NEC PD703114 User Manual page 582

Noise elimination clock
Input signal
Internal signal
Timers 1, 2, 3 rising
edge detection
Timers 1, 2, 3 falling
edge detection
Caution If there are three or less noise elimination clocks while the timer 1 or 3 input signal is high
level (or low level), the input pulse is eliminated as noise. If it is sampled at least four times,
the edge is detected as valid input.
582
CHAPTER 12 PORT FUNCTIONS
Figure 12-15. Example of Noise Elimination Timing
2 clocks 2 clocks 3 clocks 3 clocks
User's Manual U15195EJ5V0UD
4 clocks 4 clocks 5 clocks 5 clocks