Key Interrupt; Noise Filter Function - Panasonic MN101L Series User Manual

3.3.4

Key Interrupt

Key interrupt (KEYIRQn) pin can be selected with the KEYIEN and KEYSEL. KEYIRQn is generated when one
of the KEYIRQ pins goes from "High" to "Low".
Setting example of KEYIRQ
The following example shows how to use P10, P11, P12 and P13 as KEYIRQ pins and generate IRQ7.
Step Settings
Set the input direction of
1
P10, P11, P12 and P13
2 Add the pull-up resistors
Set P10, P11, P12 and P13 as
3
KEYIRQ pins.
Set the Interrupt level of IRQ7
4
5 Enable IRQ7
3.3.5

Noise Filter Function

Noise Filter (NF) controlled with NFCTR01, NFCTR23, NFCTR45 and NFCTR67 is available to eliminate input
noise at the external interrupt pins (IRQn). NF samples the input signal at IRQn, and when the input signal is sam-
pled three times and the level of it is not changed, the signal can pass through NF.
NF Sampling timing
Input signal at IRQn
Signal passed through NF
NF cannot be used in STOP or HALT mode. When an IRQn is used as the trigger to return
from the STOP or HALT mode, NF of the IRQn must not be used.
.. ..
Register
P1DIR
P1PLUP
KEYSEL
KEYIEN
IRQ7ICR Set IRQ7ICR.LV1-0 as you like.
IRQ7ICR Set IRQ7ICR.IE to "1".
Figure:3.3.1 Eliminating input noise at IRQn with NF
Description
Set P1DIR.P1DIR3-0 to "0000".
Set P1PLUP.P1PLU3-0 to "1111".
Set KEYSEL.KEYSEL3-0 to "0000".
Set KEYIEN.KEYEN3-0 to "1111".
* IRQ7ICR.IR should be set to "0".
Chapter 3
Interrupts
External Interrupts III - 47