Datasheet

Section 5 Clock Pulse Generator
Rev. 2.00 Jul. 04, 2007 Page 88 of 692
REJ09B0309-0200
Bit Bit Name
Initial
Value
R/W Description
1 OSCF —* R OSC Flag
This bit indicates which oscillator is acting as the
system clock pulse generator.
0: The system clock oscillator is the generator
(operation of the on-chip oscillator for system clock
stopped)
1: The on-chip oscillator for the system clock is the
generator (system clock oscillator stopped)
0 — 0 R/W Reserved
The write value should always be 0.
Note: * The initial value depends on the IRQAEC pin state. For details, see table 5.1.
5.2 System Clock Generator
Clock pulses can be supplied to the system clock divider either by connecting a crystal or ceramic
resonator, or by providing an external clock input.
The system clock oscillator or the on-chip oscillator for the system clock is selectable, as shown in
figure 5.1. For details on how to select the oscillator, see section 5.2.4, Selecting On-Chip
Oscillator for System Clock.
5.2.1 Connecting Crystal Resonator
Figure 5.2 shows a typical method of connecting a crystal resonator. An AT-cut parallel-resonance
crystal resonator should be used.
For precautionary notes on connection of the crystal resonator, see section 5.5.2, Notes on Board
Design.
C
1
C
2
OSC1
OSC2
Frequency Manufacturer
4.19 MHz NIHON DEMPA
KOGYO.,LTD.
Product Type
NR-18
C
1
, C
2
Recommended Value
12 pF ±20%
Figure 5.2 Typical Connection to Crystal Resonator