NXP Semiconductors freescale K51 Series Reference Manual

Section Number Title Page24.4.3 MCG Internal Reference Clocks..................................................................................................................54524.4.4 External Reference Clock............................................................................................................................54624.4.5 MCG Fixed Frequency Clock .....................................................................................................................54624.4.6 MCG PLL Clock .........................................................................................................................................54724.4.7 MCG Auto TRIM (ATM)............................................................................................................................54724.5 Initialization / Application Information........................................................................................................................54824.5.1 MCG Module Initialization Sequence.........................................................................................................54824.5.2 Using a 32.768 kHz Reference....................................................................................................................55024.5.3 MCG Mode Switching.................................................................................................................................551Chapter 25Oscillator (OSC)25.1 Introduction...................................................................................................................................................................56125.2 Features and Modes......................................................................................................................................................56125.3 Block Diagram..............................................................................................................................................................56225.4 OSC Signal Descriptions..............................................................................................................................................56225.5 External Crystal / Resonator Connections....................................................................................................................56325.6 External Clock Connections.........................................................................................................................................56425.7 Memory Map/Register Definitions...............................................................................................................................56525.7.1 OSC Memory Map/Register Definition.......................................................................................................56525.8 Functional Description..................................................................................................................................................56625.8.1 OSC Module States......................................................................................................................................56625.8.2 OSC Module Modes.....................................................................................................................................56825.8.3 Counter.........................................................................................................................................................57025.8.4 Reference Clock Pin Requirements.............................................................................................................57025.9 Reset..............................................................................................................................................................................57025.10 Low Power Modes Operation.......................................................................................................................................57125.11 Interrupts.......................................................................................................................................................................571K51 Sub-Family Reference Manual, Rev. 6, Nov 2011Freescale Semiconductor, Inc. 21