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Cgm external connections, Configuration, as shown in, Figure 8-2 – Freescale Semiconductor MC68HC08KH12 User Manual

Page 97: Tuning capacitor, c, Series resistor, r, Optional) the series resistor (r, Filter capacitor, c

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MC68HC(7)08KH12

Rev. 1.1

Advance Information

Freescale Semiconductor

97

Tuning capacitor, C

2

(can also be a fixed capacitor)

Feedback resistor, R

B

Series resistor, R

S

(optional)

The series resistor (R

S

) is included in the diagram to follow strict Pierce

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 8-2

also shows the external components for the PLL:

Bypass capacitor, C

BYP

Filter capacitor, C

F

Routing should be done with great care to minimize signal cross talk and
noise.

See

Section 17. Preliminary Electrical Specifications

for capacitor

and resistor values.

Figure 8-2. CGM External Connections

SIMOSCEN

CGMXCLK

R

B

X

1

*R

S

can be zero (shorted) when used with higher-frequency crystals. Refer to manufacturer’s data.

OSC1

OSC2

V

SSA

CGMXFC

V

DDA

V

DD

C

BYP

R

S

*

C

1

C

2

C

F