I installed Atmel studio some days ago, but had no much time to test.
Which files must be (how) changed to use it with Teensy 3 ? Can you help me with that ?
Or, is there a "howto" ?
You already have Arduino 1.0x installed, I assume.
Install Atmel Studio 6.1. I've not used beta 6.2
Install Visual Micro. It's free. The debugger is an optional shareware. You can procrastinate that.
Take all the defaults for these.
For more automation of switching board types from AVR to Teensy:
In the installation directory for Arduino 1.0x and in the teensy directory for teensy, edit the boards.txt file with an editor that copes with no CR's like Programmer's Notepad.
The path may be: C:\Arduino\hardware\teensy\boards.txt
Add these to the Teensy 3.1 section
teensy31.build.option5=-DF_CPU=96000000
teensy31.build.option6=-DUSB_SERIAL
teensy31.build.option7=-DLAYOUT_US_ENGLISH
Add these to the Teensy 3.0 section
teensy3.build.option5=-DF_CPU=96000000
teensy3.build.option6=-DUSB_SERIAL
teensy3.build.option7=-DLAYOUT_US_ENGLISH
save, restart
(I haven't worked with Teensy 2 with Studio and VM).
Takes some learning to use this.
Some quick notes
Visual Micro adds a new toolbar, 3rd down. You'll find Teensy boards among the choices. Same toolbar, you'll see the COM ports for Teensy and AVR. You can choose one, click the PC icon and a new window opens for that COM.
You can drag the terminal window and drop it to pane it into the other windows. You can open more serial monitor COM ports and add that window to the other, and stack them paned rather than floating. These terminal windows will
stay put despite changing board types, downloading, etc.
Use the FILE menu, and NEW and "sketch" for a new project that's Arduino/Teensyduino specific.
It'll open and use a .ino file.
It has the "solution" concept where you may have multiple projects in one work session. I don't use that.
I do use the same source code file but change the target board type, compile, download. Jump back and forth between board types. I run 4 boards at once in my wireless work.
The editor in Studio is great. Right-click to lookup functions, refactor names. Click on a function that you're calling then use the "goto" button to jump to the file and line where that's implemented. And so many more.
Productivity increased 1000% versus a dumb editor.
I've used Eclipse too, but it's not well done for the Teensy. Same, Codeblocks.
much more on the visual micro website