CHAPTER 12 PORT FUNCTIONS
585
User’s Manual U15195EJ5V0UD
12.5.3 Timer 2 input pins
A noise eliminator using analog filtering and digital filtering using clock sampling are added to the timer 2 input
pins. A signal input that changes in less than this elimination time is not accepted internally.
Digital Filter
Pin
Analog Filter Noise
Elimination Time
Noise Elimination Time
Sampling Clock
P20/TI2/INTP20
P21/TO21/INTP21 to P24/TO24/INTP24
P25/TCLR2/INTP25
10 to 100 ns
4 to 5 clocks
f
XXTM2
Cautions 1. Since digital filtering uses clock sampling, if it is selected, input signals are not received
when the CPU clock is stopped.
2. The noise eliminator is valid only in control mode.
3. Refer to Figure 12-15 for an example of a noise eliminator.
Remark
f
XXTM2
: Clock of TM20 and TM21 selected in PRM02 register (be sure to set PRM02 = 01H)