SH7058 Datasheet, PDF (118/1130 Pages) Renesas Technology Corp – Renesas SuperHTM RISC engine

When writing to SYSCR2
15
Address: H'FFFFF70A
H'3C
87
0
Write data
Figure 5.3 Writing to SYSCR2
5.3 Clock Source
Clock pulses can be supplied from a connected crystal oscillator or an external clock.
5.3.1 Connecting a Crystal Oscillator
Circuit Configuration: Figure 5.4 shows an example of connecting a crystal oscillator. Use the
damping resistance (Rd) shown in table 5.4. An AT-cut parallel-resonance type crystal oscillator
should be used. Load capacitors (CL1, CL2) must be connected as shown in the figure.
The clock pulses generated by the crystal oscillator and internal oscillator are sent to the PLL
multiplier circuit, where a multiplied frequency is selected and supplied inside the SH7058 chip
and to external devices.
The crystal oscillator manufacturer should be consulted concerning the compatibility between the
crystal oscillator and the chip.
CL2
EXTAL
CL1
XTAL
Rd
CL1 = CL2 = 18 to 22 pF
Figure 5.4 Connection of Crystal Oscillator (Example)
Table 5.4 Damping Resistance Values (Recommended Values)
Parameter
5
Rd (Ω)
500
Frequency (MHz)
10
0
Rev. 3.0, 09/04, page 77 of 1086