Which is faster: internal EEPROM or External EEPROM?

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Hello, I have a question about the speed of an internal EEPROM vs the speed of external EEPROM connected via I2C, otherwise known as TWI. Which is faster to write to and read from? I think the question is not related to the type of AVR ATMega used, but I am using AVR ATMega16.

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Depends on the type of EEPROM. FRAM write times are very fast compared to the AVR EEPROM.

Jim

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Sort of wonder what data you are talking about if read/write speeds are that important? Usually EEPROM is used for rarely changing configuration like last volume setting or lamp brightness or something. The kind of data sources that produce "fast data" may not the kind of thing it is appropriate to store in EEPROM anyway? Perhaps you need a different memory technology if it is fast/bulk data?

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Mohamed_Ahmed wrote:

Hello, I have a question about the speed of an internal EEPROM vs the speed of external EEPROM connected via I2C, otherwise known as TWI. Which is faster to write to and read from? I think the question is not related to the type of AVR ATMega used, but I am using AVR ATMega16.

 

Surprisingly the type of controller appears to matter.  I guess it is more related to how old a particular chip design is.  Below a summary of the EEPROM write times for different controllers:

atmega16a - 8.5 ms

atmega328p - 3.3 ms

atmega4809 - 2 ms

 

But then as Jim mentioned FRAM is a different story.

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Just googling at random and this:

 

http://ww1.microchip.com/downloads/en/DeviceDoc/22040A.pdf

 

suggests a 5ms write.

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Tell us why it matters to you.

 

Jim

 

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It’s pretty obvious that the internal eeprom is the fastest for reading. I2c isn’t known for its speed.

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Kartman wrote:
I2c isn’t known for its speed.

But with newer I2C specs of up to 3.4MHZ an I2C FRAM with a bus speed of 3.4MHZ is going to be tough to beat.  Of course the hardware driving it needs to meet the bus speeds as well.  But even at 100KHZ to 400KHZ I would give the nod to the FRAM over internal EEPROM

 

The FRAM is considerably more expensive too

 

JIm

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"If you want a career with a known path - become an undertaker. Dead people don't sue!" - Kartman

"Why is there a "Highway to Hell" and only a "Stairway to Heaven"? A prediction of the expected traffic load?"  - Lee "theusch"

 

Speak sweetly. It makes your words easier to digest when at a later date you have to eat them ;-)  - Source Unknown

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB user

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Why the internal and I2C compare , I would look at SPI EEPROM(or FRAM)

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ki0bk wrote:

Tell us why it matters to you.

This

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ki0bk wrote:

 

Tell us why it matters to you.

 

This

This ???  Did you mean this xylophone?

 

Seems like EEPROM writes are measured in some milliseconds, so the bus speed is somewhat "in the noise" .  Obviously for reading, the internal will be "much" faster (on a us scale).

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!