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lock bits
Posted by: Alexij ()
Date: April 13, 2014 02:10PM

Hi!
thanks a lot for PonyProg! Very intuitive interface.
As I'm a novice with AVR I need an advice smiling smiley
I need to make a copy of the Atmega8 chip to restore an old unsupported device (I have one more "alive"winking smiley.
With PonyProg I've managed to download FLASH & EEPROM content, but when I've checked the state of the fuses I was amused: Lock1 and Lock2 fuses were
"up" (marked with v). So, how could I read the content, and can I suppose it to be reliable to write it to a new Atmega8 chip?

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Re: lock bits
Posted by: sonix ()
Date: April 14, 2014 06:22PM

Hello Alexij.

if both of the lock bits are checked (=programmed), then reading / programming flash and eeprom of the device is not possible, changing the fuse bits is also not possible.

Here is quotation from Atmega8 datasheet for lock bit mode 2:
"Further programming and verification of the Flash and EEPROM is disabled in parallel and Serial Programming mode. The Fuse Bits are locked in both Serial and Parallel Programming modes.The Lock Bits are not reset until the Program memory has been completely erased."

The content of flash and eeprom files that you have downloaded from device will be probably filled with 0xFF bytes. You should verify it with PonyProg or some other hex viewer.

So I see no chance to get whole flash and eeprom content to further data replication, if the lock bits are programmed as you described.




To be able reprogram the device you must perform Erase command (menu Command>Erase) => all data in flash, eeprom and lock bits would be erased. Then is the device ready for new programming.

Best Regards

sonix




Alexij Wrote:
-------------------------------------------------------
> Hi!
> thanks a lot for PonyProg! Very intuitive
> interface.
> As I'm a novice with AVR I need an advice smiling smiley
> I need to make a copy of the Atmega8 chip to
> restore an old unsupported device (I have one more
> "alive"winking smiley.
> With PonyProg I've managed to download FLASH &
> EEPROM content, but when I've checked the state of
> the fuses I was amused: Lock1 and Lock2 fuses were
>
> "up" (marked with v). So, how could I read the
> content, and can I suppose it to be reliable to
> write it to a new Atmega8 chip?



Edited 1 time(s). Last edit at 04/14/2014 06:41PM by sonix.

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