mcf51ac256a Freescale Semiconductor, Inc, mcf51ac256a Datasheet - Page 370

• Manufacturer Part Number: mcf51ac256a
• Description: Mcf51ac Flexis
• Manufacturer: Freescale Semiconductor, Inc

Multipurpose Clock Generator (S08MCGV3)
16.1.1
Key features of the MCG module are:
16-2
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Frequency-locked loop (FLL)
— Internal or external reference clock can be used to control the FLL
Phase-locked loop (PLL)
— Voltage-controlled oscillator (VCO)
— Modulo VCO frequency divider
— Phase/Frequency detector
— Integrated loop filter
— Lock detector with interrupt capability
Internal reference clock
— Nine trim bits for accuracy
— Can be selected as the clock source for the MCU
External reference clock
— Control for a separate crystal oscillator
— Clock monitor with reset capability
— Can be selected as the clock source for the MCU
Reference divider is provided
Clock source selected can be divided down by 1, 2, 4, or 8
BDC clock (MCGLCLK) is provided as a constant divide-by-2 of the DCO output whether in an
FLL or PLL mode.Three selectable digitally controlled oscillators (DCOs) optimized for different
frequency ranges.
Option to maximize DCO output frequency for a 32,768 Hz external reference clock source.
The PLL can be used to drive MCGPLLSCLK even when MCGOUT is driven from one of the
reference clocks (PBE mode).
Features
MCF51AC256 ColdFire Integrated Microcontroller Reference Manual, Rev. 5
Freescale Semiconductor