HD6475348R Datasheet, PDF (155/487 Pages) Hitachi Semiconductor – Single-Chip Microcomputer

Not allowed
CL2
Signal A Signal B
H8/534
H8/536
XTAL
EXTAL
CL1
Figure 8-4 Notes on Board Design around External Crystal
Input of External Clock Signal
(1) Circuit Configuration (HD6475368R, HD6475348R, HD6435368R, HD6435348R): When
using an external clock, input complementary clock signals to the EXTAL and XTAL pins as
shown in figure 8-5. Make sure the external clock does not go high during standby mode.
EXTAL
XTAL
74HC04
External clock input
Figure 8-5 External Clock Input (Example)
(2) External Clock Input
Fig. 8-5
Frequency Double the system clock (ø) frequency
Duty cycle 45% to 55%
Note: Mask-ROM versions can operate on external clock input
to the EXTAL pin alone, with the XTAL pin left open.
ZTAT™ versions can also operate with the XTAL pin left
open if the external clock frequency is 16 MHz or less.
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