|
UPD784044 Datasheet, PDF (70/90 Pages) NEC – 16-BIT SINGLE-CHIP MICROCONTROLLER | |||
|
◁ |
µPD784044(A), 784046(A)
(3) Electrical specifications of µPD784044(A2), 784046(A2) (2/6)
Oscillation Circuit Characteristics (TA = â40 to +125 ËC, VDD = 4.5 to 5.5 V, VSS = 0 V)
Resonator
Ceramic resonator or
crystal resonator
Recommended Circuit
VSS
X1
X2
Item
Oscillation frequency (fXX)
MIN.
8
MAX.
20
Unit
MHz
C1
C2
External clock
X1 input frequency (fX)
8
20
MHz
X1
X2
X1 input rise, fall time
OpenNote
0
5
ns
HCMOS inverter
X1 input high-, low-level
20
105
ns
width
Note When the EXTC bit of the oscillation stabilization time specification register (OSTS) = 0. Input the reverse
phase clock of the pin X1 to the pin X2 when the EXTC bit = 1.
Caution When using a system clock oscillation circuit, wire the portion enclosed by the dotted line in
the diagram above as follows to prevent adverse influence from wiring capacitance:
⢠Keep the wiring length as short as possible.
⢠Do not cross the wiring with any other signal lines. Do not route the wiring in the vicinity
of a line through which a high alternating current flows.
⢠Always keep the ground potential for the capacitor in the oscillation circuit at the same
potential as VSS. Do not ground the capacitor to a ground pattern through which a high current
flows.
⢠Do not extract any signal from the oscillation circuit.
70
|
▷ |