Lockbit configuration

Hi Guys!

I want to protect my Arduino from cloning.
The most i can do against it, that is set the correct Fuses/Lock bit trough AVRDUDE on SPI port.
I got USBASP, Extreme Burner AVR, so i can set the Fuses/Lock bit's.

I uses this calculator:

https://eleccelerator.com/fusecalc/fusecalc.php?chip=atmega2560&LOW=62&HIGH=D9&EXTENDED=FF&LOCKBIT=C0

But i am totally confused in settings.
What i need to set? I want to prevent code downloading into hex file. If i disable it, can i upload a new code trough bootloader? Or i need to disable Bootloader to for fully safety?

Névtelen

Do i need to uncheck the "Serial program downloading (SPI) enabled; [SPIEN=0] *" line?
What sould i chose from the buttom menu? Disable LPM, SPM?

What's the different from this menu? Wich one i need to configure?

Névtelen

If you can write me the correct fuses/lock bit values for my needs, then i will be pleased!

Thank you for yours answers

There is no way to protect your code without getting rid of the bootloader.

Thank you! What do you think, these settings are okey?:

https://eleccelerator.com/fusecalc/fusecalc.php?chip=atmega2560&LOW=62&HIGH=F9&EXTENDED=FF&LOCKBIT=00

So i disabled "Serial program downloading (SPI) enabled; [SPIEN=0] *" and set all Lock Bit settings to disabled

I have Read a lot. Now i understood some thing, but i have some question.

So the methode is: We write a program in Arduino IDE. Then compiled program saved in .hex file on the local PC. I load this hex file with Extreme Burner AVR program, and i set the lock bit to 0x00, then burn the program.

  • In this case after we upload the program, the lock bit are set, so i cannot read eeprom and flash memory with AVRDUDE-like program. It's true?

  • When i write with ISP programmer and "Boot Reset vector Enabled (default address=$0000); [BOOTRST=0]" unchecked, then the bootloader automaticly deleted?

  • In this case i am protected from beign cloned? :smiley: