Chapter 7 AC Zero-Cross Circuit/Noise Filter
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7-3 Noise Filter

7-3-1 Overview

External interrupt pins IRQ0 and IRQ1 contain noise filtering circuit. This

circuitry can be used for remote control signal reception.

Figure 7-3-1 Noise Filtering Circuit Block Diagram

Noise Filter
Data bus
NFCTR
NF1EN
NF1CKS0
fs/28
fs/22
fs/29
fs/210
MUX
Noise filter
To IRQ0
interrupt
P20/IRQ0
MUX
NF0CKS1
NF0CKS0
NF0EN
NF1CKS1
2
2
MUX
Noise filter
To IRQ1
interrupt
P21/IRQ1/SENS
MUX
0
7
fs/28
fs/22
fs/29
fs/210
AC zero-cross
circuit
(Fig.7-1-1)
IRQ0: External interrupt 0
IRQ1: External interrupt 1