Stacking the Arduino Uno on the Arduino Due

Hello all, I'm planning on stacking an Uno Board below a Due Board for a radar project I'm working on, I'm wondering what adjustments to the Uno board I'll have to make for this to go smoothly.

The plan is to have an uno below a due, and a shield on the Due with all the necessary radar components. I want to use the Uno to create a triangle waveform, and the Due to do all the signal processing.

I'm going to change some of the pins on the Due so that the Uno can connect below it, and I know I should keep the 5V disconnected, is there anything else to consider though?

Are you stacking them in order to have all the pins electrically connected together, or just for packaging purposes?It seems a bit strange to connect all the pins together. Doesn't that restrict your I/O capabilities rather severely? If so, do you actually need both boards?

You can’t stack them as there are no male pins on the bottom of the cards. I’d also worry about the power pins, and you would make a real mess with the usage of pins 0 and 1.


Thanks for the responses! :)

@PeterH: The reason I want to use two boards is because I need a triangle wave (generated by an external DAC) to be constantly created by the Uno and I need the Due to constantly be processing. Originally I only had the Atmega chip directly on the shield, but since the shield is going to be expensive to fabricate and already crowded, I've decided to stack the Arduino boards instead.

@holmes4 I'm going to de-solder the pins on the due and re-solder male-female pins to make it stack-able.

Actually, since I have two Dues I'm considering using a Due-Due stack (for a faster DAC usage than the Uno can give), I've worked out which pins I need from each board and there are enough unique pins so that I won't need to have both Due's working with the same pin.

For mechanical stability, I want to have as many pins connected as possible, and I'm considering connecting Vin-Vin so I only need to connect a 9V battery to one of them. Though what pins should I keep isolated? Off the top of my head I know 5V, 3.3V, and the reference pins shouldn't interact.

but since the shield is going to be expensive to fabricate and already crowded

So you have an entire Arduino Uno/Due just to generate a triangle wave? That has to be a huge overkill. You can't fit a waveform chip or even an opamp? Give me the PCB layout, I'll make it fit :)

Remember the Due's DAC does not do rail to rail as well.