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CHAPTER 14 MULTI-FUNCTIONAL TIMER
■ DTTI0 Pin Noise Cancellation Function
By setting bit5 (NRSL) of the waveform control register (SIGCR) to "1", the noise cancellation function for
DTTI0 pin input is enabled. When noise cancellation function is enabled, the time for fixing an output pin
RTO0 to RTO5 to inactive level is delayed for about 4, 8, 16 or 32 machine cycles (selected by
SIGCR:NWS1,NWS0). Since the noise cancellation circuit uses a peripheral clock, input is invalidated
even if the DTTI0 input is enabled in a mode such as STOP mode in which the oscillation stops.
■ DTTI0 Interrupt
When low level of DTTI0 is detected, DTTI0 interrupt flag (SIGCR:DTIF) is set to "1" after noise
cancellation time is passed and an interrupt request is sent to interrupt controller.
DTTI0
SIGCR: DTIF
Notes:
• If SIGCR:NWS1,NWS0 is changed within noise cancellation time, the larger value of NWS1,
NWS0 will take effect.
• SIGCR:DTIF can only be software clear.
348
Figure 14.6-30 DTTI0 Interrupt Timing
Noise cancellation time controlled
by SIGCR:NWS1,NWS0
Software write "0" in SIGCR: DTIF
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