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MCUdude / MiniCore

Arduino hardware package for ATmega8, ATmega48, ATmega88, ATmega168, ATmega328 and ATmega328PB
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sir,i saw a problem with hfuse for atmega328p with bootloader running on internal(8MHz) and also for external(16MHz) oscillator #307

Closed myhobby-projects closed 4 months ago

myhobby-projects commented 4 months ago

sir,i used your (version 3.0.2) minicore board manager,thanks for sharing it in github

but the minicore hfuse setting for burning bootloader (with internal(8MHz) or external(16MHz) oscillator ) has some problem

below command is for burning bootloader for internal 8MHz oscillator for atmega328p avrdude -CC:\Users\mycomputer\AppData\Local\Arduino15\packages\MiniCore\hardware\avr\3.0.2/avrdude.conf -v -patmega328p -cstk500v1 -PCOM8 -b19200 -e -Ulock:w:0xff:m -Uefuse:w:0b11111101:m -Uhfuse:w:0xd7:m -Ulfuse:w:0xe2:m

below command is for burning bootloader for external 16MHz oscillator for atmega328p avrdude -CC:\Users\mycomputer\AppData\Local\Arduino15\packages\MiniCore\hardware\avr\3.0.2/avrdude.conf -v -patmega328p -cstk500v1 -PCOM8 -b19200 -e -Ulock:w:0xff:m -Uefuse:w:0b11111101:m -Uhfuse:w:0xd7:m -Ulfuse:w:0b11110111:m

sir,why hfuse setting is -Uhfuse:w:0xd7:m for burning bootloader..

i cross checked the above hfuse many times.so please correct if i am mistaken...thank you sir

MCUdude commented 4 months ago

But what is the problem? The bootloader works just fine with these fuse settings. It's not a mistake. It is called a vector bootloader. Read more here: https://github.com/stefanrueger/urboot

myhobby-projects commented 4 months ago

sir, when minicore -Uhfuse is 0xd7:m , the Bit-0 : BOOTRST will be "1".

so the minicore bootloader will be ignored as per the hfuse settings..i cant understand why BOOTRST is kept "1"

i checked hfuse :0xDE settings for 16mhz optiboot botloader, the BOOTRST is 0 for the optiboot bootloader

MCUdude commented 4 months ago

A vector bootloader does not use the bootloader section. The reset vector gets patched by Avrdude when uploading the user program. Read the Urboot README, and you'll see why.