Part Number: MSP430FR6989
The user guide for the 5xx and 6xx family (SLAU208) states that the state of the P1OUT register is undefined on reset, or in other words, "figure it out yourself." This definition is also applied to other output registers. Can somebody please elaborate on this?
This series of MCUs uses a power management module that forces us to lock and unlock the digital I/O in order to use them by using the LOCKLPM5 bit in PM5CTL0 register of the PMM module. So this might have some relation to an answer, but it's just speculation from my point of view. I prefer a concrete definition about the initial state.
As a side note, the output registers for many other MCUs are defined as Unchanged at reset. I've carried out some tests as to what might be the actual behavior is on the 6989, but without any conclusion.
