Go Down

Topic: uploading new sketches to occupied UART ports (Read 1 time) previous topic - next topic


Hi all,
I'm having a bit of difficulty even getting a sensible subject header, but let's hope my question makes more sense!

My setup: I have an arduino pro mini. I usually upload sketches by connecting to the pins at the end of the board. I am only connected to the pins at the end when uploading sketches...otherwise they are open. At the same time I have an xbee attached to the Tx & Rx pins on the side (it's just an alternate location to connect to the same UART pins on the chip). In addition I usually have some other device (e.g compass or rfid reader) attached to the other pins on the arduino and communicate via newsoftserial.

The set-up works great while it's running. The problem, however, is when I want to upload a new sketch. Due to the crazy physical space limitations these devices need to live in, I usually have to solder the wires directly to the boards...often takes up considerably less space than using jumpers and the like. Since the xbee is permanently connected to the Tx & Rx UART pins, I get errors when trying to upload new sketches using the open UART pins, usually something along the line of unable to communicate to the arduino. I am assuming it's because data is flowing to the xbee as well.

So the question: is there a way to have the xbee permanently attached to the Tx and Rx pins, and still be able to upload sketches to the mini? A cleverly placed resistor or diode or ??

Thanks in advance for any advice, and please let me know if any of the above doesn't make sense. I seem to be struggling with how to word the question.



I think it would work if you could cut power to the Xbee, while uploadeing your sketch. Maybee a little toggle switch could do the trick.


Hi MikMo,
Thanks for your reply. Unfortunately I haven't had any success with that...still seems to "bypass" the mini which is why I'm thinking an inline resistor might help here to ensure the sketch goes to the mini and not beyond. I just don't know if this is smart, tho.



In line resistors would be good. However, they would not stop the signals sent to the Arduino going to the Xbee but would prevent the Xbee holding up the lines and stopping thinks getting through to the arduino.

However, I would recommender a DPCO switch (Dual Pole Change Over) on the serial lines. That's what I do when I am working with MIDI and I want to upload sketches.

Go Up