Texas Instruments TMS320DM643x Clock Management, Module Clock ON/OFF, PLL Bypass and Power Down

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Clock Management

7.3Clock Management

7.3.1 Module Clock ON/OFF

The module clock on/off feature allows software to disable clocks to module individually, in order to reduce the module's active power consumption to 0. The DM643x DMP is designed in full static CMOS; thus, when a module clock stops, the module's state is preserved. When the clock is restarted, the module resumes operating from the stopping point.

Note: Stopping clocks to a module only affects active power consumption, it does not affect leakage power consumption.

If a module's clock(s) is stopped while being accessed, the access may not occur, and could potentially lock-up the device. User must ensure that all of the transactions to the module are finished prior to stopping the clocks. The power and sleep controller (PSC) controls module clock gating. The PSC provides some protection against system hang by monitoring the internal bus activity—it only gates internal clock to the module after checking that there is no access to the module from the internal bus.

The procedure to turn module clocks on/off using the PSC is described in Chapter 6. Furthermore, special consideration must be given to DSP clock on/off. The procedure to turn the DSP clock on/off is further described in Section 7.4.2.

Some peripherals provide additional power saving features by clock gating components within its module boundary. See peripheral-specific user's guide for more details on these additional power saving features.

7.3.2 Module Clock Frequency Scaling

Module clock frequency is scalable by programming the PLL's multiply and divide parameters. Reducing the clock frequency reduces the active switching power consumption linearly with frequency. It has no impact on leakage power consumption.

Chapter 4 and Chapter 5 describe the how to program the PLL frequency and the frequency constraints.

7.3.3 PLL Bypass and Power Down

You can bypass the PLLs in the DM643x DMP. Bypassing the PLLs sends the PLL reference clock (MXI/CLKIN) instead of the PLL output (PLLOUT) to the SYSCLK dividers (PLLDIVn) of the PLLC. The PLL reference clock is typically at 27 MHZ; therefore, you can use this mode to reduce the core and module clock frequencies to very low maintenance levels without using the PLL during periods of very low system activity. Furthermore, you can power-down the PLL when bypassing it to save additional active power.

Chapter 4 and Chapter 5 describe PLL bypass and PLL power down.

SPRU978E–March 2008

Power Management

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Contents Reference Guide Submit Documentation Feedback Contents PLL Controller Command Register Pllcmd Boot Modes ResetList of Figures List of Tables Submit Documentation Feedback Related Documentation From Texas Instruments Read This FirstAbout This Manual Notational ConventionsTMS320C6000, C6000 are trademarks of Texas Instruments Introduction Introduction Block DiagramPeripherals Components of the DSP Subsystem DSP Subsystem in TMS320DM643x DMPSubmit Documentation Feedback TMS320C64x+ Megamodule TMS320C64x+ CPU TMS320C64x+ Megamodule Block Diagram 1 L1P Controller Memory ControllersL1D L1P3 L2 Controller 2 L1D ControllerInternal DMA Idma External Memory Controller EMCInternal Peripherals Power-Down Controller PDCInterrupt Controller Intc Bandwidth Manager Submit Documentation Feedback Memory Map Memory Interfaces Overview System MemoryInternal Peripherals Memory MapDSP Internal Memory L1P, L1D, L2 External MemoryAsynchronous Emif Interface Memory Interfaces Overview1 DDR2 External Memory Interface External Memory InterfaceSubmit Documentation Feedback Overview Clock Domains Device ClockingSystem Clock Modes and Fixed Ratios for Core Clock Domains OverviewClock Domains Core DomainsHecc Overall Clocking DiagramDivider Core Frequency FlexibilityExample PLL1 Frequencies and Dividers 27 MHZ Clock Input Core VoltageExample PLL2 Frequencies Core Voltage = 3 DDR2/EMIF ClockPeripheral I/O Domain Clock 4 I/O DomainsVideo Processing Back End Possible Clocking Modes VPSSCLKCTL.MUXSEL Bit Clocking Mode DescriptionPLL Controller PLL1 Control PLL ModulePLLC1 Output Clock Used by Device Clock GenerationSteps for Changing PLL1/Core Domain Frequency System PLLC1 Output ClocksInitialization to PLL Mode from PLL Power Down Changing PLL Multiplier Example 5-1. Calculating Number of Clock Cycles N Changing Sysclk DividersOutput Clock Used by PLL2 ControlDDR PLLC2 Output Clocks PlloutSteps for Changing PLL2 Frequency 2.1 DDR2 Considerations When Modifying PLL2 FrequencyInitialization to PLL Mode from PLL Power Down Changing PLL Multiplier Example 5-2. Calculating Number of Clock Cycles N PLL Controller Registers PLL and Reset Controller ListPLL and Reset Controller Registers PLL and Reset Controller Base Address End Address SizePeripheral ID Register PID Field Descriptions Reset Type Status Register RstypeReset Type Status Register Rstype Field Descriptions Peripheral ID Register PIDPLL Control Register Pllctl Field Descriptions PLL Control Register PllctlD1EN PLL Multiplier Control Register PllmPLL Controller Divider 1 Register PLLDIV1 PLL Multiplier Control Register Pllm Field DescriptionsD3EN PLL Controller Divider 2 Register PLLDIV2PLL Controller Divider 3 Register PLLDIV3 D2ENOD1EN Oscillator Divider 1 Register OSCDIV113. Bypass Divider Register Bpdiv Field Descriptions Bypass Divider Register BpdivBpden Stable PLL Controller Command Register PllcmdPLL Controller Status Register Pllstat GosetALN2 PLL Controller Clock Align Control Register AlnctlALN2 ALN1 ALN3SYS3 SYS2 SYS1 Plldiv Ratio Change Status Register DchangeSYS3 Obsen Clock Enable Control Register Cken18. Clock Enable Control Register Cken Field Descriptions Obsen AuxenObson Auxon Clock Status Register Ckstat19. Clock Status Register Ckstat Field Descriptions BponSYS3ON Sysclk Status Register Systat20. Sysclk Status Register Systat Field Descriptions SYS3ON SYS2ON SYS1ONPower and Sleep Controller Power and Sleep Controller PSC Integration DM643x DMP Default Module Configuration Power Domain and Module TopologyNumber Module Name Default Module State MDSTAT.STATE Module States Power Domain and Module StatesPower Domain States Module StatesModule State Transitions Local ResetPower Domain State Transitions Executing State TransitionsInterrupt Events IcePick Emulation CommandsIcePick Emulation Support in the PSC PSC InterruptsInterrupt Registers Local Reset Emulation EventsModule State Emulation Events Offset Register Description Power and Sleep Controller PSC RegistersInterrupt Handling PSC RegistersInterrupt Evaluation Register Inteval Peripheral Revision and Class Information Register PIDInterrupt Evaluation Register Inteval Field Descriptions Module Error Clear Register 1 MERRCR1 Field Descriptions Module Error Pending Register 1 MERRPR1Module Error Clear Register 1 MERRCR1 Module Error Pending Register 1 MERRPR1 Field DescriptionsPower Domain Transition Status Register Ptstat Power Domain Transition Command Register PtcmdGOSTAT0 Pordone Power Domain Status 0 Register PDSTAT0Pordone POR StateNext Power Domain Control 0 Register PDCTL014. Module Status n Register MDSTATn Field Descriptions Module Status n Register MDSTATnEmuihbie Module Control n Register MDCTLn15. Module Control n Register MDCTLn Field Descriptions Emuihbie Emurstie LrstSubmit Documentation Feedback Power Management PSC and Pllc Overview Power Management Features DescriptionModule Clock Frequency Scaling PLL Bypass and Power DownClock Management Module Clock ON/OFFDSP Module Clock on DSP Sleep Mode ManagementDSP Sleep Modes DSP Module Clock ON/OFFVideo DAC Power Down 3.3 V I/O Power DownDSP Module Clock Off Submit Documentation Feedback Interrupt Controller Submit Documentation Feedback System Module Pin Multiplexing Control Device ConfigurationDevice Boot Configuration Status Device IdentificationHPI Control Timer ControlVpss Clock and DAC Control 3 DDR2 VTP ControlDSP CFG Bandwidth ManagementBus Master DMA Priority Control TMS320DM643x DMP Master IDsDSP DMA DSP CFG Emac Edma Transfer Controller ConfigurationBoot Control TMS320DM643x DMP Default Master PrioritiesSubmit Documentation Feedback 10.3 Reset10.1 10.2Type Initiator Effect Reset PinsDevice Configurations at Reset Reset TypesSoftware Reset Disable SwRstDisable DSP ResetDSP Local Reset DSP Module ResetSynchronous Reset SyncReset Boot Modes Submit Documentation Feedback Table A-1. Document Revision History Revision HistoryAdditions/Modifications/Deletions DSP Products ApplicationsRfid
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