HD6433937 Datasheet, PDF (102/521 Pages) Hitachi Semiconductor – Hardware Manual

3. External clock input
Connect the external clock to the DX₁ pin and leave the DX₂ pin open, as shown in figure 4-10.
DX ₁
DX ₂
Open
External clock input
Frequency
Duty
Figure 4-10 Pin Connection when Inputting External Clock
Subclock (øw)
45% to 55%
90