This bit is the interrupt enable bit for a U-TIMER underflow.
[Bit 3] UNDR (UNDeR flow flag)
This bit is a flag indicating that an underflow has occurred. The UNDR bit is cleared at reset and when
"0" is written to it. For a read by a read modify write instruction, "1" is always read.
Writing "1" to the UNDR has no effect.
[Bit 2] CLKS (CLOCK Select)
In the MB91350A, always write "0" to this bit.
[Bit 1] UTST (U-TIMER STart)
This bit is the U-TIMER operation enable bit.
Interrupt disabled (initial value)
Stopped. Writing "0" during operation stops running of the U-TIMER. (initial value)
Operation. Writing "1" during operation does not stop the U-TIMER.