TCAM SECDED Error Checking for Low-Latency Entry Validation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Error detection and correction techniques in ternary content addressable memory (TCAM) increase latency and consume chip area or power, making them inefficient for large-scale storage and error handling.
Innovation Solution
Implementing single error correction double error detection (SECDED) error correction codes in TCAMs, which generate and evaluate error correction codes for each entry to detect and correct single and double bit errors, using additional bit values like parity and valid bits, and don't-care states to enhance error detection and correction capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If error detection and correction techniques are implemented in TCAM, then reliability is improved, but latency increases
Solution Approach 1:
The patent pre-calculates and stores error correction codes (ECC) along with the TCAM entries during the write operation. When reading, the pre-stored ECC is immediately available for error detection without requiring additional computation time, thus improving reliability while minimizing latency increase.
Solution Approach 2:
The patent extracts the error detection function into a separate, dedicated circuit that operates in parallel with the main TCAM access path. This allows error checking to be performed without blocking the primary data access flow, reducing the impact on latency while maintaining reliability.
2Reliability
If error detection and correction techniques are implemented in TCAM, then reliability is improved, but chip area increases
Solution Approach 1:
The patent divides the error correction functionality into modular components distributed across the TCAM structure. Each TCAM entry has its associated ECC stored in nearby dedicated storage elements, creating a segmented architecture that provides error correction coverage while distributing the area overhead across the entire chip rather than concentrating it in one location.
Solution Approach 2:
The patent designs the ECC storage elements to serve multiple functions: they store error correction codes for error detection, and can also function as part of the normal TCAM data storage capacity. This multi-functionality reduces the additional chip area required by allowing the same hardware resources to serve dual purposes.
3Reliability
If error detection and correction techniques are implemented in TCAM, then reliability is improved, but power consumption increases
Solution Approach 1:
The patent implements error detection that is activated periodically or selectively based on system conditions rather than continuously. The ECC checking can be enabled during critical operations or when error susceptibility is high, and disabled during normal operations, thus maintaining data integrity when needed while reducing overall power consumption.
Solution Approach 2:
The patent employs self-checking circuitry that automatically detects and corrects errors without requiring external intervention or additional processing power. The ECC mechanism operates autonomously using the pre-stored correction codes, eliminating the need for power-hungry external error checking processors or repeated data verification cycles.
Data Source
AI summary
A ternary content addressable memory (TCAM) may implement complete detection of single and double bit errors for entries. A single error correction double error detection (SECDED) error correction code may be generated and maintained for each entry in the TCAM. The SECDED error correction code may be generated from the parity bit and bits that indicate don't−care conditions in memory cells storing a value for an entry in the TCAM. When an entry of the TCAM is accessed, the value of the entry may be validated with respect to the SECDED error correction code. All single bit errors and double bit errors in the value or data stored for the value, such as a parity bit or value bit, may be detected. All single bit errors and some double bit errors may be corrected.