avr_fred:
Connections to what are one of many questions. Which Arduino model are you using as the programmer? Did you successfully compile and flash the “Arduino as ISP” sketch to that board being used as the programmer?You do not need to change fuse settings in order to flash a bootloader. The Arduino IDE takes care of that for you when using the “flash bootloader” function.
Please attach a schematic of your 2560 target board. If you cannot attach it to a post, PM it to me and I’ll get it into the thread. A photo of your programmer to target board connections would be helpful as well.
Thank you for your interest i really appreciate it, and i apologize for being unclear, this is my first time trying to make a standalone board and i feel a little overwhelmed. I am using an elegoo mega2560 as the programmer, and the ArduinoISP sketch uploads to it fine. I am using the ICSP breakout to the right of the chip and have the MOSI, MISO, and SCK pins attached to the respective pins on the target chip. The target board will have an microSD card reader attached, so to save space i am using the SPI pins on the target board to attempt to burn the bootloader. This tutorial http://soc.ninja/documentation/programming-atmega2560-with-arduino-uno-or-mega/ says to connect pin 53 on the programmer to the reset pin on the target chip, while the ArduinoISP sketch says to use pin 10, both of which i have tried and get the same result. Now the device signature is being read as 0x000000. I am supplying an external 5V and GND to the target chip using a usb adapter. I attached the target board schematic, pictures of the connections between the programmer and target chip, and a picture of the target chip. The empty pads by the edge had a diode and cap on them, but i tried to simplify the circuit for now down to just the 10k pullup resistor to keep components at a bare minimum. I used a multimeter to verify the conductivity of the connections between the programmer and target chip and to make sure all the vcc pins were getting 5V. The info on programming standalone atmega2560s is kind of sparse, so i could just be plugging my wires into the wrong places,. Any thoughts? Let me know if you need more info.
