Fujitsu MB90390 Series Hardware Manual page 271

Table 15.2-2 Timer Control Register (Upper)
Bit name
bit15, bit13,
INTE3 to INTE0
bit11, bit9
bit14, bit12,
INT3 to INT0
bit10, bit8
INTE3 to INTE0 are the interrupt flags. They are set when the second counter, minute
counter and hour counter overflow respectively. If a INT bit is set while the
corresponding INTE bit is "1", the Watch Timer signals an interrupt. These flags are
intended to signal an interrupt every second/minute/hour/day.
Writing "0" to the INT bits clears the flags and writing "1" does not have any effect.
Any read-modify-write (RMW) instruction performed on the INT bit results reading
"1".
INT3 to INT0 are the interrupt flags. They are set when the second counter, minute
counter and hour counter overflow respectively. If a INT bit is set while the
corresponding INTE bit is "1", the Watch Timer signals an interrupt. These flags are
intended to signal an interrupt every second/minute/hour/day.
Writing "0" to the INT bits clears the flags and writing "1" does not have any effect.
Any read-modify-write (RMW) instruction performed on the INT bit results reading
"1".
CHAPTER 15 WATCH TIMER
Function
243