HD64F38602R Datasheet, PDF (106/552 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer

Section 4 Clock Pulse Generators
4.5.2 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
resonator circuit to prevent induction from interfering with correct oscillation (see figure 4.11).
Avoid
Signal A Signal B
C₁
OSC1
C₂
OSC2
Figure 4.11 Example of Incorrect Board Design
Note:
When a crystal resonator or ceramic resonator is connected, consult with the crystal
resonator and ceramic resonator manufacturers to determine the circuit constants because
the constants differ according to the resonator, stray capacitance of the mounting circuit,
and so on.
4.5.3 Definition of Oscillation Stabilization Wait Time
Figure 4.12 shows the oscillation waveform (OSC2), system clock (φ), and microcomputer
operating mode when a transition is made from standby mode, watch mode, or subactive mode, to
active (high-speed/medium-speed) mode, with an resonator connected to the system clock
oscillator.
As shown in figure 4.12, when a transition is made to active (high-speed/medium-speed) mode,
from standby mode, watch mode, or subactive mode, in which the system clock oscillator is
halted, the sum of the following two times (oscillation start time and wait time) is required.
(1) Oscillation Start Time
The time from the point at which the system clock oscillator oscillation waveform starts to change
when an interrupt is generated, until the system clock starts to be generated.
Rev. 3.00 May 15, 2007 Page 74 of 516
REJ09B0152-0300