can i run Atmega1284P at 3.3V and 8Mhz speed.? can i burn Nick Gammon Arduino bootloaders into the chip.?

Thank You

1 Answer 1


Atmega1284P 8MHz @ 3.3V?

Yes, you can. Documentation states this is permitted voltage for that frequency: 0 - 10MHz @ 2.7V - 5.5V http://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-42719-ATmega1284P_Datasheet.pdf

Nick Gammon Arduino bootloaders?

On this page http://www.gammon.com.au/bootloader it states Atmega1284. In code https://github.com/nickgammon/arduino_sketches/blob/master/Atmega_Self_Read_Signature/Atmega_Self_Read_Signature.ino there is signature for Atmega1284P so it should work without issues.

  • Thank you for replying, Nick Gammon supports Atmega1284 with 3.3V and 8Mhz.? I am confused - web page states only with 5V and 16Mhz not with 3.3V and 8Mhz. :/ Oct 12, 2017 at 17:06
  • You may be right, I understood you asked only for burning bootloader in chip. If that is the case, than you either need to modify code (so to enable correct working on that frequency) or ask Nick Gammon to support that combination also. Please take note that only frequency is "problematic", voltage is ok if MCU can work at that voltage and speed.
    – Darko
    Oct 12, 2017 at 17:17
  • 1
    The bootloader doesn't need to know the voltage at all - you set the fuses for the brownout detector via ISP. And it will work even with a slower clock, however in the case of a 16 MHz bootloader actually running at 8 MHz, you'll have to configure the upload baud rate in Arduino (boards.txt or whatever it is these days) to half of what it would be if running at the designed clock rate - so if it was designed to be 115200, half clocking would result in 57600. Oct 12, 2017 at 17:51

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