HD6475328-CP10 Datasheet, PDF (155/459 Pages) Hitachi Semiconductor – original Hitachi CMOS microcomputer unit (MCU)

(2) External Clock Input
Frequency Double the system clock (ø) frequency
Duty factor 45% to 55%
8.3 System Clock Divider
The system clock divider divides the crystal oscillator or external clock frequency (fosc) by 2 to
create the ø clock.
An E clock signal is created by dividing the ø clock by 8. The E clock is used for interfacing to E
clock based devices.
Figure 8-6 shows the phase relationship of the E clock to the ø clock.
ø^φ
E^E
Figure 8-6 Phase Relationship of ø Clock and E Clock
138