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iv Intel® PXA255 Processor Developer’s Manual
Contents
3.3.1 32.768 kHz Oscillator............................................................................................3-4
3.3.2 3.6864 MHz Oscillator ..........................................................................................3-4
3.3.3 Core Phase Locked Loop.....................................................................................3-4
3.3.4 95.85 MHz Peripheral Phase Locked Loop..........................................................3-5
3.3.5 147.46 MHz Peripheral Phase Locked Loop ........................................................3-5
3.3.6 Clock Gating.........................................................................................................3-6
3.4 Resets and Power Modes..................................................................................................3-6
3.4.1 Hardware Reset....................................................................................................3-6
3.4.2 Watchdog Reset ...................................................................................................3-7
3.4.3 GPIO Reset ..........................................................................................................3-8
3.4.4 Run Mode .............................................................................................................3-9
3.4.5 Turbo Mode ..........................................................................................................3-9
3.4.6 Idle Mode............................................................................................................3-10
3.4.7 Frequency Change Sequence............................................................................3-11
3.4.8 33-MHz Idle Mode ..............................................................................................3-13
3.4.9 Sleep Mode.........................................................................................................3-15
3.4.10 Power Mode Summary.......................................................................................3-20
3.5 Power Manager Registers...............................................................................................3-22
3.5.1 Power Manager Control Register (PMCR) .........................................................3-23
3.5.2 Power Manager General Configuration Register (PCFR)...................................3-24
3.5.3 Power Manager Wake-Up Enable Register (PWER)..........................................3-25
3.5.4 Power Manager Rising-Edge Detect Enable Register (PRER) ..........................3-26
3.5.5 Power Manager Falling-Edge Detect Enable Register (PFER) ..........................3-27
3.5.6 Power Manager GPIO Edge Detect Status Register (PEDR).............................3-28
3.5.7 Power Manager Sleep Status Register (PSSR) .................................................3-29
3.5.8 Power Manager Scratch Pad Register (PSPR)..................................................3-30
3.5.9 Power Manager Fast Sleep Walk-up Configuration Register (PMFW)...............3-31
3.5.10 Power Manager GPIO Sleep State Registers (PGSR0, PGSR1, PGSR2).........3-31
3.5.11 Reset Controller Status Register (RCSR)...........................................................3-33
3.6 Clocks Manager Registers...............................................................................................3-34
3.6.1 Core Clock Configuration Register (CCCR) .......................................................3-34
3.6.2 Clock Enable Register (CKEN)...........................................................................3-36
3.6.3 Oscillator Configuration Register (OSCC) ..........................................................3-38
3.7 Coprocessor 14: Clock and Power Management............................................................3-38
3.7.1 Core Clock Configuration Register (CCLKCFG).................................................3-39
3.7.2 Power Mode Register (PWRMODE)...................................................................3-40
3.8 External Hardware Considerations..................................................................................3-40
3.8.1 Power-On-Reset Considerations........................................................................3-40
3.8.2 Power Supply Connectivity.................................................................................3-40
3.8.3 Driving the Crystal Pins from an External Clock Source.....................................3-41
3.8.4 Noise Coupling Between Driven Crystal Pins and a Crystal Oscillator...............3-41
3.9 Clocks and Power Manager Register Summary..............................................................3-41
3.9.1 Clocks Manager Register Locations...................................................................3-41
3.9.2 Power Manager Register Summary....................................................................3-41
4 System Integration Unit................................................................................................................4-1
4.1 General-Purpose I/O..........................................................................................................4-1
4.1.1 GPIO Operation....................................................................................................4-1
4.1.2 GPIO Alternate Functions.....................................................................................4-2
4.1.3 GPIO Register Definitions.....................................................................................4-6