HD6432633 Datasheet, PDF (1023/1453 Pages) Renesas Technology Corp – Series of Microcomputers (MCUs: microcomputer units)

(2) Handling pins when subclock not required
If no subclock is required, connect the OSC1 pin to Vcc and leave OSC2 open, as shown in figure
23A-10.
VCC
OSC1
OSC2
Open
Figure 23A-10 Pin Handling When Subclock Not Required
23A.8 Subclock Waveform Shaping Circuit
To eliminate noise from the subclock input to OSC1, the subclock is sampled using the dividing
clock ø. The sampling frequency is set using the NESEL bit of LPWRCR. For details, see section
24.2.3, Low-Power Control Register (LPWRCR).
No sampling is performed in sub-active mode, sub-sleep mode, or watch mode.
23A.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 both the mask ROM versions and
F-ZTAT versions, 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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