Software-Programmable Cache Memory with CAM for Low-Power Access
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cache mechanisms in microcontrollers, such as direct mapping and n-associative caches, require significant memory overhead and power consumption, making them unsuitable for dedicated hardware executing known instruction sequences, especially in touch controllers where software expertise can predict instruction usage.
Innovation Solution
A software programmable cache mechanism using a content-addressable memory (CAM) to match instruction addresses, allowing software to indicate which non-volatile memory sections to cache, combined with a volatile cache memory for fast access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If classic cache implementations (direct mapping and n-associative caches) are used, then instruction access speed is improved, but memory overhead and power consumption increase significantly
Solution Approach 1:
The system uses software to automatically manage cache operations by intercepting memory access requests and translating them to cache translations. The software cache manager autonomously handles cache misses, invalidations, and updates without requiring complex hardware cache control logic, thereby reducing hardware resource consumption and power usage while maintaining fast instruction access.
Solution Approach 2:
The patent replaces traditional hardware-based cache management mechanisms with a software-based approach. Instead of using hardware cache controllers and complex address translation logic, the system uses software functions to manage cache translations, reducing the hardware footprint and associated power consumption while achieving similar or better performance.
2Speed
If classic cache implementations are used, then instruction access speed is improved, but device area increases
Solution Approach 1:
The software cache manager performs cache operations through software functions that translate memory addresses to cache locations. This eliminates the need for large hardware cache structures and complex address translation circuits, significantly reducing the area occupied by the cache subsystem while maintaining fast instruction access through the volatile memory cache.
Solution Approach 2:
The patent substitutes hardware cache management circuits with software-based address translation and cache management. This replacement dramatically reduces the hardware area required for cache operations, as software can efficiently manage cache translations without requiring the extensive hardware infrastructure of traditional cache implementations.
3Extent of automation
If hardware cache management is used, then instruction retrieval is automated, but device complexity increases
Solution Approach 1:
The patent replaces complex hardware cache management circuits with software functions. The software cache manager handles address translation, cache miss detection, and invalidation operations through software logic, eliminating the need for complex hardware state machines, priority encoders, and hardware cache controllers, thereby significantly reducing device complexity.
Solution Approach 2:
The system introduces a software intermediary layer (software cache manager) that mediates between memory access requests and the actual memory/cache operations. This software intermediary handles the complexity of cache management centrally, allowing the hardware to remain simple while achieving automated cache management functionality.
Data Source
AI summary
A software programmable cache memory may enable fast execution of frequently used blocks of code. The software programmable cache memory may match incoming instruction addresses with addresses stored in a content-addressable memory (CAM) and may read matching addresses from a volatile cache memory. Instruction addresses which do not match with addresses stored in the CAM may be fetched from a non-volatile memory coupled to the software programmable cache memory.