HD6473258CP10 Datasheet, PDF (236/301 Pages) Renesas Technology Corp – Hitachi Single-Chip Microcomputer

Not allowed
CL2
Signal A Signal B
H8/325 series
XTAL
EXTAL
CL1
Figure 14-4. Notes on Board Design around External Crystal
(2) Input of External Clock Signal
Œ Circuit Configuration: Figure 14-5 shows examples of signal con^Fnⁱe^gc¹ti⁴o^-n⁴s for external clock
input. In example (b), the external clock signal should be held high during the standby modes.
(a)
(b)
EXTAL
XTAL
74HC04
External
clock
input
EXTAL
XTAL
Open
External
clock
input
Figure 14-5. External Clock Input (Example)
 External Clock Input
Frequency
Duty factor
Double the system clock (Ø) frequency
45% to 55%
233
Fig 14-5