Communication between Teensy2.0++ and Arduino Uno

[Nicolasto]

Hello everybody!

I was wondering if it was possibile to connect a teensy 2.0++ to an arduino with a serial comunication by using the usb(on the teensy) and a FTDI breakout board.

Thank you

[PaulStoffregen]

The best way would be directly connecting Arduino Uno's RX & TX pins (pin 0 and 1) to Teensy++ 2.0's RX & TX (pin 2 & 3).

In other words, connect Uno pin 0 to Teensy++ pin 3. Connect Uno pin 1 to Teensy++ pin 2. Of course, also connect their grounds together.

On Uno, use Serial, and on Teensy++, use Serial1.

For the sake of development, you might want to connect the 2 signal wires through a double-pole switch (or 2 single-pole switches), so you can disconnect the Teensy++ when you upload new code to the Uno board.

On Teensy++, the USB is completely separate from pins 2 and 3, so you can upload new code to Teensy++ even when Uno is still connected.

[Nicolasto]

Thank you very much for the fast and complete answear. I was hoping to use all
the pins on the board and use teensy's usb for communication. Is it possible to connect teensy to a board like this http://www.play-zone.ch/de/arduino-u...t-adapter.html and get it to communicate with arduino?

[PaulStoffregen]

No, that's will not work. At least not yet. USB host most is not supported yet.

[Nicolasto]

You mean that it is not possible to convert the teensy's usb back to ftdi serial?

[PaulStoffregen]

Here's the USB spec. It's a huge document, but chapter 4 is short and explains the key details of USB, like host vs device roles.

http://www.pjrc.com/teensy/beta/usb20.pdf

Please read chapter 4. Teensy currently only supports device mode. That FTDI chip is also only a device. Chapter 4 should make the reason why this can't work much clearer.

[Constantin]

In order to make things really easy communicating between the two MCU's I highly recommend Easy Transfer from Bill Porter.