Help with serial communication

Hi, so I’m trying to get a Firefly 2_2 to communicate with the 3Pi robot. For the firefly, I have it constantly do
putchar(‘a’), which it outputs serially. I have it correctly linked up with 3Pi’s serial ports, and am running the serial-slave example code. However, that is not working: my code seems to be stuck in the while loop of the read_next_byte() method… which makes me think that the polulu bot is not receiving the 'a’s even though I tested that the firefly outputs the correct char. Any idea why?


It looks like the Firefly 2_2 runs at 3.3V; are you level shifting the serial lines? Can you explain all of your connections between the 3pi Robot and the Firefly 2_2 and any other modifications you have made to either device? A picture of your setup might also be helpful.

- Ryan