mcf51jf128 Freescale Semiconductor, Inc, mcf51jf128 Datasheet - Page 469

• Manufacturer Part Number: mcf51jf128
• Description: Mcf51jf128 Reference Manual
• Manufacturer: Freescale Semiconductor, Inc

21.5 External Crystal / Resonator Connections
The connections for a crystal/resonator frequency reference are shown in the following
figures. When using low-frequency, low-power mode, the only external component is the
crystal or ceramic resonator itself. In the other oscillator modes, load capacitors (C
and feedback resistor (R
high-gain modes. The following table shows all possible connections.
1. When the frequency of the crystal is 32 kHz and the load capacitors (Cx, Cy) are less than 16 pF, use Connection 4.
2. When the load capacitors (Cx, Cy) are greater than 30 pF, use Connection 3.
3. With the low-power mode, the oscillator has the internal feedback resistor R
Freescale Semiconductor, Inc.
externally with the Connection 3.
EXTAL
Signal
XTAL
Figure 21-2. Crystal/Ceramic Resonator Connections - Connection 1
High-frequency (1~32 MHz), low-power
High-frequency (1~32 MHz), high-gain
Table 21-2. External Caystal/Resonator Connections
External clock/Oscillator input
Oscillator output
Description
Low-frequency (32 kHz), low-power
Low-frequency (32 kHz), high-gain
F
MCF51JF128 Reference Manual, Rev. 2, 03/2011
) are required. In addition, a series resistor (R
Oscillator Mode
Table 21-1. OSC Signal Descriptions
XTAL
Crystal or Resonator
Preliminary
OSC
V
SS
EXTAL
F
. Therefore, the feedback resistor must not be
Connection 1/Connection 3
Connection 2/Connection 4
Connection 2/Connection 4
Chapter 21 Oscillator (OSC)
S
Connection 3
Connection 3
) may be used in
Connections
Connection 1
I/O
O
I
2
2
x
, C
2,3
1
1
/
/
y
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)