XMEGA A1U - Is it possible to create a PCB with an embedded debug USB?

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On the A1U eval board, there is a target USB and a debug USB. I was wondering if it was possible to keep this feature (the debug USB) when moving over to a pcb. I've read a bit into it, and it looks like it's just a few pins mapped to a USB port, but I am probably way off.

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PenguinWasHere wrote:
the A1U eval board

You mean the XMEGA A1U Xplained Pro Evaluation Kit

Part Number: ATXMEGAA1U-XPRO

http://www.microchip.com/DevelopmentTools/ProductDetails.aspx?PartNO=atxmegaa1u-xpro

I was wondering if it was possible to keep this feature (the debug USB) when moving over to a pcb

I don't think you can buy the EDBG chip anyhow, but why would you want to do this?

 

it looks like it's just a few pins mapped to a USB port, but I am probably way off

No:  it is a second microcontroller - effectively, an Atmel-ICE built onto the PCB.

 

See section 3.1. Embedded Debugger in the User Guide: http://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-42211-XMEGA-A1U-Xplained-Pro_User-Guide.pdf

 

Again, why would you want to include that in a final product??

 

 

EDIT

 

typo

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USB debug can be very useful on production hardware. Techs in the field can get diagnostic data out, load diagnostic firmware etc. No need for a bootloader, firmware update can't really fail as you can always retry with a built in programmer.

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awneil wrote:
I don't think you can buy the EDBG chip anyhow,
I've never seen that. If it were offered presumably people would be under-cutting Atmel-ICE sales right left and centre?

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mojo-chan wrote:
USB debug can be very useful on production hardware.

But I still don't see the point of putting, effectively, a full AtmelICE into the shipping product.

 

The usual approach would be to provide the debug header, so the "Techs in the field" can apply their AtmelICE ...

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clawson wrote:
people would be under-cutting Atmel-ICE sales right left and centre?

I wonder why nobody does that - especially considering the cheap ST-Link knock-offs you can buy on ebay, et al ...

(and a genuine ST-Link is only about twenty quid anyhow).

 

Did Atmel really manage to secure their EDBG so much better than ST ?

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I thought that the EDBG chip was just an ordinary Atmel MCU, maybe a AT32UC3A4256.

 

If that is the case then cloning it shouldn't be difficult.

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PenguinWasHere wrote:
I was wondering if it was possible to keep this feature (the debug USB) when moving over to a pcb.
That's a feature of the MattairTech XMEGA128A1U board :

MattairTech LLC

MattairTech

Development Boards

MT-X1S ATxmega128a1u USB development board

https://www.mattairtech.com/index.php/development-boards/mt-x1s-atxmega128a1-u-usb-development-board.html

...

Revision B now available!
...
USB can now connect directly to the XMEGA USB pins.

...

The XMEGA can be programmed over USB using the optional onboard AVRISP mkII compatible PDI programmer. 

...

Debug over PDI is proprietary though can be decoded:

https://sigrok.org/wiki/Protocol_decoder:Avr_pdi

Program over PDI is in the datasheet.

 

Edit: sigrok

 

"Dare to be naïve." - Buckminster Fuller

Last Edited: Wed. Feb 14, 2018 - 02:51 PM
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mojo-chan wrote:
If that is the case then cloning it shouldn't be difficult.
Except that the code inside it is presumably "secure" (or at least as secure as the lockbits though I think there are some models of AVr32 that have a "vault" which is presumably something quite a lot more secure).

 

The reason there are no clones is that Atmel don't document their debug protocols though a lot of it has been reverse engineered.

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mojo-chan wrote:
I thought that the EDBG chip was just an ordinary Atmel MCU

Yes, it is - just like the ST-Link is just an ordinary STM32

 

If that is the case then cloning it shouldn't be difficult.

Yes - that was my point in #6

 

 

clawson wrote:
The reason there are no clones is that Atmel don't document their debug protocols 

But neither do ST - do they?

 

 

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  2. "Garbage" characters on a serial terminal are (almost?) invariably due to wrong baud rate - see: https://learn.sparkfun.com/tutorials/serial-communication
  3. Wrong baud rate is usually due to not running at the speed you thought; check by blinking a LED to see if you get the speed you expected
  4. Difference between a crystal, and a crystal oscillatorhttps://www.avrfreaks.net/comment...
  5. When your question is resolved, mark the solution: https://www.avrfreaks.net/comment...
  6. Beginner's "Getting Started" tips: https://www.avrfreaks.net/comment...
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awneil wrote:
But neither do ST - do they?
No idea - the last time I used an ST micro it was an FM-RDS decoding dedicated one based on STM-7 this was about '97..'99

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clawson wrote:

Except that the code inside it is presumably "secure" (or at least as secure as the lockbits though I think there are some models of AVr32 that have a "vault" which is presumably something quite a lot more secure).

 

 

I don't think that will stop anyone... Last time I looked they were doing simple things like placing a metal plate over the lock bits to prevent erasure with UV, which is easily circumvented by holding the UV light at an angle so it bounces under it.