NXP Semiconductors MPC5644A Reference Manual

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NXP Semiconductors MPC5644A Reference Manual Manual pdf 107 page image

Operating Modes and ClockingMPC5644A Microcontroller Reference Manual, Rev. 6Freescale Semiconductor 1075.3.2 Block diagramFigure 5-1. System clock diagramFigure 5-2. FMPLL5.3.3 System clock sourcesThe on-chip MHz oscillator, PLL and the top level pin are the possible sources of system clock. The systemclock can be generated using any of the following options:• PLL disabled— MHz crystal oscillator with crystal as the reference— MHz crystal oscillator bypassed• PLL enabled— MHz crystal oscillator (with crystal as the reference) output used as PLL reference frequency— MHz crystal oscillator (bypassed) output used as PLL reference frequency01 10XTAL OSC FMPLLXTALEXTALPLLREFclkcfg[0]SYSDIV/2, /4, /8, /16bypass_sysdivsiu_system_div[1:0]IDF PDODFNDIV LockControl & Status RegistersPHICLKINClock Quality Monitor(CQM)loss ofVCOloss ofReferencesystemclockRCOSCPFD Charge pumpLow Pass Filter VCO/NDIV/IDFCLKIN/ODFFMPLLPHIFMController/6 PHI1