HD6413008F RENESAS [Renesas Technology Corp], HD6413008F Datasheet - Page 256

• Manufacturer Part Number: HD6413008F
• Description: Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series
• Manufacturer: RENESAS [Renesas Technology Corp]

8. 16-Bit Timer
• 16TCNT count timing
Rev.4.00 Aug. 20, 2007 Page 212 of 638
REJ09B0395-0400
φ
Internal
clock
16TCNT input
clock
16TCNT
⎯ Internal clock source
⎯ External clock source
GR
H'0000
STR bit
IMF
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 8.15 shows the timing.
The external clock pin (TCLKA to TCLKD) can be selected by bits TPSC2 to TPSC0 in
16TCR, and the detected edge 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.
Figure 8.16 shows the timing when both edges are detected.
16TCNT value
N − 1
Figure 8.15 Count Timing for Internal Clock Sources
Figure 8.14 Periodic Counter Operation
N
Counter cleared by general
register compare match
Time
N + 1