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ATMega128 -- Difference between flash/eeprom

Im trying to learn microprocessors, and Im a bit confused about flash vs eeprom.

  1. Does my program that I download (via ISP ribbon cable) go into the EEPROM or the FLASH?

  1. Can my user program use the EEPROM at run-time or must it be programmed ahead of time?

  2. How does a bootloader work? (If I store a bootloader in flash, will I need the ISP connector to program the chip anymore? How is it then programmed?)

Thanks! Ben

Reply to
Ben Nguyen
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All executable code in the AVR's is in Flash, so your program goes into it. You can have constant data there also, but accessing it is different from accessing data in the data memories.

The EEPROM is a program-writable memory capable of keeping the data intact when power is off. It is accessed as a peripheral device through a couple of I/O ports, not as an usual memory directly.

The EEPROM is program-writable. Most ISP programmers for AVR can also write it.

Get the Atmel documentation of the chips, your questions have the answers there

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HTH

Tauno Voipio tauno voipio @ iki fi

Reply to
Tauno Voipio

I use the gnu tools, but it certainly will be FLash

user can program it at runtime - and it can be pre-programmed, too.

After reset, the chips looks for a programm in the flash.

Michael

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Reply to
Michael Schuster

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