MC68HC708AS48 FREESCALE [Freescale Semiconductor, Inc], MC68HC708AS48 Datasheet - Page 108

• Manufacturer Part Number: MC68HC708AS48
• Description: Advance Information
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Clock Generator Module (CGM)
8.4.4 CGM External Connections
Advance Information
108
In its typical configuration, the CGM requires seven external
components. Five of these are for the crystal oscillator and two are for
the PLL.
The crystal oscillator is normally connected in a Pierce oscillator
configuration, as shown in
representation of the internal components and may not represent actual
circuitry. The oscillator configuration uses five components:
The series resistor (R
oscillator guidelines and may not be required for all ranges of operation,
especially with high-frequency crystals. Refer to the crystal
manufacturer’s data for more information.
Figure 8-3
Routing should be done with great care to minimize signal cross talk and
noise. (See
information and more information on the filter capacitor’s value and its
effects on PLL performance.)
•
•
•
•
•
•
•
Crystal, X
Fixed capacitor, C
Tuning capacitor, C
Feedback resistor, R
Series resistor, R
Bypass capacitor, C
Filter capacitor, C
Clock Generator Module (CGM)
also shows the external components for the PLL:
8.10 Acquisition/Lock Time Specifications
1
S
) is included in the diagram to follow strict Pierce
S
F
1
, optional
2
BYP
Figure
, can also be a fixed capacitor
B
8-3.
Figure 8-3
MC68HC708AS48
shows only the logical
for routing
MOTOROLA
—
Rev. 4.0