Gray Code Timer Transfer Fault Detection in Semiconductor Circuits
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Solution Overview
Problem
Existing methods for error detection in asynchronous data transfers from a general-purpose timer to CPUs in semiconductor devices for vehicles are ineffective, leading to potential capture of invalid data due to increased Hamming distance when error detection codes are added to gray code timer count values, making it difficult to detect faults in the transfer path.
Innovation Solution
A semiconductor device with a timer unit that converts binary count values to gray code and a processing unit that synchronizes and compares duplicated gray code data to detect faults, ensuring the difference between count values is within a predetermined threshold to accurately determine path faults, thereby improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an error detection code is added to the timer count value converted into gray code for asynchronous transfer, then error detection capability is improved, but the Hamming distance between adjacent codes increases causing the CPU to capture invalid data
Solution Approach 1:
The patent divides the error detection function into two separate paths: one path transfers the timer count value in gray code to the CPU for normal operation, while another path transfers the same value through a different route to a fault detection unit. This segmentation allows error detection without adding codes to the original data stream, thus maintaining the Hamming distance properties of gray code.
Solution Approach 2:
The patent introduces an intermediary fault detection unit that receives timer count values through a separate path from the main processing path. This intermediary unit compares the received value with the CPU's captured value to detect faults, acting as a mediator that enables error detection without modifying the original gray code transmission.
2Reliability
If fault detection mechanisms are implemented for asynchronous transfer paths, then system reliability is improved, but device complexity increases
Solution Approach 1:
The patent creates a copy of the timer count value transmission path, where the original path sends gray code to the CPU and the copied path sends the same value to the fault detection unit. This copying approach enables fault detection by comparing the original and copied values, adding minimal complexity while maintaining reliability.
Solution Approach 2:
The fault detection unit provides feedback by comparing the timer count value received through the separate path with the value captured by the CPU. When discrepancies are detected, the system can respond appropriately, creating a feedback mechanism that enhances reliability without significantly increasing complexity.
Data Source
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AI summary
A semiconductor device has a timer unit (10) and a processing unit (100). The timer unit (10) includes a binary counter (11), a first converter (12) that converts a first count value output from the binary counter (11) to a gray code to output as first gray code data (CNTVALUEG). The processing unit (100) includes a first synchronizer (101) that captures the first gray code data (CNTVALUEG) transferred from the timer unit (10) in synchronization with the system clock signal and outputs the captured first gray code data (CNTVALUEG) as second gray code data (CNTVALUEGS_m), and a fault detection unit (104) that generates a data for fault detection (CNTVALUEGS_c) based on the first gray code data (CNTVALUEG) transferred from the timer unit (10) and compares a second count value (CNTVALUEB_m) based on the second gray code data (CNTVALUEGS_m) with a third counter value (CNTVALUEB_c) based on the data for fault detection (CNTVALUEGS_c).