I am interested.
Please format your code:
I can’t look at the code as is and unable to cut and past working code (try and you will see why).
I have been looking into the use of multiple serial ports and was planning to explore this further this weekend.
Please provide code on Arduino side; enough that I get a sense of format sent and any delays so I can simulate.
I have access to many Arduinos.
I suspect that you are trying to acquire and send data (< 60Hz from code comments) to Processing faster than the draw frame rate (50 Hz set by you) and that the serial port reads in the draw loop are “blocking”.
You may want to consider:
You can do a search and find examples for this in the forums.