Does triggering of the GPIF change the state of the unused control lines?
No, triggering of the GPIF does not change the state of the unused control lines. This is an advantage in a situation when we are using only a few of the GPIF control lines. Let us say, of the 6 available control lines, we are using only 2 for GPIF and the rest 4 can be used for other purposes. When the GPIF is idle, we can manipulate (enable and drive a value) the state of the unused 4 control lines using the GPIFIDLECTL register. Even when the GPIF is triggered, the unused control lines will retain the value they were initialized to in the GPIFIDLECTL register.
Note: TRICTL is the 7th bit of the register GPIFCTLCFG which indicates the number of active outputs/tri-stating