Fujitsu F2MCTM-16LX User Manual

274

CHAPTER 15  WATCH TIMER

Bit Name

Function

bit7

WDCS: 
Watchdog clock select bit

This bit selects the operation clock of the watchdog timer.
<Main clock mode or PLL clock mode>
When set to "0": Selects output of watch timer as operation clock of watchdog timer.
When set to "1": Selects output of timebase timer as operation clock of watchdog timer.
<Subclock mode>
Always set this bit to 0 to select the output of the watch timer. 
Note:

The watch timer and the timebase timer operate asynchronously. When the WDCS bit is 
changed from 0 to 1, the watchdog timer may run fast. The watchdog timer must be 
cleared before and after changing the WDCS bit.

bit6

SCE: 
Oscillation stabilization wait 
time end bit

This bit indicates that the oscillation stabilization wait time of the subclock ends.
When cleared to "0": Subclock in oscillation stabilization wait state
When set to "1" : Subclock oscillation stabilization wait time ends

•

The oscillation stabilization wait time of the subclock is fixed at 2

14

 /SCLK (SCLK: 

subclock frequency).

bit5

WTIE: 
Overflow interrupt enable bit

This bit enables or disables generation of an interrupt request when the watch timer counter 
overflows (carries).
When set to "0": Interrupt request not generated even at overflow (WTOF=1)
When set to "1": Interrupt request generated at overflow (WTOF = 1)

bit4

WTOF: 
Overflow flag bit

This bit is set to "1" when the counter value of the watch timer reaches the value set by the 
interval time select bit.
When an overflow carry occurs (WTOF = 1) with interrupt request enabled (WTIE = 1), an 
interrupt request is generated.
When set to "0": Clears watch timer counter
When set to "1": No effect
•

The overflow flag bit is set to "1" when the bit of the watch timer counter corresponding 
to the interval time set by the interval time select bits (WTC2 to WTC0) overflows (car-
ries).

bit3

WTR: 
Watch timer clear bit

This bit clears the watch timer counter.
When set to "0": Clears watch timer counter to "0000

H

".

When set to "1": No effect
Read: 1 is always read.

bit2

to

bit0

WTC2, WTC1, WTC0: 
Interval time select bits

These bits set the interval time of the watch timer.
•

When the interval time set by the WTC2 to WTC0 bits is reached, the corresponding bit 
of the watch timer counter overflows (carries) and the overflow flag bit is set 
(WTC:WTOF = 1).

•

To set the WTC2 to WTC0 bits, set the WTOF bit to 0.