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Prescaler W can be reset by setting 1s in bits TMA3 and TMA2 of timer mode register A (TMA).
Output from prescaler W can be used to drive timer A, in which case timer A functions as a time
base for timekeeping.
5.5
Usage Notes
5.5.1
Note on Oscillators
Oscillator characteristics are closely related to board design and should be carefully evaluated by
the user, referring to the examples shown in this section. Oscillator circuit constants will differ
depending on the oscillator element, stray capacitance in its interconnecting circuit, and other
factors. Suitable constants should be determined in consultation with the oscillator element
manufacturer. Design the circuit so that the oscillator element never receives voltages exceeding
its maximum rating.
5.5.2
Notes on Board Design
When using a crystal resonator (ceramic resonator), place the resonator and its load capacitors as
close as possible to the OSC1 and OSC2 pins. Other signal lines should be routed away from the
oscillator circuit to prevent induction from interfering with correct oscillation (see figure 5.10).
80
Avoid
OSC
1
OSC
2
Figure 5.10 Example of Incorrect Board Design
Signal A
Signal B
C
1
C
2
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