Subclock Waveform Generation Circuit; Note On Crystal Resonator - Hitachi H8S/2646 Hardware Manual

21.8

Subclock Waveform Generation Circuit

To eliminate noise from the subclock input to OSCI, the subclock is sampled using the dividing
clock ø. The sampling frequency is set using the NESEL bit of LPWRCR. For details, see section
22.2.3, Low-Power Control Register (LPWRCR).
No sampling is performed in sub-active mode, sub-sleep mode, or watch mode.
21.9

Note on Crystal Resonator

Since various characteristics related to the crystal resonator are closely linked to the user's board
design, thorough evaluation is necessary on the user's part, for the F-ZTAT version, using the
resonator connection examples shown in this section as a guide. As the resonator circuit ratings
will depend on the floating capacitance of the resonator and the mounting circuit, the ratings
should be determined in consultation with the resonator manufacturer. The design must ensure that
a voltage exceeding the maximum rating is not applied to the oscillator pin.
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