3pi serial RX not working

I’ve been using my 3pi (purchased from Sparkfun) with the simple serial slave program. I soldered a header to the PD0/PD1 holes and have been able to successfully send/recieve commands and data. I boxed up the 3pi (in its original box) for a couple weeks, and when I got it out to work with it again it would not respond to any commands. My soldering skills aren’t very good, and the header wobbled somewhat, so I resoldered it. It still wouldn’t respond to any serial commands. Using a multimeter I found that there was no connection between the RX line of the header and the RX pin on the ATmega. The TX line is properly connected. The board dosen’t appear to be damaged. I’ve tried holding a wire in place in the unoccupied RX hole and sending data, it’s not recieved. Occasionally the 3pi will give random "Invalid command: " errors on the LCD when wiggling the header or wire.

Is there a way to fix this? Or is there another way to connect to the 3pi’s serial?


I am sorry you are having trouble with the RX pin on your 3pi. I suspect that there is a problem with your connection to RX since you indicated that you can generate invalid commands when you wiggle the header. Could you post a picture of your 3pi that clearly shows the RX and TX connections?