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pietern

Member Since: February 8, 2014

Country: United States

  • While the description says the board comes with a 8MHz external resonator, the processor isn't configured to actually use it (I measured it running at approximately 7.85MHz). The AVR pocket programmer isn't suited to flash this processor, but it can be used to read and write the fuse bytes.

    The fuse bytes were set to L:0xE2, H:0xD4, E:0xFD, which means the processor is configured to use its internal oscillator. I set the low byte to 0xD6 (this sets the clock source to "Full Swing Oscillator; Start-up time: 258 CK + 65 ms; Ceramic res.; slowly rising power") and measured it running at 8MHz dead on.

    I used the AVR pocket programmer for sale here on SparkFun. I soldered an ISP header onto the Mega Pro Mini board and connected the pocket programmer (pin 1 is marked on the Mega Pro Mini board, power the board with a separate power source). Then I used avrdude to read and write the fuse bytes. Write them with the following command:

    avrdude -V -D -p m2560 -c usbtiny -U lfuse:w:0xd6:m -U hfuse:w:0xd4:m -U efuse:w:0xfd:m
    

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