Power, Reset, and Clock Management
•
Device Type coding
•
IOs isolation control
8.1.5.1.5 Clocks Interface
This interface gathers all clock inputs and outputs managed by PRCM modules.
8.1.5.1.6 Resets Interface
This interface gathers all resets inputs and outputs managed by PRCM module.
8.1.5.1.7 Modules Power Management Control Interface
Modules or subsystems in the device are split over 2 categories:
•
Initiator: an initiator is a module able to generate traffic on the device interconnects (typically:
processors, MMU, EDMA).
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Target: a target is a module that cannot generate traffic on the device interconnects, but that can
generate interrupts or DMA request to the system (typically: peripherals). PRCM handles a power
management handshake protocol with each module or sub-system. This protocol allows performing
proper clock and power transition taking into account each module activity or state.
8.1.5.1.8 Initiator Modules Interface
PRCM module handle all initiator modules power management interfaces: MStandby signal MWait signal
8.1.5.1.9 Targets Modules Interface
PRCM module handle all target modules power management interfaces: SIdleReq signal SIdleAck signal
FCLKEN signal
Note: USB Support for SWakeUp
8.1.6 Clock Generation and Management
PRCM provides a centralized control for the generation, distribution and gating of most clocks in the
device. PRCM gathers external clocks and internally generated clocks for distribution to the other modules
in the device. PRCM manages the system clock generation
8.1.6.1
Terminology
The PRCM produces 2 types of clock:
Interface clocks: these clocks primarily provide clocking for the system interconnect modules and the
portions of device's functional modules which interface to the system interconnect modules. In most
cases, the interface clock supplies the functional module's system interconnect interface and registers. For
some modules, interface clock is also used as functional clock. In this document, interface clocks are
represented by blue lines.
Functional clock: this clock supplies the functional part of a module or a sub-system. In some cases, a
module or a subsystem may require several functional clocks: 1 or several main functional clock(s), 1 or
several optional clock(s). A module needs its main clock(s) to be operational. Optional clocks are used for
specific features and can be shutdown without stopping the module
8.1.6.2
Clock Structure
To generate high-frequency clocks, the device supports multiple on-chip DPLLs controlled directly by the
PRCM module. They are of two types of PLLs, referred to ADPLLS and ADPLLLJ throughout this
document.
The ADPLLS module is used for the Core, Display, ARM Subsystem and DDR PLLs
The ADPLLLJ module is used for the peripheral functional clocks
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SPRUH73H – October 2011 – Revised April 2013
Power, Reset, and Clock Management (PRCM)
Copyright © 2011–2013, Texas Instruments Incorporated