Panasonic F77G, MN101C77C user manual Noise Filter, Noise Remove Function

Models: F77G MN101C77C

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Chapter 3 Interrupts

3-3-7 Noise Filter

Noise Filter (External interrupts 0 to1)

Noise filter reduce noise by sampling the input waveform from the external interrupt pins (IRQ0, IRQ1). Its sampling cycle can be selected from 4 types (fosc, fosc/28, fosc/29, fosc/210).

Noise Remove Selection (External interrupts 2 to 4)

Noise filter reduce noise by sampling the input waveform from the external interrupt pins (IRQ2 to IRQ4). Its sampling cycle is fosc.

Noise Remove Selection (External interrupts 0 to 4)

Noise remove function can be selected by setting the NFnEN flag of the noise filter control register (NFCTR) to "1".

Table 3-3-3 Noise Remove Function

NFnEN

0

1

 

 

 

IRQ0 input (P20)

IRQ0 Noise filter OFF

IRQ0 Noise filter ON

 

 

 

IRQ1 input (P21)

IRQ1 Noise filter OFF

IRQ1 Noise filter ON

 

 

 

IRQ2 input (P22)

IRQ2 Noise filter OFF

IRQ2 Noise filter ON

 

 

 

IRQ3 input (P23)

IRQ3 Noise filter OFF

IRQ3 Noise filter ON

 

 

 

IRQ4 input (P24)

IRQ4 Noise filter OFF

IRQ4 Noise filter ON

 

 

 

Sampling Cycle Setup (External interrupts 0 and 1)

The sampling cycle of noise remove function can be set by the NFnSCK 1- 0 flag of the NFCTR register.

Table 3-3-4 Sampling Cycle / Time of Noise Remove Function

NFnCKS1

NFnCKS0

Sampling

 

High-Speed oscillation

 

 

 

 

 

cycle

fosc=20 MHz

fosc=8 MHz

 

 

 

 

 

 

 

 

 

0

0

fosc

20 MHz

50 ns

8 MHz

125 ns

 

 

 

 

 

 

1

fosc/28

78.13 kHz

12.80 s

31.25 kHz

32 s

 

1

0

fosc/29

39.06 kHz

25.60 s

15.62 kHz

64 s

1

fosc/210

19.53 kHz

51.20 s

7.81 kHz

128 s

 

External Interrupts

III - 51

Page 145
Image 145
Panasonic F77G, MN101C77C user manual Noise Filter, Sampling Cycle / Time of Noise Remove Function