DMA Controller Trigger Sequence Generator for Power Saving
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Solution Overview
Problem
Conventional DMA controllers require CPU intervention for periodic data movement, leading to inefficient power consumption and resource utilization, especially in applications where the CPU needs to remain awake or where timer resources are limited.
Innovation Solution
A DMA controller with a built-in trigger sequence generator, including a timer modulus buffer, timer, and multiplexer, allows for internal triggering of data movements, enabling the CPU to sleep while managing multiple data transfers with varying intervals without external CPU intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If software trigger from CPU is used to initiate periodic data movement, then data transfer can be controlled, but CPU must remain awake leading to increased power consumption
Solution Approach 1:
The DMA controller's trigger sequence generator autonomously generates trigger signals for periodic data transfers without requiring CPU intervention. The generator uses a timer to automatically initiate transfers at specified intervals, allowing the CPU to enter sleep mode while the DMA controller independently manages the periodic transfer operations.
2Use of energy by moving object
If on-chip timer is used for triggering DMA transfers, then CPU can sleep, but timer resource may be needed for other applications creating resource conflict
Solution Approach 1:
The trigger sequence generator integrates a timer function directly within the DMA controller, combining the timer resource with the DMA functionality. This eliminates the need for separate external or shared timer resources, allowing the DMA controller to autonomously generate trigger signals without conflicting with other timer-based applications on the chip.
Solution Approach 2:
The trigger sequence generator serves multiple functions: it generates trigger signals for periodic DMA transfers, manages transfer intervals, and replaces the need for separate timer resources. This multi-functional component allows the system to achieve periodic transfers without dedicating exclusive timer resources that would be unavailable for other applications.
3Loss of time
If on-chip timer is used with non-uniform transfer intervals, then timing can be controlled, but software intervention is needed to refresh timer modulus requiring CPU attention
Solution Approach 1:
The trigger sequence generator automatically manages timer modulus refresh operations without CPU intervention. When a DMA transfer completes, the generator autonomously reloads the timer with the appropriate modulus value for the next transfer interval, enabling non-uniform periodic transfers while keeping the CPU in sleep mode throughout the entire process.
4Adaptability or versatility
If single timer resource is used for multiple applications, then resource utilization is efficient, but DMA triggering may conflict with other timer needs
Solution Approach 1:
By integrating the timer function within the DMA controller's trigger sequence generator, the system eliminates resource conflicts. The DMA controller has dedicated access to its internal timer resource, ensuring reliable trigger signal generation without competing with other applications that may require external or shared timer resources.
Data Source
AI summary
A DMA controller includes a built-in timing sequence generator that allows the DMA controller to trigger data movement periodically and/or non-equidistantly, without waking a CPU or other peripherals.