Renesas SH7781 - Manual (Page 843)

18. Timer Unit (TMU)
Rev.1.00 Jan. 10, 2008 Page 813 of 1658
REJ09B0261-0100
18.4.2 Input Capture Function
Channel 2 has an input capture function.
The procedure for using the input capture function is as follows:
1. Use bits TPSC2 to TPSC0 in TCR2 to set an internal clock as the timer operating clock.
2. Use bits IPCE1 and IPCE0 in TCR2 to specify use of the input capture function, and whether
interrupts are to be generated when this function is used.
3. Use bits CKEG1 and CKEG0 in TCR2 to specify whether the rising or falling edge of the
TCLK pin is to be used to set the TCNT value in TCPR2.
When input capture occurs, the TCNT2 value is set in TCPR2 only when the ICPF bit in TCR2 is
0. A new DMAC transfer request is not generated until processing of the previous request is
finished.
Figure 18.7 shows the operation timing when the input capture function is used (with TCLK rising
edge detection).
TCOR2
H'0000 0000
TCLK
TCPR2
TICPI2
TCNT2 value
TCPR2 value is set in TCNT2
on underflow
TCNT2 value is set
Time
Figure 18.6 Operation Timing when Using Input Capture Function