SH7101 Datasheet, PDF (81/486 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer

4. Clock Pulse Generator
Section 4 Clock Pulse Generator
This LSI has an on-chip clock pulse generator (CPG) that generates the system clock (φ), internal
clock (φ/2 to φ/8192, Pφ/2 to Pφ/1024), and peripheral clock (Pφ). The CPG consists of an
oscillator, PLL circuit, and prescaler. A block diagram of the clock pulse generator is shown in
figure 4.1. The frequency from the oscillator can be modified by the PLL circuit.
PLLCAP
EXTAL
XTAL
Oscillator
PLL circuit
Clock divider
(× 1/2)
MD2
Clock mode
MD3
control circuitry
Prescaler
Prescaler
φ
φ/2 to
φ/8192
Pφ/2 to
Pφ
Pφ/1024
Within the LSI
Figure 4.1 Block Diagram of Clock Pulse Generator
4.1 Oscillator
Clock pulses can be supplied from a connected crystal resonator or an external clock.
4.1.1 Connecting Crystal Resonator
Circuit Configuration: A crystal resonator can be connected as shown in figure 4.2. Use the
damping resistance (Rd) listed in table 4.1. Use an AT-cut parallel-resonance type crystal
resonator that has a resonance frequency of 4 to 10 MHz. It is recommended to consult crystal
dealer concerning the compatibility of the crystal resonator and the LSI.
CPG0100A_010020030200
Rev.2.00 Sep. 27, 2007 Page 47 of 448
REJ09B0394-0200