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[on:]

Hey!

Well after buying the Arduino Due, I fell in love with it... So much that I decided to buy 8 ATSAM3X8E IC's (8 because it sums up to free shipping from the US to Sweden). Anyway before going through the process of etching and such I decided to solder the IC on a protoboard and hook it up to a breadboard for testing (before designing the final board). I don't want the programming port, so it'll be more than good to just use the native port.

Now enough history and to the problem =P. After hooking it up on the breadboard and plugging it in the USB port, nothing happens. No "pling plong, Windows" no nothing. It gets power and all, and the VDDCore is giving 1.8V as expected. But It's like I just connected some kind of charger to the PC, it gets power but no data exchange. D- and D+ on the USB are pulled low, which according to the datasheet means that the USB is disconnected (if I interpreted it right). I found a page in the datasheet that describes how the bootloader on the chip works, quote:

The SAM-BA Boot program seeks to detect a source clock either from the embedded main oscillator with external crystal (main oscillator enabled) or from a 12 MHz signal applied to the XIN
pin (Main oscillator in bypass mode).
If a clock is found from the two possible sources above, the boot program checks to verify that
the frequency is 12 MHz (taking into account the frequency range of the 32 kHz RC oscillator). If
the frequency is 12 MHz, USB activation is allowed, else (no clock or frequency other than
12MHz), the internal 12 MHz RC oscillator is used as main clock and USB clock is not allowed
due to frequency drift of the 12 MHz RC oscillator.

So if there is something wrong with the crystal then the bootloader will switch to the internal 12Mhz oscillator (which isn't as precise as the external) so the USB will be disconnected and the UART enabled instead. Which I believe means that the chip will only be programmed with the "programming port".

I've tried several 12MHz crystals, all with the same results. Maybe it's something else, maybe something I missed.

I've attached a schematic for how I hooked things up. Am I missing something important??? (Don't mind the lack of decoupling caps, I've included them on the breadboard).

Just for the record I've tried the same setup with two different ATSAM3X8E IC's.

Appreciate all the help I get!

Thanks!!

[Reply #1 on:]

I did a design with the SAM3U a while back, and although I never built it I had the same as you for the parts you are showing.

Not much help I know but at least somebody else interpreted the data sheet the same so it's likely your circuit is right (or we're both wrong).

______
Rob

[Reply #2 on:]

I did a design with the SAM3U a while back, and although I never built it I had the same as you for the parts you are showing.

Not much help I know but at least somebody else interpreted the data sheet the same so it's likely your circuit is right (or we're both wrong).

______
Rob

Hey... Yes, I did read your post while searching the forum =P.. This isn't precisely my schematic.. It's the arduino due schematic without a bunch of components =P.. I basically wanted to make a barebones arduino due...

How far did you come in your process, what kinda of problems/solutions did you stumble upon/find?

[Reply #3 on:]

Little update on the problem.. I hooked up my FTDI Breakout board (3.3V), and tried to upload the blink sketch with arduino ide, no luck (I did the erase reset manually).. I also tried to communicate with the chip using SAM-BA, also with no luck...

[Reply #4 on:]

How far did you come in your process, what kinda of problems/solutions did you stumble upon/find?

I just did the design and laid out a PCB, nothing was tested though so for all I know I would have had the same problems as you are.

I can post the schematics it you think that will help, I think I did the same as you but you may spot something.

______
Rob

[Reply #5 on:]

I can post the schematics it you think that will help, I think I did the same as you but you may spot something.

______
Rob

Yes, please :p.. didn't find a lot of those online for the Sam uC, nothing barebone atleast..

Edit: I'm designing a board that will attach to the SAM3X8E breakout. I will post a schematic and board files when I'm finished and I would be more than happy if the design experts here give me a lot of criticism =P.

[Reply #6 on:]

I got the same problem here . Using the same "minimal" Circuit.

[Reply #7 on:]

I got the same problem here . Using the same "minimal" Circuit.

Do you have everything connected exactly as the schematic that I posted above? It'll be nice if you share what you did and maybe a schematic..

I think the problem is noise related. Noise == problems with the bootloader (according to the datasheet). And I believe the breadboard environment is a very noisy one. That's why I'm moving this to a PCB instead. I'll still try to keep it at minimum (component-wise).. I'm half-way in the design.. I'll probably have something on friday/saturday...

For all that still want to go the breadboard way, try checking your connections with this check list from atmel. http://www.atmel.com/Images/doc6260.pdf

It's not specifically for the SAM3X8E, but still the same (minimum) passive components for both SAM3X8E and SAM7X**..

Edit: You kind of miss the AVR uC's.. They have worked for me even in the harshest environments!
Edit2: Here is a youtube clip of a guy who I believe etched his own PCB for the SAM7S64. I believe it's an Atmel EK (clone)..and as you see, he isn't cheap on capacitors =P..
 ,

[Reply #8 on:]

Yeah, I saw that document after I built my circuit
Ill try to create my circuit like the "3.3V and 1.8V Dual Power Supply Schematic Example" tomorrow and see how it goes. Im planning to replace the old Atmega Chips with this one but, as you already mentioned, the Chip is very critical and stubborn

[Reply #9 on:]

Here's page 1 of my schematic

http://www.robgray.com/temp/SAM3U-schem.pdf

Probably a lot of stuff you aren't interested in and the pin numbers will be different because its the 3U but the pin names are the same.

______
Rob

[Reply #10 on:]

Here's page 1 of my schematic

http://www.robgray.com/temp/SAM3U-schem.pdf

Probably a lot of stuff you aren't interested in and the pin numbers will be different because its the 3U but the pin names are the same.

______
Rob

Thanks for sharing.. Ya, it's the 99% equivalent with how I connected eveything.. Oh, well... I'll post my board soon.. And for the trouble of the etching process I hope it works.. I'll update this thread when I'm done...

[Reply #11 on:]

Yeah, I saw that document after I built my circuit
Ill try to create my circuit like the "3.3V and 1.8V Dual Power Supply Schematic Example" tomorrow and see how it goes. Im planning to replace the old Atmega Chips with this one but, as you already mentioned, the Chip is very critical and stubborn

I doubt that it'll work on a breadboard, but I hope it does.. Keep us posted!

[Reply #12 on:]

AND DON"T FORGET the by-passes... much better to have empty places than 'Hangies"... and it took me a lot of "Hangies" before I learned and a lot of 'Magic Blue Smoke" Too. I sincerely wish it didn't smell so bad, though.

Bob

[Reply #13 on:]

AND DON"T FORGET the by-passes... much better to have empty places than 'Hangies"... and it took me a lot of "Hangies" before I learned and a lot of 'Magic Blue Smoke" Too. I sincerely wish it didn't smell so bad, though.

Bob

Well, I promise to not be cheap on the by-pass caps =P.. What do you mean by empty places and hangies (sorry I'm a chemical engineer, I don't always get the electrical slang language =P).. Well I got the "magical BLACK smoke" one time when I designed a Leonardo clone under one hour =P (Pressing the reset button shorted the circuit, this happened because I misplaced the 10K pull-up resistor)...

[Reply #14 on:]

I'm the type that hate waiting, so I made a rather fast design just to get the discussion going..

Here are the files:

schematic: https://dl.dropbox.com/u/74389175/BaselM3Proto/schematic.png
Board: https://dl.dropbox.com/u/74389175/BaselM3Proto/board.png
144TQFP Breakout with Sam3x8e (TOP): https://dl.dropbox.com/u/74389175/BaselM3Proto/IMAG0453.jpg
144TQFP Breakout with Sam3x8e (BOTTOM): https://dl.dropbox.com/u/74389175/BaselM3Proto/IMAG0454.jpg
Definitions for pins on breakout and Sam3x8e: https://dl.dropbox.com/u/74389175/BaselM3Proto/SAM3X8E%20pinout.pdf

So something I thought about is the crystals. I know that it's important that the crystals are (physically)near the uC.. But how about the actual electrical connection to the uC???? Because if you look at the 12MHz crystal on the board, it's placed so that the electrical connection is as optimal as possible, but that doesn't mean that it's (physically) near the uC..

The breakout will be mounted on top of this board.. Will this work, or will this introduce another type (frequency) of noise to the board?