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Topic: Schematic error on Zero Digital-4 and Digital-2 (Read 953 times) previous topic - next topic


I think the V1.0 Zero schematic is wrong. Digital-4 goes to SAMD21 pin 13 (not 23), Digital-2 goes to SAMD21 pin 23 (not 13) on my board.


Mar 21, 2017, 03:06 pm Last Edit: Mar 23, 2017, 05:37 pm by scswift
A little backstory:

There are two Arduino companies, Arduino.cc and Arduino.org who were feuding over the trademark a while back (but have since made up) and one made the Arduino / Genuino Zero, and the other released the Arduino M0 PRO. The latter was released first, and for whatever reason, those two pins were flipped before the "real" Zero was released.

Now, I'm not sure which schematic you're referring to, so I looked at the Zero schematics posted here:


And I see something weird there:

You say D2 goes to P23 on your board. That would indicate you have a real Zero.

But on that schematic D2 goes to P13, which is wrong. And its NET is labeled as PA14 which is correct, but that net is connected to pin 13 / PA8, which is wrong. So the net is labeled correctly, and your board is correct, but the pin the net is connected to on the schematic is wrong, and that could lead to confusion.

Btw, my Neutrino is based on the Zero from Arduino.cc, and you can see its schematic and a pinout card here, which show where D2 is supposed to be connected and have the correct ports and net names:


So in summary, on the Zero (and Neutrino), D2 goes to P23/PA14, and D4 goes to P13/PA8. On the M0 PRO, this is reversed.

I hope that answers your question!


Thanks, that's interesting background info. This is a confusing mess. My board looks exactly like the Zero (USA version) on the Arduino store.

The Arduino IDE (1.8.1) reports the board as a Genuine Zero.

A digitalWrite(2, High) activates SAMD21 pin 23 and Digital Output 2. 

The Arduino net label is wrong and so is the Gerber. It might be better to use Adafruit or Sparkfun for document checks.


Mar 23, 2017, 09:53 am Last Edit: Mar 23, 2017, 09:54 am by MartinL
Hi dougJack,

When the Arduino Zero first came out, arduino.cc published Atmel's (correct) schematic on their products page.

Please find the schematic attached.


I'm sorry, I got the pin numbers and ports backwards when I was describing things. You have a genuine Zero.

I have corrected my post above to have the right information.

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