ok, i'm getting a handle on the interrupt handler. the DT_INTS is very powerful!

i'm not sure if i can use it, because my hardware USART is located on a port that i'm dedicating to parallel in/out data stream.

i will try using an interrupt on the pin that i'm dedicating to serial in, but i'm not sure it will react fast enough to catch the data. perhaps what i really need to do is get a bigger chip.
seems like over-kill, though.

back to the lab.