Hitachi H8/3035 Series Hardware Manual page 395

External Clock: The external clock frequency should be equal to the system clock frequency
(ø). Table 15-3 and figure 15-6 indicate the clock timing.
Table 15-3 Clock Timing
Item Symbol
External clock rise t
EXr
time
External clock fall t
EXf
time
External clock input —
duty (a/t )
cyc
ø clock duty(b/t ) —
cyc
EXTAL
ø
Table 15-4 and Figure 15-7 show the timing for the external clock output stabilization delay
time. The oscillator and duty correction circuit have the function of regulating the waveform of
the external clock input to the EXTAL pin. When the specified clock signal is input to the
V = 2.7 V to
CC
5.5 V
Min Max
— 10
— 10
30 70
40 60
40 60
t
a
t
EXr
t
b
Figure 15-6 External Clock Input Timing
V = 5.0 V
CC
±10%
Min Max Unit
— 5 ns
— 5 ns
30 70 %
40 60 %
40 60 %
cyc
t
EXf
cyc
Test Conditions
Figure 15-6
ø ≤ 5
Figure
MHz 15-6
ø < 5
MHz
× 0.5
V
CC
× 0.5
V
CC
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