Standalone Mega Not Running Sketches

Hi all,

I made a standalone Mega (2560) board.

  • It uses a 16 MHz resonator.
  • Serial (RX-TX) pins are connected to a FTDI FT232RL, over 1K resistors.
  • The FTDI chip is only powered when USB is connected.
  • The FTDI DTR pin is connected to RESET through a 100nF.
  • USB Ground is connected to GND.
  • All SPI slaves are disconnected from the MISO, for now.
  • Reset is pulled-up to 5V, as should be.
  • RX pin is pulled-down to GND with 20k, just in case it gets garbage and confuses the bootloader.

And,

  • I can burn the bootloader, via Arduino ISP (A Duemilanove as ISP).
  • I can upload a blink sketch using the Arduino ISP.
  • I can’t upload a sketch using FTDI (FTDI is recognized by Windows 7).

So, the problem is, when I upload the sketch, it doesn’t run. Something stops the 2560 from starting execution.

2560 was a factory new chip. I am experimenting with different fuse options without success.

Any ideas?

For future reference, if you need to burn fuses using Arduino as ISP, you must set the HFUSE to D9, not D8. Otherwise loaded sketch will not run. Even bootloader won't run. You can change it from boards.txt (hardware\arduino\avr\boards.txt in Arduino folder) like this:

mega.menu.cpu.atmega2560.bootloader.high_fuses=0xD9

and restart Arduino IDE.

Is that working now..