DMA Controller Clock Management for Power Optimization
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Solution Overview
Problem
The transmission of clock signals along unused DMA channels leads to unnecessary power consumption in electronic devices, particularly in portable devices where battery life is a concern, and sending clock signals at higher frequencies than required further exacerbates this issue.
Innovation Solution
Implementing a method where a DMA controller receives data requests, schedules transfers, sets clock speeds for devices, and disables the DMA channel clock when the scheduler queue is empty, using a clock manager with programmable, frequency division, or phase locked loop circuitry to optimize clock frequencies based on device requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If clock signals are transmitted along DMA channels at high frequencies, then data transfer speed is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic clock frequency adjustment by monitoring the DMA channel utilization status. When a DMA channel is active, the clock manager provides clock signals at the frequency required by the receiving device. When the channel becomes idle, the clock frequency is reduced to a minimal level or stopped entirely. This dynamic adaptation allows the system to maintain high data transfer speeds when needed while minimizing power consumption during idle periods.
Solution Approach 2:
The patent changes the clock frequency parameter based on the operational state of the DMA channel. The clock manager adjusts the clock signal parameters (frequency) according to whether the DMA channel is currently being used for data transfer. This parameter adjustment ensures that high frequencies are only used when necessary for active data transfer, thereby reducing overall power consumption while maintaining transfer speed performance when the channel is in use.
2Reliability
If clock signals are transmitted along unused DMA channels, then device readiness is maintained, but unnecessary power consumption occurs
Solution Approach 1:
The patent implements periodic monitoring of DMA channel utilization status by the clock manager. Instead of continuously transmitting clock signals regardless of need, the system periodically checks whether DMA channels are actively being used. Based on this periodic assessment, the clock manager either maintains or stops clock signal transmission. This periodic action ensures device readiness when channels become active while avoiding continuous unnecessary power consumption during extended idle periods.
Solution Approach 2:
The patent extracts the clock signal transmission function from being a continuous operation and makes it conditional based on actual DMA channel usage. The clock manager selectively removes (stops) clock signal transmission from unused DMA channels while maintaining it only for channels that are actively transferring data. This extraction approach eliminates unnecessary power consumption from idle channels while preserving the ability to quickly resume transmission when channels become active.
Data Source
AI summary
A method and system is disclosed for accessing I/O and memory devices utilizing a DMA controller. Each device may be connected to the DMA controller through an individual channel. Clocking circuitry in the DMA may allow the DMA controller to send signals to each device at a prescribed frequency. Furthermore, the DMA controller is capable of activating and deactivating a channel clock, used in sending signals to the devices, based on the operational status of the individual devices. The DMA controller is also capable of tuning the channel clock dependant on the capabilities of any active devices. In this manner, the amount of bandwidth used during a DMA data transfer can be tailored to the specific requirements of the devices involved with the data transfer.