HD6417750 Datasheet, PDF (358/1039 Pages) Renesas Technology Corp – SuperH RISC engine

TCNT Count Timing:
• Operating on internal clock
Any of five count clocks (Pφ/4, Pφ/16, Pφ/64, Pφ/256, or Pφ/1024) scaled from the peripheral
module clock can be selected as the count clock by means of the TPSC2–TPSC0 bits in TCR.
Figure 12.4 shows the timing in this case.
Pφ
Internal clock
TCNT
N+1
N
N–1
Figure 12.4 Count Timing when Operating on Internal Clock
• Operating on external clock
For channels 0 to 2, external clock pin (TCLK) input can be selected as the timer clock by
means of the TPSC2–TPSC0 bits in TCR. The rising edge, falling edge, or both edges can be
selected as the detected edge of the external clock with the CKEG1 and CKEG0 bits in TCR.
Figure 12.5 shows the timing for both-edge detection.
Pφ
External clock
input pin
TCNT
N+1
N
N–1
Figure 12.5 Count Timing when Operating on External Clock
Rev. 6.0, 07/02, page 306 of 986