Noise Elimination; Analog Filtered Inputs; Digitally Filtered Inputs - NEC V850E/Dx3 Preliminary User's Manual

Pin Functions
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2.5 Noise Elimination

The input signals at some pins are passed through a filter to remove noise and
glitches. The microcontroller supports both analog and digital filters. The
analog filters are always applied to the input signals, whereas the digital filters
can be enabled/disabled by control registers.

2.5.1 Analog filtered inputs

The external interrupts INTP0...INTP7, NMI and the external RESET input are
passed through an analog filter to remove noise and glitches. The analog filter
suppresses input pulses that are shorter than a specified puls width (refer to
the Electrical Target Specification). This assures the hold time for the external
interrupt signals.
The analog filter operates in all modes (normal mode and standby modes). It is
only effective if the corresponding pin works in alternative input mode and not
as a general purpose I/O port.

2.5.2 Digitally filtered inputs

The inputs of the peripherals listed below are passed through a digital filter to
remove noise and glitches.
The digital filter operates in all modes, which have the PLL enabled. Thus, it
does not operate in Watch, Sub-watch and Idle mode. The digital filter is only
effective if the corresponding pin works in alternative input mode and not as a
general purpose I/O port.
The digital input filter is available for the following external signals:
Table 2-52 Digitally filtered external signals
Module Signal
CSIB0 SIB0, SCKB0
CSIB1 SIB1, SCKB1
CSIB2 SIB2, SCKB2
TMP0 TIP00, TIP01
TMP1 TIP10, TIP11
TMP2 TIP20, TIP21
TMP3 TIP30, TIP31
TMG0 TIG01 to TIG04
TMG1 TIG11 to TIG14
TMG2 TIG20 to TIG25
Note The Timers G provide additional digital noise filters at their capture inputs
TIGn1 to TIGn4. Refer also to the Electrical Target Specification for the
minimum capture inputs pulse widths.
Preliminary User's Manual U17566EE1V2UM00
Comment
For high clock rates of the Clocked Serial
Interface, the digital filter should be disabled.
Otherwise, desired input pulses may be
removed by the digital filter.
Chapter 2
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