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Topic: Arduino Pro Mini 328 - 3.3V/8MHz modded (Read 1 time) previous topic - next topic



As topic says.Well no wiser as what bootloader i should use?
Worried that my crystal is not right, using 8mhz with 25pf caps. Don't have datasheet for it.
I swapped resonator for crystal thats the mod otherwise the same.

I've been looking at makefiles that come with ide and downloaded optiboot makefiles.
I don't see clear option for fuses and other options. So totally confused....

I've isp something on there to check rx/tx and all works apart from i can't upload using my uno.

HELP please :)



I'm not quite sure I understood your question.  Do you want to update the factory installed bootloader to Optiboot?  If so, the easiest way is to use another Arduino board running Westfw's "Optifix" sketch.  However, you'll first need to update the hex data in Optifix for the 8MHz crystal, and to do this you need to recompile Optiboot.  Or if you like, I can (later) dig out the version I already compiled and send you the lines which need changing.



Well i got the 8mhz 3v3 328p working. I used arduino IDE bootloader with usbtiny.
I did however download arduino files from GIT and unpack Hex files from that.

I was getting very worried i'd screwup flashing bootloader. I'd tried to get atmega88 3v3 8mhz optiboot with no luck, 16mhz works great.

Well got it working with at90usb162 usb/serial using re-complied arduino serial/dfu.
When i said modded, i meant diy pcb. I'm proud of it but wouldn't pay for one LOL!!!
Well i will have to do something now got it working :) Happy days..

Would be interested in 'optifix' details,thanks


Ps i do have proper button but that was nearest at that moment :)


Get Westfw's Optifix sketch from here: http://arduino.cc/forum/index.php?topic=28733.0
Load the sketch file into an editor and scroll down to the hex data at the end.  This is the Optiboot binary.  To adapt the code to run properly on an 8MHz board, alter just the 3rd and 4th lines of the hex data as follows:
Code: [Select]

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