Operation; Frc Count Timing - Hitachi SH7095 Hardware User Manual

11.4

Operation

11.4.1

FRC Count Timing

The FRC increments according to the clock input (internal or external).
Internal Clock Operation: Set the CKS1 and CKS0 bits of the TCR to select which of the three
internal clocks created by dividing system clock φ (φ/8, φ/32, φ/128) is used. Figures 11.4 shows
the timing.
External Clock Operation: Set the CKS1 and CKS0 bits of the TCR to select the external clock.
The external clock begins counting on the rising edge. The pulse width of the external clock must
be at least 6 system clocks (φ). A smaller pulse width results in operation that is not always
accurate. Figures 11.5 shows the timing.
298 Hitachi
Figure 11.4 Count Timing (Internal Clock Operating)
Figure 11.5 Count Timing (External Clock Operating)