atmega328 on a breadboard on arduino 1.8.5 not showing up

That was my initial assumption and I even measured the value with my multimeter running the blink sketch keeping the led lit for 10 secs and I saw 4.5+V most of the time. Yes, actually a little less than 3.3 V on the output pins, but not so much that it matters.

So, in summary: while burning the minicore, I select my frequency and then just power it up with 3.3v in the vcc pin and the HIGH values sent on the TX pin will be 3.3V as well ? The breadboard hardware package's bootloader also has a bug that causes it to go into an infinite reset loop if you use the watchdog timer.

It also provides a more modern bootloader that fits in a 0.5 kB boot section, saving 1.5 kB of precious flash memory compared with the breadboard package's outdated bootloader. The only difference is that while the 'breadboard' hardware package only permits a single board configuration, MiniCore gives you a bunch of configuration options via custom menus that appear under the Tools menu after you install MiniCore and select one of its boards. So even if you only want to set fuses in the Arduino IDE, you will use the Burn Bootloader command. The Arduino IDE's Tools > Burn Bootloader is a two step process: Is it done at some point during the install or burn process? The boot reset vector is enabled (for using the bootloader). This is the area of flash memory reserved for the bootloader. The boot section size is set for 1024 words (2 kB). The clock is set for the internal RC oscillator, 8 MHz. _bits=0x0FĪnd here's what that configuration gives you: In the case of the 'breadboard' hardware package: _fuses=0圎2Ī_fuses=0x05 The clock and BOD fuse settings are in boards.txt. For example, if the BOD is at 4.3 V and you're running at 3.3 V then the microcontroller will just constantly reset. You also might want to set an appropriate BOD level. The most important consideration for 3.3 V operation is that the ATmega328P is not rated to run at 16 MHz with 3.3 V supply voltage. If you power it at 5 V then you get 5 V I/O.

If you power the ATmega328P at 3.3 V then you get 3.3 V I/O. I/O pin levels are relative to the supply voltage (slightly less, see datasheet).

Atmega328 on a breadboard on arduino 1.8.5 not showing up