Datasheet
78K0/Ix2 CHAPTER 28 ELECTRICAL SPECIFICATIONS
R01UH0010EJ0500 Rev.5.00 692
Feb 28, 2012
Caution The pins mounted depend on the product. Refer to Caution 2 at the beginning of this chapter.
28.2 Oscillator Characteristics
28.2.1 X1 Oscillator Characteristics
(T
A = 40 to +105C, 2.7 V VDD 5.5 V, VSS = AVSS = 0 V)
Resonator Recommended Circuit Parameter Conditions MIN. TYP. MAX. Unit
X1 clock
oscillation
frequency (f
X)
Note 1
1.0 10.0 MHz
Ceramic/
crystal
resonator
C1
X2X1
V
SS
C2
Multiplied X1
clock oscillation
frequency
(f
PLL)
Notes 1, 2
40.0 MHz
Notes 1. Indicates only oscillator characteristics. Refer to AC Characteristics for instruction execution time.
2. This can be used only when a 4 MHz resonator is used.
Cautions 1. When using the X1 oscillator, wire as follows in the area enclosed by the broken lines in the above
figures to avoid an adverse effect from wiring capacitance.
• Keep the wiring length as short as possible.
• Do not cross the wiring with the other signal lines.
• Do not route the wiring near a signal line through which a high fluctuating current flows.
• Always make the ground point of the oscillator capacitor the same potential as V
SS.
• Do not ground the capacitor to a ground pattern through which a high current flows.
• Do not fetch signals from the oscillator.
2. Since the CPU is started by the internal high-speed oscillation clock after a reset release, check the
X1 clock oscillation stabilization time using the oscillation stabilization time counter status register
(OSTC) by the user. Determine the oscillation stabilization time of the OSTC register and oscillation
stabilization time select register (OSTS) after sufficiently evaluating the oscillation stabilization time
with the resonator to be used.
Remark For the resonator selection and oscillator constant, customers are requested to either evaluate the oscillation
themselves or apply to the resonator manufacturer for evaluation.