2560 borad draws 200mA


I made a 2560 core board, and I drive it with a 5 V power supply. I loaded a blink ino. But the chip feels hotter than a regular arduino 2560 board. And when I measure the current, it is around 200mA. I don't think there are anything much more than the bare chip.

The resonator is a regular 16MHz one, shown in some BOM of a regular 2560 R3. Is this something expected? Is there any thing I can do to improve this power efficiency like fuse setting?

You may want to include your schematic.


Can you include a larger schematic? I can barely read that one. And the grid makes it even harder.
Are you connecting 5V to X1? The diode and regulator (? can't read it) will knock the 5V down a lot.
A 2560 needs 4.5V minimum.
A 2560V can run on lower voltage.

I have uploaded the schematic and in a larger resolution. After downloading it one can see the details better. I don't have the regulator in this circuit, because I powered it using a 5V supply. It is quite strange that this consumes that much power. I think the next what I can try is to swap the chip of a regular arduino 2560 board with the chip I used on this.

Could use a couple more decoupling caps, one for each VCC and AVCC pin, but I don't see anything electrically that would make it draw more power.
Did you set the fuses the same as in a Mega board?

Your schematic does not show loading capacitors on the xtal . Normally they are required.

The schematic doesn't show any reason to draw 200ma. Although I didn't see a current for the buzzer (which is 12V) but I'll assume if the buzzer was on you would have reported that.

So this being a new board I would first touch the components and see if one were hot or warm.
I would then inspect for shorts (solder splash etc)

In the first post,@joedodo indicated a resonator was being used, vs a crystal.

Thanks, I've never used a Resonator (at least not my design) but was under the impression capacitors were required. I guess I was wrong.

Anyway I doubt it has anything to do with the excessive current draw.

Caps are built into the resonator, hence no external caps are needed.

1 Like

Thanks for the decoupling caps suffestion. I didn't explicitly set any fuses yet. Because I tested it by first loading the bootloader of a regular 2560 r3 using the ide and icsp pins and then uploading sketches using the serial port of this board with the arduino ide and manually pressed the reset button. I assume the fuses settings should be same as a regular 2560 r3 .

I found someone else experinced similar high current, on the 12V port.

I don't know the result/solution of it.


What type of buzzer are you using? Could you check its resistance? I assume you set PB0 at LOW and it wouldn't matter the resistance but just in case you set it HIGH, there could be some current through the buzzer.

This topic was automatically closed 120 days after the last reply. New replies are no longer allowed.