h8s-2138 Renesas Electronics Corporation., h8s-2138 Datasheet - Page 341

• Manufacturer Part Number: h8s-2138
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

11.3
11.3.1
FRC increments on a pulse generated once for each period of the selected (internal or external)
clock source.
Internal Clock: Any of three internal clocks ( /2, /8, or /32) created by division of the system
clock ( ) can be selected by making the appropriate setting in bits CKS1 and CKS0 in TCR.
Figure 11.3 shows the increment timing.
External Clock: If external clock input is selected by bits CKS1 and CKS0 in TCR, FRC
increments on the rising edge of the external clock signal.
The pulse width of the external clock signal must be at least 1.5 system clock ( ) periods. The
counter will not increment correctly if the pulse width is shorter than 1.5 system clock periods.
Figure 11.4 shows the increment timing.
Internal
clock
FRC input
clock
FRC
Operation
FRC Increment Timing
Figure 11.3 Increment Timing with Internal Clock Source
N – 1
N
Rev. 4.00 Jun 06, 2006 page 287 of 1004
Section 11 16-Bit Free-Running Timer
REJ09B0301-0400
N + 1