Noise Reduction For General Io Pins - Fujitsu F2MC-16LX Series Application Note

5. Noise reduction for general IO pins

To reduce noise, make sure to connect the Vss or Vcc with smoothed power supply,
because the noise on the power supply will also distributed via IO-pin, which is configured as
static low or high output. Figure 9 shows an example to reduce the noise on output lines.
µC
µC
IO-Port
IO-Port
Noise
length of trace length of trace
Figure 9: Place the series resistor close to IO pin because so will be reduced the noise
of output
Note: To reduce noise, make sure to connect unused input pins to Vss or Vcc (Use pull-down
or pull-up resistor, please check the DS of the microcontroller series).
Also, especially if CMOS Logic is used, floating gates could generate problems regarding high
input currents and latch up.
9