Ah, I have perhaps been unclear.
Let me restate the problem without code getting the way:
seeeduino can not send bytes properly to irobot Create using hardware serial at 57600 baud, while arduino diecimila can. I have verified this using 2 arduino decimila and 1 seeeduino, and it would indicate the seeeduino has a timing issue that prevents it from being a drop-in replacement for the arduino decimila.
Note that this is the only time I have come across this incompatibility, in other Sketches the seeeduino behaves exactly like an arduino decimila.
So my question is, is there anything in the design of the seeeduino that could cause this incompatbility, or is it simply a case of my particular seeeduino being… less than optimal? Note that I am 99% certain my hardware serial is in no way damaged as it functions perfectly for all other serial based tasks I have been using it for.
Cheers,
Steve