Datasheet

Section 13 Timer W
Rev. 3.00 Mar. 15, 2006 Page 197 of 526
REJ09B0060-0300
By setting a general register as an input-capture register, 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 13.7 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 13.7 Input Capture Operating Example