
Table 4-3 Noise Canceller Sampling Lock
EINTCRx<INTxNC>
Sampling interval
00
fcgck
01
fcgck/22
10
fcgck/23
11
fcgck/24
INTi pin
Signal after noise removal
i=1 to 3
Noise
Signal
Figure 4-5 Noise Cancel Operation
In SLOW1/2 or SLEEP1 mode, a signal is sampled by the low frequency clock divided by 4. If the same
level is detected twice consecutively, the signal is recognized as a signal.
In IDLE0, SLEEP0 or STOP mode, the noise canceller sampling operation is stopped and an external
interrupts are unavailable. When operation returns to NORMAL1/2, IDLE1/2, SLOW1/2 or SLEEP1 mode,
sampling operation restarts.
Note 1: If noise is input consecutively during sampling of external interrupt pins, the noise cancel function does
not work properly. Set EINTCRx<INTxNC> according to the cycle of externally input noise.
Note 2: If an external interrupt pin is used as an output port, the input signal to the port is fixed to "L" when the
mode is switched to the output mode, and thus an interrupt request occurs. To use the pin as an output
port, clear the corresponding interrupt enable register to "0" to disable the generation of interrupt.
Note 3: Interrupt requests may be generated during transition of the operation mode. Before changing the op-
eration mode, clear the corresponding interrupt enable register to "0" to disable the generation of
interrupt. When the operation mode is changed from NORMAL1/2 or IDLE1/2 to SLOW1/2 or SLEEP1,
wait 12/fs [s] after the operation mode is changed and clear the interrupt latch. And when the operation
mode is changed from SLOW1/2 or SLEEP1 to NORMAL1/2 or IDLE1/2, wait 2/fcgck+3/fspl [s] after the
operation mode is changed and clear the interrupt latch.
4.3.4
External interrupt 4
External interrupt 4 detects the falling edge, the rising edge, both edges or "H" level of the INT4 pin and
generates interrupt request signals.
4.3.4.1
Interrupt request signal generating condition detection function
Select an interrupt request signal generating condition at EINTCR4<INT4ES> for external interrupt 4.
Table 4-4 Selection of Interrupt Request Generation Edge
EINTCR4<INT4ES>
Detected at
00
Rising edge
01
Falling edge
10
Both edges
11
"H" level interrupt
TMP89FH42
4. External Interrupt control circuit
4.3 Function
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