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Topic: Bootloader 3.3v 8MHz (Read 12235 times) previous topic - next topic


I tried this again last night with no luck, I decided to try and upload the sketch directly with the avrisp I changed the preferences file to upload using avrispmkii but when I tried to burn the sketh the IDE was still expecting a serial port.

Do I need to modify anything else to make that work?  still stumped as to why I can't upload sketches with ftdi, the only thing I wonder is if the 8Mhz resonator that I am using is not up to the job.

Did you shut down the Arduino software before making the change and then re-starting?  I think Arduino generally reads the preference.txt and boards.txt files only at startup and writes them (at least preferences.txt) back on shut-down.
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Hi, yes, I shutdown before.

Basically when I set the upload using avrispmkii and then hit the sketch upload button it asks me to select a serial port like when uploading via ftdi usb.  However when I burn a boot loader with the programmer it just goes ahead and does it no questions asked.


Mar 24, 2017, 06:59 pm Last Edit: Mar 24, 2017, 07:12 pm by rodrigorrm Reason: Just added a picture of the assembly for bootloader burning
Hello guys,

I'm having a hard time putting together a breadboard Arduino @ internal 8MHz clock and 3.3V power.

I used the instruction laid as in: https://www.arduino.cc/en/Tutorial/ArduinoToBreadboard.

The resulting arduino worked just fine @ 5V. I managed to burn the bootloader indicated for internal clock and also managed to upload my application.

However, it just does not run when I switch power to 3.3V.

Just in case I attached a picture of my setup for burning the MCU.

What am I doing wrong?

Thank you,



"What am I doing wrong?"
Picture didn't make it. Reply, and scroll down to Attachments and other options, browse to your file.

"it just does not run "
So what does it do? When you burned the bootloader, did you select a board type that used the internal 8 MHz oscillator?
This IDE add-in makes it easy to set different options for speed, clock, brown out detection (reset when power voltage gets too low), etc.
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