Information
Section Number Title Page
24.4.5 MCG Fixed frequency clock .......................................................................................................................452
24.4.6 MCG PLL clock ..........................................................................................................................................453
24.4.7 MCG Auto TRIM (ATM)............................................................................................................................453
24.5 Initialization / Application information........................................................................................................................454
24.5.1 MCG module initialization sequence...........................................................................................................454
24.5.2 Using a 32.768 kHz reference......................................................................................................................456
24.5.3 MCG mode switching..................................................................................................................................457
Chapter 25
Oscillator (OSC)
25.1 Introduction...................................................................................................................................................................467
25.2 Features and Modes......................................................................................................................................................467
25.3 Block Diagram..............................................................................................................................................................468
25.4 OSC Signal Descriptions..............................................................................................................................................468
25.5 External Crystal / Resonator Connections....................................................................................................................469
25.6 External Clock Connections.........................................................................................................................................470
25.7 Memory Map/Register Definitions...............................................................................................................................471
25.7.1 OSC Memory Map/Register Definition.......................................................................................................471
25.8 Functional Description..................................................................................................................................................472
25.8.1 OSC Module States......................................................................................................................................473
25.8.2 OSC Module Modes.....................................................................................................................................474
25.8.3 Counter.........................................................................................................................................................476
25.8.4 Reference Clock Pin Requirements.............................................................................................................476
25.9 Reset..............................................................................................................................................................................476
25.10 Low Power Modes Operation.......................................................................................................................................477
25.11 Interrupts.......................................................................................................................................................................477
Chapter 26
RTC Oscillator
26.1 Introduction...................................................................................................................................................................479
26.1.1 Features and Modes.....................................................................................................................................479
K20 Sub-Family Reference Manual, Rev. 2, Feb 2012
Freescale Semiconductor, Inc. 19