I'm guessing it's the second thing.
At the moment I'm not parsing data at all. Just printing values from the serial receive object in Max/MSP. After a few seconds it stops altogether. (the TX/RX lights go out on the Xbee RX shield).
This also happens in serial monitor. It's also super unresponsive when connected directly. Like if I'm not using the XBee and just have the sensor Arduino connected over USB, it's nearly impossible to change the baud rate, or move/close the serial monitor window.
In doing some searching on the forum I see serial.available() and serial.flush() come up a bunch. I'm wondering if I should use something like that?
One thing that did occur to me is that I'm hitting the serial read object in Max/MSP at 10ms. I don't know if that's connected to the RX arduino/xbee buffer, or just a matter of how often I check the buffer.
As in, if I increase that rate (say to 5ms or lower) will it empty out the serial buffer twice as fast, or just read from it twice as fast?
I've disconnected the XBee from the arduino in order to program the Arduino, so I can't test that last thing out just now. (Is it normal that you can't program the Arduino if an Xbee (which isn't powered up) is connected to the rx/tx pins).