Hitachi H8/3020, Hardware Manual

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490
External Clock: The external clock frequency should be equal to the system clock frequency (ø).
Table 16-3 and figure 16-6 indicate the clock timing.
Table 16-3 Clock Timing
V
CC
=
3.0 V to 3.6 V
Item Symbol Min Max Unit Test Conditions
External clock rise time t
EXr
— 10 ns Figure 16-6
External clock fall time t
EXf
— 10 ns
External clock input duty (a/t
cyc
) — 30 70 % ø
≥
5 MHz Figure 16-6
40 60 % ø < 5 MHz
ø clock width duty (b/t
cyc
) — 40 60 %
t
cyc
a
EXTAL
t
EXr
t
EXf
V
CC
×
0.5
t
cyc
b
ø V
CC
×
0.5
Figure 16-6 External Clock Input Timing