From Steak Wiki
Jump to navigationJump to search

Guide for AVRDragon, atmega328p, and optiboot bootloader.


  • wrong atmega328 (need atmega328p-pu, not atmega328-pu) (though this can still be used)
  • need fuse bits set separate from programming hex (pickit w/pics on the other hand handle this all in one)
  • need lock bits set
  • need 16MHz crystal when programming hex and lock bits (can use one from uno board)
  • avrdragon needs disconnect / reconnect

quick guide:

set proper wiring on avr dragon (see image on right)

jumpers for breakouts on avr dragon. borrowed from elsewhere.

set fuse bits

avrdude -b 19200 -c dragon_isp -p m328p -v -e -U efuse:w:0xFD:m -U hfuse:w:0xDE:m -U lfuse:w:0xFF:m

add crystal (pins 9 and 10 on atmega328p, see datasheet) , load hex, and program lock fuse

avrdude -b 19200 -c dragon_isp -p m328p -v -e -U flash:w:hexfilename.hex -U lock:w:0x0F:m

hexfilename.hex - the optiboot loader is included in e.g. arduino-1.8.5/hardware/arduino/avr/bootloaders/optiboot_atmega328.hex

If everything is done correctly, you should now be able to upload from Arduino IDE.


  • use another Uno's crystal if you don't have one on hand. Solder wires and jump to dragon ziff socket.
  • efuse verifies as 0xFD, though some guides write 0x05. High bits are unused, so they are set to 1. Ends up as 0xFD if written with either 0xFD or 0x05.
  • atmega328 (not atmega328p), use -F with avrdragon.
  • board.txt somewhere in arduino folder also has proper fuse settings (search for uno)
  • first breakout on dragon is gnd/vcc header. Obviously, multiple of these can be used.
  • if it errors out, disconnect / reconnect dragon. e.g.
avrdude: usbdev_open(): Found AVRDRAGON, serno: 00#########
avrdude: jtagmkII_getsync(): sign-on command: status -1