HD6412240 RENESAS [Renesas Technology Corp], HD6412240 Datasheet - Page 416

• Manufacturer Part Number: HD6412240
• Description: Renesas 16-Bit Single-Chip Microcomputer H8S Family / H8S/2200 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

Section 10 8-Bit Timers
10.3
10.3.1
TCNT is incremented by input clock pulses (either internal or external).
Internal Clock
Three different internal clock signals ( /8, /64, or /8192) divided from the system clock ( ) can
be selected, by setting bits CKS2 to CKS0 in TCR. Figure 10.2 shows the count timing.
External Clock
Three incrementation methods can be selected by setting bits CKS2 to CKS0 in TCR: at the rising
edge, the falling edge, and both rising and falling edges.
Note that the external clock pulse width must be at least 1.5 states for incrementation at a single
edge, and at least 2.5 states for incrementation at both edges. The counter will not increment
correctly if the pulse width is less than these values.
Figure 10.3 shows the timing of incrementation at both edges of an external clock signal.
Rev.3.00 Mar. 26, 2007 Page 374 of 772
REJ09B0355-0300
Internal clock
Clock input
to TCNT
TCNT
Operation
TCNT Incrementation Timing
Figure 10.2 Count Timing for Internal Clock Input
N–1
N
N+1