Panasonic MN101C77C User Manual

Chapter 3    Interrupts

III - 52

External Interrupts

■

Noise Remove Function Operation (External interrupts 0 to 4)

After sampling the input signal to the external interrupt pins ( IRQ0 to IRQ4) by the set sampling time, if the

same level comes continuously three times, that level is sent to the inside of LSI. If the same level does not

come continuously three times, the previous level is sent. It means that only the signal with the width of

more than " Sampling time X 3 sampling clock " can pass through the noise filter, and other much narrower

signals are removed, because those are regarded as noise.

Noise filter can not be used at STOP mode, HALT mode and SLOW mode.

Sampling
timing

IRQn pin input signal

Waveform after
filtering noise 

0

0

1

1

1

1

1

0

0