Datasheet

Section 5 Clock Pulse Generator
Rev. 3.00 Sep. 10, 2007 Page 88 of 528
REJ09B0216-0300
5.5 External Oscillators
There are two methods to supply external clock pulses into this LSI: connecting a crystal or
ceramic resonator, and an external clock. Oscillation pins OSC1 and OSC2 are common with
general ports PC0 and PC1, respectively. To set pins PC0 and PC1 as crystal resonator or external
clock input ports, refer to section 5.2.4, Clock Control/Status Register (CKCSR).
Figure 5.11 shows a block diagram of an external clock oscillator.
OSC2
OSC1
LPM*
1
600 kΩ*
2
Notes: 1. LPM: Power-down mode (standby mode, subactive mode, or subsleep mode)
2. Values here are reference values.
Figure 5.11 Block Diagram of External Clock Oscillator
5.5.1 Connecting Crystal Resonator
Figure 5.12 shows an example of connecting a crystal resonator. An AT-cut parallel-resonance
crystal resonator should be used. Figure 5.13 shows the equivalent circuit of a crystal resonator. A
resonator having the characteristics given in table 5.1 should be used.
C
1
C
2
PC0/OSC1
PC1/OSC2/CLKOUT
C = C = 10 to 22 pF
1 2
Figure 5.12 Example of Connection to Crystal Resonator