Duemilanove board as a usb serial converter?

Hi,

Maybe the answer to this should be obvious, but I'm just wondering if the Arduino Duemilanove board can be used as a regular usb-serial converter? i.e. Can I connect a serial device to the Tx, Rx, +5v and Gnd connectors, to communicate with a PC?

Thanks for any help,

Cheers,

Jim.

Yes, but remove the microcontroller chip first!

Yes, but remove the microcontroller chip first!

Or just wire a jumper from a ground pin to the reset pin, that disable the AVR chip and you are free to use the Rx,Tx, +5vdc and ground pins externally to the board.

Lefty

.. why did I not think of that???

Yes, but remove the microcontroller chip first!

No need to remove the microcontroller chip or add jumper if you are just using the Arduino board for serial communication (that is, you are not using the on-board ATMega328P).

I used Arduino as a usb-serial converter to interface with DS89C430 before (http://www.kerrywong.com/2010/06/13/invoking-ds89c430-45-rom-loader-using-arduino/)

No need to remove the microcontroller chip or add jumper if you are just using the Arduino board for serial communication (that is, you are not using the on-board ATMega328P).

I disagree. Everytime the Arduino board is powered up it will jump into the bootloader and twiddle with the serial pins. This could 'confuse' the external device or PC that are using the serial link. Best to disable the AVR chip.

Lefty

Best to disable the AVR chip.

Fair enough. You are absolutely correct, depending on what you use this USB/Serial interface for you may need to disable the chip. But for the majority of applications, I haven't had any issues with not disabling the on board ATMega328.

My reasoning is that the bootloader interact with the Rx/Tx line only during the first few seconds of the initial power up, so if you can avoid using the serial port during that period of time, you should be OK (according to my experience). That said, whatever the program is on your AVR should definitely not use any Serial routines.

Maybe the answer to this should be obvious, but I’m just wondering if the Arduino Duemilanove board can be used as a regular usb-serial converter? i.e. Can I connect a serial device to the Tx, Rx, +5v and Gnd connectors, to communicate with a PC?

If your device has TTL tx/rx lines, then there should not be a problem. The pc will just see the device the same as it sees the chip on the arduino. Load a non serial script into the arduino so it won’t interfer with any of the communications between the pc and the device.

Load a non serial script into the arduino so it won't interfer with any of the communications between the pc and the device.

Except there is this ugly bootloader which tries to communicate after each change of the DTR line... I think this has been discussed already twice in this thread ;-)

Except there is this ugly bootloader which tries to communicate after each change of the DTR line... I think this has been discussed already twice in this thread

Well, the OP JimGurney hasn't mentioned having an issue with this. If it is a problem rather than a "talking point" then either cut the dtr trace, use software that does not twittle the dtr line, short the dtr line to ground, or buy a USB serial adapter and don't use the dtr line. ;)