New type of memory chip...

bpowell

Senior Member
I saw this new type of memory from Microchip Serial EERAM which looks pretty cool.

Yon can read/write to it using I2C as you normally would...but without limits...if the chip loses power, it quickly writes the contents of its ram to EEPROM (rated for 1M writes) before shutting down...and automatically recalls that data from EEPROM to RAM on power-up...

I can't think of a project where I'd need this...but it's nice to know the tech is out there for more frequent memory writes...at $0.80 a pop, it's cheaper than FRAM if you have an application that requires frequent writes that need to be saved.
 

westaust55

Moderator
An alternative that may be worthwhile where a lot of NV RAM is required.

Does need selection for supply voltage range - separate part for 2.8 to 3.3 V and 4.5 to 5.5 V.

If one has a project also needing an RTC chip the DS1307/DS1338 has 57 bytes of battery backed/NV RAM and the DS3232 has 236 bytes that can be considered.
But yes, if one needs 512 bytes or 2048 bytes, then these new parts may be worthy of consideration.

Currently Mouser sell
24LC04 EEPROM for around $0.60
47C04 NV EERAM for around $1.50
So one does need to check on pricing
And consider how often one will really be writing to the Memory.
 

hippy

Technical Support
Staff member
It does look like an interesting device and suited to cases where one wants external non-volatile memory which may get frequently updated.

The full datasheet is here -

http://ww1.microchip.com/downloads/en/DeviceDoc/20005371C.pdf

It is a little more complicated than a standard I2C EEPROM. Standard EEPROM read and write functionality is available through the familiar $Ax I2C Device Address, and there is another $3x Device Address which allows configuration and control of the device.

Though it seems it could be a drop-in for existing I2C EEPROM, there does seem to be limitations that A0 must be 1, the traditional EEPROM must have been at Device Address $A2, auto-store cannot be used without a Vcap, and memory may be corrupted if power fails while a manual-store is being executed.

Although there are unlimited read and writes for the RAM part, there is a maximum of 1M auto-saves or manual-saves, though it does not appear to save if the data has not changed so it is not necessarily limited to 1M power-offs.
 
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