like the ARM designs (I guess basically hard macros from ARM Ltd.?) aren't compatible with that type of process. I wonder if a RISC-V design starting with downloaded HDL would be easier. I hope it happens: FRAM is really cool in concept and I've had a few application ideas where it would be great.
  - myself248 2y ago
    I've been wondering if the MSP430's are a single die with the FRAM and the µC on the same process, or if they're co-packaging a "standard" FRAM die made elsewhere.
    - throwaway81523 2y ago
      If the FRAM was a separate die, they could use any CPU they wanted instead of being limited to the MSP430. Added: aha, found the fancier ($20) Launchpad that has 128KB of FRAM and an LCD display: https://www.ti.com/tool/MSP-EXP430FR6989 https://www.ti.com/tool/MSP-EXP430FR6989 This thing was apparently released in 2014. Technology continues to march backwards.

kens 2y ago

The metal ions from the ferroelectric material can contaminate the silicon production line. I read that they would manufacture the silicon die at one facility (i.e. make the transistors) and then do the rest of the fabrication (the ferroelectric material, top metal, etc.) at another facility to avoid contamination. Maybe that's the process incompatibility that you mentioned. I don't know if FRAM is on a decline or will hold on as a niche product.

cushychicken 2y ago
It’s real popular in the niches that use it. Industrial controls systems really seem to love it. I’ve heard that some real fast control systems like to have it as a recovery method to save state in event of major system hiccups.
- rcxdude 2y ago
  It's also a pretty good debug tool: you can log a trace into a circular buffer in it more or less continuously, then dunno or the contents after a crash or some other failure.
throwaway81523 2y ago
Hmm, thanks, I'm surprised those MSP430 cpus aren't more expensive if their fabrication is that complicated. So it sounds like the ARM designs (I guess basically hard macros from ARM Ltd.?) aren't compatible with that type of process. I wonder if a RISC-V design starting with downloaded HDL would be easier. I hope it happens: FRAM is really cool in concept and I've had a few application ideas where it would be great.
- myself248 2y ago
  I've been wondering if the MSP430's are a single die with the FRAM and the µC on the same process, or if they're co-packaging a "standard" FRAM die made elsewhere.
  - throwaway81523 2y ago
    If the FRAM was a separate die, they could use any CPU they wanted instead of being limited to the MSP430. Added: aha, found the fancier ($20) Launchpad that has 128KB of FRAM and an LCD display: https://www.ti.com/tool/MSP-EXP430FR6989 https://www.ti.com/tool/MSP-EXP430FR6989 This thing was apparently released in 2014. Technology continues to march backwards.