Chapter 5
Interrupt Controller
Noise Filter Function V - 47
5.4.8 Noise Filter Setup Example
■ Enable Noise Filter and Both-edge Setup Example
Noise remove function (noise filter function) is added to the input signal from P74 pin to generate the external
interrupt 0 (IRQ0) at the both-edge. The sampling clock is set to 1/8 of IOCLK.
The following shows the setup procedure and description.
Setup Procedure Description
(1) Disable the interrupt
G2ICR(0x00008908)
bp8: G2IE0=0
(1) Set the G2IE0 flag of the G2ICR register to “0” to disable
the interrupt.
(2) Set the interrupt generation condition (both-
edge detection)
IRQEDGESEL(0x0000A056)
bp0: IRQEG0=1
(2) Set the IRQEG0 flag of the edge detection register
(IRQEDGE) to “1” to set the both-edge detection.
(3) Set the sampling clock
NFCLK0(0x0000A050)
bp1-0: NFCK01-0=01
(3) Set the NFCK01-0 flag of the sampling clock setup
register 0 (NFCLK0) to “01” to set 1/8 sampling clock of
IOCLK.
(4) Setup the noise filter operation
NFCNT(0x0000A054)
bp0: NFCNT0=1
(4) Set the NFCNT0 flag of the noise filter control register
(NFCNT) to “1” for the noise filter operation to be valid.
(5) Set the interrupt generation condition (both-
edge detection)
EXTMD0(0x00008A80)
bp1-0: IR0TG1-0=00
(5) Set the IROTG1-0 flag of the external interrupt condition
specification register 0 (EXTMD0) to “00” to set the
rising edge. This flag should be set to the rising edge.
(6) Set the interrupt level
G2ICR(0x00008908)
bp14-12: G2LV2-0=100
(6) Set the interrupt level by the G2LV2-0 flag of the G2ICR
register. If the interrupt request flag has been already
set, clear the interrupt request flag.
(7) Enable the interrupt
G2ICR(0x00008908)
bp8: G2IE0=1
(7) Set the G2IE0 flag of the G2ICR register to “1” to enable
the interrupt.
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