DMA Controller Data Backup During Power State Changes
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Solution Overview
Problem
Integrated circuits face data loss or corruption when components are powered down, and existing methods require processor intervention for data backup and restore, diverting resources and prolonging power-down and power-up times.
Innovation Solution
A DMA controller manages data transfers, backups, and restores within integrated circuits, allowing components to power down without data loss by overriding regular transfer parameters during power state changes and using a power manager to notify the DMA controller of low-power events, thus reducing processor resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If processor intervention is used to manage data backup and restore during power state changes, then data integrity is maintained, but processor resources are diverted and power-down/power-up times are prolonged
Solution Approach 1:
The DMA controller autonomously manages data backup and restore operations during power state changes without requiring processor intervention. The controller detects power state changes and automatically executes DMA transfers to preserve data integrity, freeing processor resources for other tasks while maintaining reliable data protection.
Solution Approach 2:
The DMA controller acts as an intermediary between the processor and memory, handling data transfer operations during power state transitions. This mediator function allows the processor to focus on higher-level tasks while the DMA controller manages the critical data preservation and restoration processes.
2Reliability
If processor intervention is used to manage data backup and restore during power state changes, then data integrity is maintained, but power-down and power-up times are prolonged
Solution Approach 1:
The DMA controller autonomously executes data backup and restore operations without waiting for processor involvement. By self-managing these critical operations, the system can faster transition between power states while ensuring data integrity is maintained through automated DMA transfers.
Solution Approach 2:
The DMA controller prepares and executes data backup operations in advance of full system power-down, and restores data immediately upon power-up without requiring processor initialization. This preliminary action approach reduces the effective power-down and power-up times while maintaining data safety.
3Reliability
If retention cells are used to store data during low power operation, then data can be preserved, but additional silicon area is required and power is consumed when cells are active
Solution Approach 1:
The DMA controller serves as an intermediary that transfers data to external memory during power state changes, eliminating the need for dedicated retention cells within the integrated circuit. This approach preserves data integrity while avoiding the silicon area and power consumption penalties associated with on-chip retention storage.
Solution Approach 2:
Instead of using physical retention cells to store data during low-power states, the system creates a copy of the data in external memory via DMA transfers. This copying approach maintains data preservation capability while eliminating the need for additional silicon area and reducing power consumption compared to active retention cells.
4Reliability
If external memory is used to save data during power down, then data can be preserved, but additional power is consumed moving the data
Solution Approach 1:
The DMA controller autonomously manages data transfer to external memory during power state changes without requiring continuous processor power or intervention. This self-service capability allows data preservation to occur efficiently with minimal power consumption, as the DMA controller leverages existing power domains and transfer infrastructure.
Data Source
AI summary
An integrated circuit includes a DMA controller for performing conventional DMA transfers and for backing-up and restoring data during low power events. The integrated circuit includes one or more processor components, one or more peripheral components, a power management circuit and the DMA controller. The power management circuit manages power control within the integrated circuit. The DMA controller includes a DMA engine for executing DMA transfers between different ones of the components and memory based on configuration parameters provided to the DMA engine. A detection circuit configured determines if the power management circuit initiates a power state change. The DMA controller also has circuitry for providing a first set of configuration parameters to the DMA engine if no change in power state is detected and overriding the first set of configuration parameters with a second set of configuration parameters if a change in power state is detected.