HD6413007F20 Datasheet, PDF (350/798 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series

9. 16-Bit Timer
16TCNT value
GR
Counter cleared by general
register compare match
H'0000
Time
STR bit
IMF
Figure 9.14 Periodic Counter Operation
• 16TCNT count timing
⎯ Internal clock source
Bits TPSC2 to TPSC0 in 16TCR select the system clock (φ) or one of three internal clock
sources obtained by prescaling the system clock (φ/2, φ/4, φ/8).
Figure 9.15 shows the timing.
φ
Internal
clock
16TCNT input
clock
16TCNT
N−1
N
N+1
Figure 9.15 Count Timing for Internal Clock Sources
⎯ External clock source
Bits TPSC2 to TPSC0 in 16TCR select an external clock input pin (TCLKA to TCLKD),
and its valid edge or edges are selected by bits CKEG1 and CKEG0. The rising edge,
falling edge, or both edges can be selected.
The pulse width of the external clock signal must be at least 1.5 system clocks when a
single edge is selected, and at least 2.5 system clocks when both edges are selected. Shorter
pulses will not be counted correctly.
Rev.5.00 Sep. 12, 2007 Page 320 of 764
REJ09B0396-0500