I have noticed that the discussion on how to do RX/TX on the serial port on Connect ME, and similar platforms, comes back again. I am posting a small example that outlines the skeleton on how I did it. I had to remove and change things that relate to our product, so I dont get in trouble, but one can easily get the idea. This also means that the code will most likely not work as-is; I just dont have time to pats around with it, so you will have to do some work. Feel free to use it and abuse it - just do that at your own risk.
I used mutex locking to achieve transfer.
You can also look around for instructions on how to maximize the speed of the serial ports if you need they should be still floating in the posts, so I wont repeat them here.
I am not claming that this is the way to do it. It is only an example on how I did it using Digi examples and voodoo and got good results.
Just call the serial_threads_start is from your applicationStart.