Test Input Signal Acknowledgment Operation - NEC mPD780208 Subseries User Manual

(1) Interrupt request flag register (IF0H)
This register indicates whether a watch timer overflow is detected or not.
IF0H is set with a 1-bit or 8-bit memory manipulation instruction.
RESET input clears IF0H to 00H.
Figure 16-18. Format of Interrupt Request Flag Register 0H
Symbol 7 6
IF0H 0 0
(2) Interrupt mask flag register (MK0H)
This register is used to set the standby mode enable/disable at the time the standby mode is released by the
watch timer.
MK0H is set with a 1-bit or 8-bit memory manipulation instruction.
RESET input sets MK0H to FFH.
7 6
Symbol
MK0H 1 1 WTMK

16.5.2 Test input signal acknowledgment operation

The internal test input signal (INTWT) is generated when the watch timer overflows. This signal sets the WTIF
flag. At this time, the standby release signal is generated if it is not masked by the interrupt mask flag (WTMK). By
checking the WTIF flag in a cycle shorter than the overflow cycle of the watch timer, a watch function can be realized.
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CHAPTER 16 INTERRUPT AND TEST FUNCTIONS
<5> <4> <3> <2>
WTIF KSIF ADIF TMIF2
Figure 16-19. Format of Interrupt Mask Flag Register 0H
<5> <4> <3> <2>
KSMK ADMK
TMMK2
User's Manual U11302EJ4V0UM
<1> <0> Address
TMIF1 TMIF0 FFE1H
WTIF Watch timer overflow detection flag
0 No detection
1
Detection
<1> <0> Address
FFE5H
TMMK1 TMMK0
WTMK Standby mode control by watch timer
0 Standby mode release enabled
1
Standby mode release disabled
After reset R/W
00H R/W
After reset R/W
FFH R/W