Datasheet

Section 12 Timer W
Rev. 6.00 Mar. 24, 2006 Page 175 of 412
REJ09B0142-0600
The TCNT value can be captured into a general register (GRA, GRB, GRC, or GRD) when a
signal level changes at an input-capture pin (FTIOA, FTIOB, FTIOC, or FTIOD). Capture can
take place on the rising edge, falling edge, or both edges. By using the input-capture function, the
pulse width and periods can be measured. Figure 12.7 shows an example of input capture when
both edges of FTIOA and the falling edge of FTIOB are selected as capture edges. TCNT operates
as a free-running counter.
TCNT value
H'FFFF
H'1000
H'0000
FTIOA
GRA
Time
H'AA55
H'55AA
H'F000
H'1000 H'F000 H'55AA
GRB
H'AA55
FTIOB
Figure 12.7 Input Capture Operating Example