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Architecture
1353
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Serial ATA (SATA) Controller
28.2.11.2 Non CCC Interrupt Configuration
For a standard interrupt handling method where every event that is enabled generates an interrupt, is
handled as follows. For more information, see the AHCI Specification.
After insuring that CCC is disabled, the EN bit in the command completion coalescing control register
(CCC_CTL) is 0, in order for the SATA Core to source interrupts, the interrupt should be enabled at both
the global level (the IE bit in the global HBA control register (GHC) is 1) and at the port level by enabling
the bit fields for the desired interrupt. An enable bit at a Port level that control interrupts dispatch to the
processor interrupt handling resource. So long as the CPU interrupt handler is configured properly, the
CPU receives the interrupt when the enabled event occurs.
28.2.12 EDMA Event Support
The SATA controller makes use of its own built-in DMA and has no need nor utilizes the processor EDMA.
28.2.13 Power Management
The SATA controller can be placed in reduced power modes to conserve power during periods of no use.
The main power management of the peripheral is controlled by the processor power and sleep controller
(PSC). The PSC acts as a master controller for power management of all of the peripherals on the
processor. For detailed information on power management procedures using the PSC, see the
Power and
Sleep Controller (PSC)
chapter.
During times of the SATA peripheral use, the SATASS supports the industry standard power-down modes
(both Partial and Slumber low-power modes) as provided within the SATA specification. These modes
allow for power savings through powering down part of the SERDES PHY and the ability to gate off the
clocks to the link layer. The Port Power Control Module is used to enter and exit these modes that may
have the normal functional clocks gated off.
NOTE:
When SATA communication is in the idle state, that is, when no disk activity takes place, the
communication remains active with both the host and the device sending a logical sync
primitive and scrambled data at the speed negotiated continuously. For power sensitive
applications, the power consumed during the disk inactivity stage might be undesirable and it
might be a desired task to place the communication interface into an electrical idle (Partial or
Slumber) state until data transfer activity is needed in order to conserve power.
28.3 Use Cases
The following sections include some sample program snippets that can be used as a guide for software
development. The example demonstrates one of the ways of creating the necessary structures; properly
aligned system memory resources, initialization, as well as performing basic DMA Read/Write transfer
using Couple of Command Slots.
contains examples in relations to System Memory resource allocations, Structures, and
Subroutines used by the Initialization and Read/Write Transfer functions. The remaining sections include
examples of basic Initialization, DMA Write transfer, and DMA Read transfer examples.