HD6433044 Hitachi Semiconductor, HD6433044 Datasheet - Page 646

• Manufacturer Part Number: HD6433044
• Description: (HD64 Series) Hitachi Single-Chip Microcomputer
• Manufacturer: Hitachi Semiconductor

External Clock: The external clock frequency should be equal to the system clock frequency
(ø) when not divided by the on-chip frequency divider. Table 19-3, figures 19-6 and 19-7
indicate the clock timing.
When the appropriate external clock is input via the EXTAL pin, its waveform is corrected by
the on-chip oscillator and duty adjustment circuit. The resulting stable clock is output to
external devices after the external clock settling time (t
The system must remain reset with the reset signal low during t
unstable.
Table 19-3 Clock Timing
Item
External clock input
low pulse width
External clock input
high pulse width
External clock rise
time
External clock fall
time
Clock low pulse
width
Clock high pulse
width
External clock
output settling
delay time
Note: * t
DEXT
includes 10 t
Symbol
t
t
t
t
t
t
t
EXL
EXH
EXr
EXf
CL
CH
DEXT
*
cyc
of
Min
40
40
—
—
0.4
80
0.4
80
500
RES (t
V
2.7 V to 5.5 V
CC
=
RESW
Max
—
—
10
10
0.6
—
0.6
—
—
).
637
V
Min
20
20
—
—
0.4
80
0.4
80
500
CC
DEXT
= 5.0 V ± 10%
) has passed after the clock input.
Max
—
—
5
5
0.6
—
0.6
—
—
DEXT
, while the clock output is
Unit Test Conditions
ns
ns
ns
ns
t
ns
t
ns
µs
cyc
cyc
Figure 19-6
ø ≥ 5 MHz
ø < 5 MHz
ø ≥ 5 MHz
ø < 5 MHz
Figure 19-7
Figure
21-7