Input Capture Function; Figure 12.6 Count Timing When Operating On On-Chip Rtc Output Clock - Hitachi SH7750 Hardware Manual

• Operating on on-chip RTC output clock
The on-chip RTC output clock can be selected as the timer clock in channels 0 to 2 by means
of the TPSC2–TPSC0 bits in TCR. Figure 12.6 shows the timing in this case.
RTC output clock
TCNT

Figure 12.6 Count Timing when Operating on On-Chip RTC Output Clock

12.3.2

Input Capture Function

Channel 2 has an input capture function.
The procedure for using the input capture function is as follows:
1. Use the TCOE bit in the timer output control register (TOCR) to set the TCLK pin to input
mode.
2. Use bits TPSC2–TPSC0 in the timer control register (TCR) to set an internal clock or the on-
chip RTC output clock as the timer operating clock.
3. Use bits IPCE1 and IPCE0 in TCR to specify use of the input capture function, and whether
interrupts are to generated when this function is used.
4. Use bits CKEG1 and CKEG0 in TCR to specify whether the rising or falling edge of the
TCLK signal is to be used to set the timer counter (TCNT) value in the input capture register
(TCPR2).
This function cannot be used in standby mode.
When input capture occurs, the TCNT2 value is set in TCPR2 only when the ICPF bit in TCR2 is
0. Also, a new DMAC transfer request is not generated until processing of the previous request is
finished.
Figure 12.7 shows the operation timing when the input capture function is used (with TCLK rising
edge detection).
N + 1 N N – 1
Rev. 6.0, 07/02, page 307 of 986