Programming a custom arduino due board

First off, happy thanksgiving to everyone. :slight_smile:

So here's the story. I custom built my own board for my project using the atsam3x8e. I double checked everything with the checklist provided by Atmel and going back and forth between the arduino due eagle files and a clone board called the TAIJIUINO Due.

However I made a small mistake...

Basically, when I was ordering the parts on digikey the D+ D- pins used by the USB require a 39 ohm resistor and I bought a 39K. Now im not sure if those resistors would work just as fine but I ordered an extra pair from digikey, the only issue is that I want to be able to program the board before the resistors get delivered as I am running out of time.

Please keep in mind that I am new at all of this and I am trying really hard not to make mistakes.

As I wanted to keep the board as debugable as possible I made headers for the JTAG port, a debug port, ICSP, and a programming port which essentially are the same pins used by an additional microcontroller which are connected to the first UART of the SAM3X (RX0 and TX0).

Now I am not very fond of JTAG but with the little research I did it seems I need a JTAG programmer which is a bit expensive and honestly I dont see the use of buying it as I would only use it once, plus, the time it would take to arrive is too much for me at the moment. If someone can give me a cheaper solution to use the JTAG it would be nice.

The programming port seems to me as the best option to program the custom board but I am a little clueless as to how to use it.

I currently have with me both an arduino uno and a due board at my disposal.

Is there any way to program my custom board with the UART port I left open? I have all the ICs required to convert the 5V signal going into those pins into a 3.3V so that is taken care of.

I know I could wait until the resistors are delivered but would love to be able to program the board before that date.

Thanks to all in advance.

the TAIJIUINO Due board has a little attachment board with the same Atmel chip here it is:

Is there a way to emulate this with the arduino boards and somehow connect it using those pins?


Native programming should work. The only time it won't work is if your sketch currently on the Due has locked up in a way that prevents it from seeing the USB data. That's why there's an "erase" button on the original Due.

Unlike the AVR chips there's no bootloader programming required. The chips ship with an equivalent of a bootloader stored in ROM that cannot be replaced or damaged.