Arduino as USB-to-serial converter

Is it possible to use the Arduino as a USB-to-serial converter, making it possible to talk to another stand-alone micro controller (eg. ATtiny2313)?

Can I just clear the Arduino (empty void setup and void loop) and then connect RX and TX on the Arduino to their corresponding pin on the micro controller?

That would probably work if the other controller has the same voltage levels for it's seral interface, and if you remember to connect the grounds also.

Sweet! Thanks!!! :slight_smile:

I started thinking about the question, and I agree with MikMo that it'd probably work, but then it made me wonder something. For some reason it's general practice to remove the ATmega328 from the socket before doing this. Why is that if this works too?

Another alternative is to use a dedicated USB-to-serial board like this one. I don’t own one, but I’m a big fan of Modern Device: I have one of their RS-232-to-TTL converters, and 5 of the RBBBs, and have found them to be a great supplier at low cost. The BUB board is cheaper than any Arduino, so it makes sense if you’ll be using it a lot.

I don't see where the hassle of USB comes into this. If you just want an Arduino to talk to another microcontroller, why not just go serial to serial??

I've done something that may be useful to you... just replace my Windows XP with the microcontroller of your choice. The challenge in the following might be a useful starting point along the road to where (I think) you want to go...

Maybe, but I would have to be convinced.

Note that even the designers of the Arduino chose to NOT do that. Note that they use a separate chip (FT232RL) to handle the USB protocol overhead and convert it to serial.

It is not clear that you even have enough memory in an Atmega chip to hold all the code necessary to implement the full USB protocol such that it would talk to a PC/Windows or Mac host machine with the default drivers. It is taken care of for you by the custom programming of the FT232RL. You would need a pretty compelling reason to not just use an FT232RL. It is easier, faster and cheaper. Doesn't get much better than that.

I think the OP was actually referring to using the FT232RL that is onboard the Arduino, rather than the ATmega chip itself.

Is it possible to use the Arduino as a USB-to-serial converter, making it possible to talk to another stand-alone micro controller (eg. ATtiny2313)?

Can I just clear the Arduino (empty void setup and void loop) and then connect RX and TX on the Arduino to their corresponding pin on the micro controller?

It should be no problem as long as the other chip uses the same type serial TTL interface. Just connect tx/rx, tx/rx, and gnd/gnd. I’ve used this type of setup with my ssc-32 servo controller.

Can I just clear the Arduino (empty void setup and void loop) and then connect RX and TX on the Arduino to their corresponding pin on the micro controller?

Even simpler is to just remove the AVR processor from it's socket, You are then free to wire pins 0 and 1 to the target board. You can even utilize the Arduino auto-reset (DTR) feature by running the Arduino reset pin to the target's reset pin.

Lefty