h8s-2111b Renesas Electronics Corporation., h8s-2111b Datasheet - Page 241

• Manufacturer Part Number: h8s-2111b
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family / H8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

10.5
10.5.1
Figure 10.5 shows the TCNT count timing with an internal clock source. Figure 10.6 shows the
TCNT count timing with an external clock source. The pulse width of the external clock signal
must be at least 1.5 system clocks (φ) for a single edge and at least 2.5 system clocks (φ) for both
edges. The counter will not increment correctly if the pulse width is less than these values.
10.5.2
The CMFA and CMFB flags in TCSR are set to 1 by a compare-match signal generated when the
TCNT and TCOR values match. The compare-match signal is generated at the last state in which
the match is true, just when the timer counter is updated. Therefore, when TCNT and TCOR
match, the compare-match signal is not generated until the next TCNT input clock. Figure 10.7
shows the timing of CMF flag setting.
φ
Internal clock
TCNT input
clock
TCNT
φ
External clock
input pin
TCNT input
clock
TCNT
Operation Timing
TCNT Count Timing
Timing of CMFA and CMFB Setting at Compare-Match
Figure 10.6 Count Timing for External Clock Input (Both Edges)
Figure 10.5 Count Timing for Internal Clock Input
N – 1
N – 1
N
N
Rev. 1.00, 05/04, page 207 of 544
N + 1
N + 1