______
R8C/13 Group
10.2 INT Interrupt
_______
10.2.2 INT0 Input Filter
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The INT0 input has a digital filter which can be sampled by one of three sampling clocks. The sampling
clock is selected using the INT0F1 to INT0F0 bits in the INT0F register. The IR bit in the INT0IC
register is set to “1” (interrupt requested) when the sampled input level matches three times. When the
INT0F1 to INT0F0 bits are set to “012”, “102”, or “112”, the P4_5 bit in the P4 register indicates the
filtered value.
_____
Figure 10.11 shows the INT0 input filter configuration. Figure 10.12 shows an operation example of
_____
INT0 input filter.
INT0F1 to INT0F0
=01
=10
=11
2
f
f
f
1
Sampling clock
2
8
2
INT0EN
32
Other than
INT0F1 to INT0F0
=00
2
INT0 interrupt
P4_5 bit
Digital filter
(input level
matches 3x)
INT0
=00
2
Port P45
direction
register
INT0F0, INT0F1: Bits in INT0F register
INT0EN: Bit in INTEN register
______
Figure 10.11 INT0 Input Filter
P45 input
Sampling
timing
P4_5 in
P4 register
IR bit in
INT0IC register
This is an operation example when the INT0F1 to INT0F0 bits in the
Set to “0” in program
INT0F register is set to “01
2
”, “10
2
”, or “11
2
” (passing digital filter).
______
Figure 10.12 Operation Example of INT0 Input Filter
Rev.1.20 Jan 27, 2006 page 61 of 205
REJ09B0111-0120
RENESAS [ RENESAS TECHNOLOGY CORP ]
