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Help with ATSAM3X8E

Posted: Tue Mar 05, 2013 1:31 am
by baselsw
Hey! New to this forum (coming from the AVR side of life) and really excited for joining the Dark Side (ARM).

I recently bought 8 ATSAM3X8E IC's to play with. 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).

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 UART.

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!!

Schematic: http://dl.dropbox.com/u/74389175/due_barebones.png

Re: Help with ATSAM3X8E

Posted: Wed Oct 22, 2014 5:13 am
by anhtuanhoang
Hello,
dear all,
i'm a new engineer with the sam3x8e mcu so i have a lot of questions about this but i can't find more topic about this for the beginner. i only find this one.
i'm designing a board base on arduino technology with atsam3x8e mcu, so can you help me to answer this question:
- is your schematic ok? how about the erase button because i see that with the arduino there're a circuit with this but you only have a button.
-what is uotgid use for ?
- i see think that i can use the atmel studio to write for the program and use only the usb like your project to program for this, is it right ?
thank you very much for see and answer my questions because i can't find how to working with this on the internet.

Re: Help with ATSAM3X8E

Posted: Mon Nov 17, 2014 3:11 am
by nutsnbolts
You've no mention of any firmware... (these things don't just run 'out of the box'!). If you've got problems, it's a knocking bet that's where they lie. Sorry to do this... but, if you want help, you need to (at least) outline everything you've done, including the code you've uploaded to the chip.

See my reply to discussions/viewtopic.php/f,24/t,23399.html
I'm sure similar will apply to sam3x8e. 

anhtuanhoang- see http://www.beyondlogic.org/usbnutshell/usb1.shtml
-and subsequent pages for "uotgid"- it'll be described as "USBID"

Mike.