Renesas SH7781 - Manual (Page 842)

18. Timer Unit (TMU)
Rev.1.00 Jan. 10, 2008 Page 812 of 1658
REJ09B0261-0100
(3) TCNT Count Timing
• Operating on internal clock
Any of five internal count clocks (Pck/4, Pck/16, Pck/64, Pck/256, or Pck/1024) scaled from
the peripheral clock can be selected as the count clock by means of the TPSC2 to TPSC0 bits
in TCR.
Figure 18.4 shows the timing in this case.
Internal clock
Pck
TCNT N + 1 N N – 1
Figure 18.4 Count Timing when Operating on Internal Clock
• Operating on external clock
In channels 0, 1, and 2, the external clock input pin (TCLK) input can be selected as the timer
clock by means of the TPSC2 to TPSC0 bits in TCR. The detected edge (rising, falling, or both
edges) can be selected with the CKEG1 and CKEG0 bits in TCR.
Figure 18.5 shows the timing for both-edge detection.
External clock
input pin (TCLK)
Pck
TCNT N + 1 N N – 1
Figure 18.5 Count Timing when Operating on External Clock Input