XMEGA A1U Xplained Pro - Trick to using EDBG Virtual Comm Port?

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Hello fellow freaks,

 

I have some serial port code that was previously working on a dedicated custom target board, and have now (attempted to) port it to the XMEGA A1U Xplained Pro board.  I am trying to communicate via USART E0, the one connected to the CDC UART pins.  The EDBG documentation says there is a virtual comm port, which I can see in Tera Term.  I can't seem to get anything to happen, though, communication-wise.  Is there some trick to using the virtual comm port that I am missing?  Thanks in advance!

 

Altazi

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I have some serial port code

Was this for AVRs? Xmegas are a bit different. Maybe you could post your code.

 

This is what I have been using with USARTD0 (and USARTC0) just change all the D0 to E0 references.

(EDIT I think I used AS4.18 and you will need to IMPORT in AS7)

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John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

Last Edited: Sat. Jul 1, 2017 - 03:25 AM
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Hi js,

The code is for the xmega 128A1U. It works. I can step through it and see the UART data register being written. My question, and problems, are with the EDBG virtual comm port usage. What must I do to use the virtual comm port? I have a fair amount of experience with the A1U, but this is my first time with the Xplained Pro.

Altazi

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What must I do to use the virtual comm port?

Nothing that I know of, if the port appears on the Device manager when you plug the board in it should just work.

 

From memory there are 2 resistors that can be removed if you want to use those 2 bits for something else otherwise the chip should be programmed as a USART bridge.

 

I'll see if I have any docs on that board, my board is the old Xmega128A1 non U version.

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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Thanks, I appreciate it.  There is probably something simple that I am missing . . .

 

Altazi

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The old board had a jumper that selected either the programmer or the CDC USART. I don't think this is the case with newer Xplained boards with the debugger built in.

 

With the new Tiny817 Xplained board the USART appears as a virtual port even while debugging.

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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Does your terminal program set the DTR signal? That is required for the debugger to enable its UART pins. From the Xplained Pro user guide:

 

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Thank you all.  I jiggered with the settings in Tera Term and got it working.  That DTR thing, I guess . . .