HD64F7050 RENESAS [Renesas Technology Corp], HD64F7050 Datasheet - Page 76

• Manufacturer Part Number: HD64F7050
• Description: 32-Bit RISC Microcomputer SuperH RISC engine Family/
• Manufacturer: RENESAS [Renesas Technology Corp]

Section 4 Clock Pulse Generator (CPG)
The MD3 and MD2 pins should not be changed while the chip is operating, as normal operation
will not be possible in this case.
4.3
Clock pulses can be supplied from a connected crystal resonator or an external clock.
4.3.1
Circuit Configuration: Figure 4.2 shows the example of connecting a crystal resonator. Use the
damping resistance (Rd) shown in table 4.3. An AT-cut parallel-resonance type crystal resonator
should be used. Load capacitors (CL1, CL2) must be connected as shown in the figure.
The clock pulses generated by the crystal resonator and internal oscillator are sent to the PLL
multiplier circuit, where a multiplied frequency is selected and supplied inside the SH7050 chip
and to external devices.
The crystal manufacturer should be consulted concerning the compatibility between the crystal
and the chip.
Table 4.3
Parameter
Rd ( )
Rev. 5.00 Jan 06, 2006 page 56 of 818
REJ09B0273-0500
Clock Source
Connecting a Crystal Oscillator
Damping Resistance Values (Recommended Values)
Figure 4.2 Connection of the Crystal Oscillator (Example)
EXTAL
4
500
XTAL
R
d
C
L1
8
200
= C
L2
Frequency (MHz)
C
= 18Ð22 pF (recommended value)
C
L2
L1
10
0