SH7615 Datasheet, PDF (575/925 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperH
RISC engine Family/SH7600 Series

12.4 Operation
12.4.1 FRC Count Timing
The FRC increments on clock input (internal or external).
Internal Clock Operation: Set the CKS1 and CKS0 bits in TCR to select which of the three
internal clocks created by dividing system clock φ (φ/8, φ/32, φ/128) is used. Figure 12.4 shows
the timing.
Pφ
Internal clock
FRC input
clock
FRC N – 1
N
N+1
Figure 12.4 Count Timing (Internal Clock Operation)
External Clock Operation: Set the CKS1 and CKS0 bits in TCR to select the external clock.
External clock pulses are counted on the rising edge. The pulse width of the external clock must be
at least 6 system clocks (φ). A smaller pulse width will result in inaccurate operation. Figures 12.5
shows the timing.
Pφ
External clock
input pin
FRC input
clock
FRC
N
N+1
Figure 12.5 Count Timing (External Clock Operation)
Rev. 2.00, 03/05, page 537 of 884