Could someone clarify bootloaders for me?

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Myrmidon
 
Posts: 27
Joined: Tue Jul 22, 2008 11:50 am

Could someone clarify bootloaders for me?

Post by Myrmidon »

Greetings all.

I was wondering, i have an arduino and i have an avrisp mk2. Now concerning bootloaders, if i was to buy a few atmega 168 chips, am i right in thinking that if i connect my avr isp mk2 to the arduino board and use the arduino ide then i can use the 'burn bootloader' option and viola, a few stand alone arduino's? (well, atmega 168's with arduino stuff)


I'm just checking before i purchase some.

:mrgreen:

edit: also i notice in the ide, can it be done for atmega8 chips as well?

mtbf0
 
Posts: 1645
Joined: Sat Nov 10, 2007 12:59 am

Re: Could someone clarify bootloaders for me?

Post by mtbf0 »

not quite.

you'll need a clock source for the mega168. either a 16MHz resonator, or a 16MHz crystal and a couple of caps. also a way to reset the chip. that'll be a button switching ground to reset with a pullup on reset or a 0.1uf cap between dtr on your programming cable and reset.

Myrmidon
 
Posts: 27
Joined: Tue Jul 22, 2008 11:50 am

Re: Could someone clarify bootloaders for me?

Post by Myrmidon »

Wouldn't the clock source on the arduino board do it? I thought it could all be done from arduino ide and board with an avr isp mk2.

Hmm, need to dig around my junk box for a resonator.

mtbf0
 
Posts: 1645
Joined: Sat Nov 10, 2007 12:59 am

Re: Could someone clarify bootloaders for me?

Post by mtbf0 »

Myrmidon wrote:Wouldn't the clock source on the arduino board do it? I thought it could all be done from arduino ide and board with an avr isp mk2.

Hmm, need to dig around my junk box for a resonator.
if you just want to use the chip in the arduino board, sure, but it you want to just program the bootloader, then pop the chip out and use it somewhere else, it's going to need a clock.

otherwise you could run the chip at half speed. this would require you to burn the lilypad bootloader and change the fuses to use the on chip oscillator which will give you 8MHz instead of 16MHz. i do this a lot, actually. the avrdude command for this is

Code: Select all

avrdude -c usbtiny -p m168 -U lfuse:w:0xf2:m
except you'll want to specify your programmer instead of the usbtiny.

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