mcf5282 Freescale Semiconductor, Inc, mcf5282 Datasheet - Page 182

• Manufacturer Part Number: mcf5282
• Manufacturer: Freescale Semiconductor, Inc

Clock Module
The RFD is not in the feedback loop of the PLL, so changing the RFD divisor does not affect PLL
operation.
Figure 9-5
Actual component values depend on crystal specifications.
The following subsections describe each major block of the PLL. Refer to
functional sub-blocks interact.
9.7.4.1
The PFD is a dual-latch phase-frequency detector. It compares both the phase and frequency of the
reference and feedback clocks. The reference clock comes from either the crystal oscillator or an external
clock source.
9-12
shows the external support circuitry for the crystal oscillator with example component values.
Phase and Frequency Detector (PFD)
V
MCF5282 and MCF5216 ColdFire Microcontroller User’s Manual, Rev. 3
SS
C1
ON-CHIP
EXTAL
Figure 9-5. Crystal Oscillator Example
RF
XTAL
RS
V
C2
SSSYN
8-MHz CRYSTAL CONFIGURATIO
C1 = C2 = 16 pF
RF = 1 MΩ
RS = 470 Ω
Figure
Freescale Semiconductor
to see how these