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Topic: 328 3v 8mhz boot loader (Read 592 times) previous topic - next topic

stoopkid

I wish to use the atmega328 at 3v but still with ok timing. I have some 8mhz crystals, would the arduino pro mini boot loader work fine for this or is there a better boot loader for this scenario?

Thanks

Krodal

If you use the pro mini atmega328p version (and not the atmega168) you will be fine.
The bootloader doesn't care about voltage, you just need it for the 8MHz. Building and uploading your sketch should also be done with the pro mini setting.

stoopkid

I am trying to bootload the pro mini 8Mhz board onto my 328 with a tinyusbavr but I get this error:

Quote
avrdude: verification error, first mismatch at byte 0x7980
         0x21 != 0x88
avrdude: verification error; content mismatch



I have no problems burning the regular UNO bootloader. I tried doing it on the arduino board and on a breadboard with different combos of 3/5v and 8Mhz crystal.

Any advice?

Thanks.

Krodal

I don't understand it. Perhaps some kind of timing problem.

I did a test with Arduino 1.0.3 with my Arduino Nano (ATmega328P-AU, 5V, 16MHz) and a USBasp programmer.
The bootloaders could be programmed without any error, just as I expected.
These are the bootloaders I tried:

  • Nano ATmega328

  • Pro or Pro Mini 5V 16MHz ATmega328

  • Pro or Pro Mini 3.3V 8MHz ATmega328



stoopkid

Ok I figured it out. I had two main problems. First, the tinyusbavr was supposed to be powering the arduino while it programmed but I guess it wasn't doing it right (maybe something about the other 5v pins on the chip). I switched it to no power and powered the arduino with USB and it bootloaded fine. Then to program it I had to take it out of the arduino and stick the 8Mhz crystal on a breadboard, it wouldn't program with the 16Mhz chip in the arduino.

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