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Topic: Errors in Due board/schematic files (Read 23233 times) previous topic - next topic


Jun 16, 2013, 01:55 am Last Edit: Jun 16, 2013, 02:35 am by michaeluna Reason: 1
Graynomad, you're a helpful dude. Thank you so much for your expertise.

Here's my schematic. I literally just opened the Due release files and added some of my own circuitry to it to make this musical instrument I've been designing.


I have a question related to JTAG here, because that's the next avenue I'm exploring to figure out what's up with my boards.

The 10-pin connector the JTAG on the Due boards has 1mm spacing, which is super small. I'm looking high and low for the connector cable to attach to those pins and I'm not finding it anywhere. Maybe it's because I din't know what it's proper name is? In any case, do any of you have a link to the type of cable that connects to those pins?

In my next revision of the board I'm switching that header to the standard size. And making both USB jacks identical, that was a huge headache as well...


The spacing is actually 1.27mm or .05", they are reasonably common although nowhere near as much as the .1" version.


Or if you need to convert to the standard 20-pin JTAG this should work


And making both USB jacks identical

So they should both be micro AB sockets then I assume.

Rob Gray aka the GRAYnomad www.robgray.com


Jun 16, 2013, 02:48 am Last Edit: Jun 16, 2013, 02:52 am by Graynomad Reason: 1
I gather that schematic is not yet finished? There are a lot of unconnected nets.

Where do all the debounced switch inputs go?

EDIT: I also juts noticed that none of the wire joins have dots, that normally means they are not connected.

Rob Gray aka the GRAYnomad www.robgray.com



From going over the DUE schematic some time ago, I remember questioning the existence of T2.  It is a P-channel fet that always seems to be turned on.  It doesn't harm anything I suppose.  However, it would never turn off unless the 5V power port suddenly became negative.  I've seen uses like this for battery-polarity reversal protection.  I'm not sure how it applies here though.

I had some other minor comments that can be found here:

Also, when it is obvious, I think that judicious use of power-ports and net-labels make a schematic easier to read, and preferable over crossing wires (i.e. the bank of switches, digital pots, and so forth).  If you're trying to convey special pcb grouping, routing, or operation with the display of the wires on the schematic, then a few words on the schematic print would go a long way to explain your intentions.

Rob is right-on about the junction dots.

Best of luck with your project.



Aug 26, 2013, 05:06 am Last Edit: Aug 30, 2013, 05:06 pm by emech Reason: 1
I would like to confirm the post from Aiekakiku (thanks!) http://forum.arduino.cc/index.php?topic=168399.msg1279303#msg1279303
R23 is the wrong value. It should be 1K

On my DUE it was preventing the 16U2 from resetting the SAM3X and causing the "No device found on COMxx" errors.
It also prevented the SAM3X from being reset after successfully loading a sketch.
I suspect that many others have this same problem on the DUE.

my related post with details: http://forum.arduino.cc/index.php?topic=167492.msg1366523#msg1366523

Update: See also http://forum.arduino.cc/index.php?topic=167492.msg1373055#msg1373055 for the necessary 16U2 firmware fix


i think this thread should ''official'' and all the differences between reference schematic and real board should be posted here


@michaeluna... I've been doing schematic drawings for nearly 50 years and "That" is the most unique and difficult to follow schematic drawing I've seen yet.
That having been said and it wasn't intended as a criticism by any means your work, as far as it goes is OK.
Remember always that a schematic is a road map first and in many cases additional material not usually included in the BOM is represented on the schematic.
Individual circuits like the Power Supplies, Controller and I/O circuitry are usually in separate area's... The Uno drawing is an example of one that is close to the ideal.
I used a high end cad package when I last worked (2008) and I do realize that struggling with a 'difficult' free package has it's special challenges, ones you have done well with.
My best piece of advice would be to study how others (professionals) compose their drawings and try to incorporate (copy the style) of the most legible and understandable ones into your style.
A Schematic drawing is an engineering document used for many different purposes and by many different people. All the way from the poor techie that has to use it for troubleshooting to the people who actually order parts and use the schematic as a means of verifying the BOM for accuracy... of parts and sometimes the count as well.
And let's not forget the other engineers that may need to use the drawing as well... Great work for a beginner.

--> WA7EMS <--
"The solution of every problem is another problem." -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard


I have found a group label inconsistencies in the schematic.  The naming of the AD inputs is flipped in the schematic.

Sources: Atmel SAM3X datasheet 23-Mar-15
                  Arduino DUE Schematic (download fom site dated ?)

Peripheral from pg.18
Datasheet Labels from pg.40

 Pin #  Peripheral  Label (Datasheet) Label (Schematic)

78          PA16              AD7                 AD0
79          PA24             AD6                 AD1
80         PA23             AD5                 AD2
81           PA22             AD4                 AD3
82          PA6               AD3                 AD4
83          PA4               AD2                 AD5
84          PA3               AD1                  AD6
85          PA2               AD0                 AD7

If this was a Civil Engineering forum would there be posts like "I need to build a bridge. Someone send me drawings."


ADC Channel 7 is A0
ADC Channel 0 is A7

It's weird…but correct. :smiley-confuse: 

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