Watch Timer Interrupt - Fujitsu MB90895 Series Hardware Manual

9.4

Watch Timer Interrupt

When the interval time is reached with the watch timer interrupt enabled, the overflow
flag bit is set to 1 and an interrupt request is generated.
I Watch Timer Interrupt
Table 9.4-1 shows the interrupt control bits and interrupt factors of the watch timer.
Table 9.4-1 Interrupt Control Bits of Watch Timer
Interrupt Factor
Interrupt request flag bit
Interrupt factor enable bit
• When the value set by the interval time select bits (WTC2 to WTC0) in the watch timer control register
(WTC) is reached, the overflow flag bit in the WTC register is set to 1 (WTC: WTOF = 1).
• When the overflow flag bit is set (WTC: WTOF = 1) with the watch timer interrupt enabled (WTC:
WTIE = 1), an interrupt request is generated.
• At interrupt processing, set the WTOF bit to "0" and cancel the interrupt request.
I Watch Timer Interrupt and EI
• The watch timer does not correspond to the EI
• For details of the interrupt number, interrupt control register, and interrupt vector address, see 3.5
Interrupt.
Interval time of watch timer counter
WTC:WTOF (overflow flag bit)
WTC: WTIE
2
OS Function
2
OS function.
CHAPTER 9 Watch timer
Watch timer
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