AVR JTAG ICE v2 = 5V; ATXMEGA128A1 = 3.3V; Will it fry or is it safe?

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I bought AVR JTAG ICE version 2 programmator. I already have an ATXMEGA128A1 on my dev board. Now, as the board is expensive and from school, I wouldn't like to fry it. The programmator works at 5V while my microcontroller at 3.3V. My mentor says that connecting these two will cause friage if not on the same voltage level.

Other than that, in a documentation about some general JTAG AVR programmator, it said that the programmator will adjust its power supply according to the target. I'm not sure about that. I measured the voltage on the programmator's pins and it said 5V. On the dev board, it said 3.3V.

So do I first have to unplug the programmator's USB, plug in dev board's USB, plug programmator into dev board and then plug the programmator's USB? I feel very uncomfortable about this. I have only one attempt to do this resulting in success or friage. I'm sure you guys have been there and had programmators so surely you somehow solved the problem. If you know how, I would like you to tell me.

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"Dare to be naïve." - Buckminster Fuller

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In which order do I have to plug these devices? I don't think plugging the powered on programmator into an unpowered dev board will make the programmator recognize the voltage of the dev board if the programmator is already sending 5V. Are you sure it will?

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Atmel Logo

JTAGICE mkII
Getting started

Powering the Atmel JTAGICE mkII

http://www.atmel.com/webdoc/jtagicemkii/jtagicemkii.connecting_powering.html

...

When the JTAGICE mkII is properly connected to the target and the host PC, the power can be turned on. It's recommended to power up the JTAGICE mkII before the target is powered, to avert the possibility of current flowing from the target into the unpowered JTAGICE mkII.

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"Dare to be naïve." - Buckminster Fuller

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Works! I connected in this order:

  1. Dev board {USB} PC
  2. JTAG programmer {USB} PC
  3. JTAG programmer {10-pin connector} Dev board

 

I opened up PuTTY to see does my program work. Entered some random letters and pressed enter and it said the command doesn't exist. Which means, it works!

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Good to go.

Foxcat's JTAG is NOT an Atmel type but a cheap Chinese JTAG Mk1, so all bets are off. (See other thread)

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

Last Edited: Thu. Mar 26, 2015 - 07:47 PM