what are the uses EEPROM?

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hey would someone explain me

"what are the uses EEPROM?"

I know a little that it was used for data storages. But how can I retrieve that data?

"Chill out with Atmel Corp."
- Scud88.

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Are all your previous posts this, uhm, ... interesting?

Regards,
Scott

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Try reading the PDF file for the chip you're programming from cover to cover before you ask a quesiton like that.

-Curiosity may have killed the cat
-But that's why they have nine lives

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the internal EEPROM is usefull for non volatile storage of small amounts of data.

Data such as HoursOnCount, Power Cycles, User Settings, Product serial code etc.

How EEPROM can be accessed is up to you I think. the read and write procedures are really simple.

MY MICROCONTROLLER CAN BEAT THE HELL OUT OF YOUR MICROCONTROLLER /ATMEL

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The EEPROM is handy for storing data that is changed infrequently (e.g. on power-off). It is good for such items as serial numbers, etc. as previously mentioned.

The EEPROM is either accessed via functions and macros in C compilers, or directly via several EEPROM address and read/write registers.

- Dean :twisted:

Make Atmel Studio better with my free extensions. Open source and feedback welcome!

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I use it to store things like default messages to be displayed but which may need to change for different applications, timing parameters i.e. some producst have a piezo buzzer that can be programmed for different beeping speeds or turned steady on, address info for RS485 comms etc.. Pretty much all of these parameters can be accessed/changed by just plugging in a terminal program and resetting the unit, the first few seconds after reset the RS232 input is monitored for a special character, if this is entered then a password is requirered and, if successfull, a small monitor program appears which lets you change the values in the eeprom to customise it for the application. This should give you some ideas how it can be used.

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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Hi, you can use the eeprom for saving your default settings in your application.

Then when you power off and power on later all your user settings
have not been lost.

Pete

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Just be aware that like flash, it can only sustain a certain number of read/write cycles before --- kaput!

I think it is rated for 10,000 in most AVRs? Don't quote me on that though.

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100,000 write cycles on my ancient AT90S8535. Remember that this is _write_ cycles, you can read it as many times as you want.

- Dean :twisted:

Make Atmel Studio better with my free extensions. Open source and feedback welcome!

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They do need to be distributed over the entire array. If you read/write/read.....repeat just the one address that will burn out faster than 100,000 cycles.

If this needs to be qualified then I'm sure someone will update us all with better info.

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True, but you'd usually only read in the EEPROM once at startup.

- Dean :twisted:

Make Atmel Studio better with my free extensions. Open source and feedback welcome!

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Quote:
They do need to be distributed over the entire array. If you read/write/read.....repeat just the one address that will burn out faster than 100,000 cycles.

Is this correct?

The way I read it (but I am far from sure) is that each address in the EEPROM will endure the full number of cycles (100,000 in this case).

Anyone know?

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squiggy wrote:
Quote:
They do need to be distributed over the entire array. If you read/write/read.....repeat just the one address that will burn out faster than 100,000 cycles.

Is this correct?

The way I read it (but I am far from sure) is that each address in the EEPROM will endure the full number of cycles (100,000 in this case).

Anyone know?


That's the way I read it, too.

Four legs good, two legs bad, three legs stable.

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Per AVR101 one has 100,000 writes per address.
Thus the effective endurance for a parameter can be far higher if one uses a circular buffer as described there.
Another method of saving writes, as implemented in CVAVR, is to read the eeprom before writing and only write changed values.

Ralph Hilton