Tag Archive for jtag

[Arduino] Burn JTAG Enabled Bootloader on Arduino Mega (ATmega2560)

To enable the JTAG Interface on an Arduino Mega the JTAGEN fuse bit must be set to zero.

A modified Arduino bootloader with JTAGEN fuse bit enabled can be programmed by using an Arduino Uno as ISP (In-circuit Serial Programmer).

The Arduino IDE can be used to burn the bootloader after making the following modifications to <Arduino IDE Path>\hardware\arduino\avr\boards.txt

"C:\Program Files (x86)\Arduino\hardware\arduino\avr\boards.txt"

The following calculator can be useful to calculate the correct value: Fusecalc

The mega.menu.cpu.atmega2560.bootloader.high_fuses value is modified from 0xD8 to 0x98

## Arduino Mega w/ ATmega2560
## -------------------------
mega.menu.cpu.atmega2560=ATmega2560 (Mega 2560)


# mega.menu.cpu.atmega2560.bootloader.high_fuses=0xD8

Connect the Arduino ISP (Arduino Uno) to the target (Arduino Mega).
Connect the Arduino ISP (Arduino Uno) to the PC with an USB cable.


Arduino Uno as ISP <-> Arduino Mega 2560

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