SH7760 Datasheet, PDF (529/1345 Pages) Renesas Technology Corp – SuperHTM RISC engine

12.5.9 Controlling CKIO Output Clock
The CKIO pin can be switched between clock output and the high-impedance state by means of
the CKOEN bit in FRQCR. When the CKIO pin goes to the high-impedance state, it is pulled up.
12.6 Usage Notes
(1) Using a crystal resonator
Place the crystal resonator and capacitors CL1 and CL2 close to the EXTAL and XTAL pins.
To prevent induction from interfering with correct oscillation, ensure that no other signal lines
cross the signal lines for these pins.
CL1
CL2
Avoid crossing signal lines
R
EXTAL XTAL
Recommended values
CL1 = CL2 = 0–33 pF
R=0Ω
This LSI
Note: The values for CL1, CL2, and the damping resistance should be determined after
consultation with the crystal resonator manufacturer.
Figure 12.2 Points for Attention when Using Crystal Resonator
(2) Inputting external clock from EXTAL pin
Make no connection to the XTAL pin.
(3) Using a PLL oscillation circuit
Separate VDD-CPG and VSS-CPG from the other VDD and VSS lines at the board power
supply source, and insert resistors RCB and RB and bypass capacitors CPB and CB, close to
the pins.
Rev. 1.0, 02/03, page 479 of 1294